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2010 Murray Electrical issue

#1

B

BGS Mex

I have a 2010 Murray MODEL: 42L18G60X8A SERIES: 080310001196 that electrically is driving me crazy.
Issue: Although the starter solenoid tests that it is operational, it does not function with the key switch (new). The white wire has voltage when the key is turned to “start”, and the black has continuity to ground. When powered directly with 12 v. at the solenoid (the terminal for the white wire), the starter operates as it should.

There are no obvious damages to the wiring harnesses and the (new) fuel solenoid operates. I have tested everything (Meter) that I can think of, however there is no change. I have been unable to locate a wiring diagram for this model.
Does anyone have one?


#2

Its Me

Its Me

all your safety switches tested to show current going through them, Joe


#3

B

BGS Mex

Yes: and the 4 terminal seat switch has continuity (when connected and pressed down) has continuity between the Green and Grey conductors. All the others seem to test Ok. The thing that baffles me is that when the (new) ignition swich is turned to "Start" (white) there is 12 v yet it doesn't activate the starter. When I put 12v directly to that (white) terminal the engine turnd over as it should. I have been unable to locate a wiring schematic for this model!
OEM: Murray TYPE: Lawn Tractor

MODEL: 42L18G60X8A

SERIES: 080310001196


#4

ILENGINE

ILENGINE

BGS Mex said:
Yes: and the 4 terminal seat switch has continuity (when connected and pressed down) has continuity between the Green and Grey conductors. All the others seem to test Ok. The thing that baffles me is that when the (new) ignition swich is turned to "Start" (white) there is 12 v yet it doesn't activate the starter. When I put 12v directly to that (white) terminal the engine turnd over as it should. I have been unable to locate a wiring schematic for this model!
OEM: Murray TYPE: Lawn Tractor

MODEL: 42L18G60X8A

SERIES: 080310001196
Click to expand...
May want to try a test light on that white wire to see if it will light a light. Just because a meter shows 12 volts doesn't mean it will carry enough current to engage the solenoid.


#5

Scrubcadet10

Scrubcadet10

electrical schematic

42L18G60X8A Schematic.jpg

drive.google.com drive.google.com


#6

A

Auto Doc's

Check this out:

Chickanic mower wiring - Search Videos

www.bing.com www.bing.com


#7

B

BGS Mex

ILENGINE said:
May want to try a test light on that white wire to see if it will light a light. Just because a meter shows 12 volts doesn't mean it will carry enough current to engage the solenoid.
Click to expand...
Thanx so much; I will check it again. Thinking about it; at one point I thought there might not be enough amperage there.


#8

B

BGS Mex

Auto Doc's said:
Check this out:

Chickanic mower wiring - Search Videos

www.bing.com www.bing.com
Click to expand...
I think that I have watched every related video at least twice.


#9

R

RevB

BGS Mex said:
Thanx so much; I will check it again. Thinking about it; at one point I thought there might not be enough amperage there.
Click to expand...
Trace the white back and run a separate new wire to the switch S terminal that supplies the 12v solenoid. If that works you're looking at two relays that must operate to send power on to the solenoid.


#10

O

outdoorpowermike

The red wire at the ign switch plug is the 12 volt feed not the white wire. Put a test light at back side of wire harness and turn key to is if switch is sending voltage out to starter solenoid. If power is coming out of switch test at starter solenoid the same way. If good there make sure ground wire to solenoid is on


#11

B

BGS Mex

outdoorpowermike said:
The red wire at the ign switch plug is the 12 volt feed not the white wire. Put a test light at back side of wire harness and turn key to is if switch is sending voltage out to starter solenoid. If power is coming out of switch test at starter solenoid the same way. If good there make sure ground wire to solenoid is on
Click to expand...
Hi: This is a new switch. I have even tested (OK) the start solenoid, and tried another from an operational (Husqvarna) tractor. Yes; the red (letter B) on the switch is 12V feeding the switch. The White (S) is to the Start solenoid (Power) terminal. Both "main" grounds are fine. When I run 12 V direct from the battery to this white (solenoid) terminal the solenoid activates and powers the starter. When the ign. switch is turned to Start (S) there is 8.46 V there and the white solenoid conductor has 11.46 V (?). The battery reads 12.70 volts. I have an operational Husqvarna in the shop and I tried this Ignition Switch and it too tested 8.5 V at the "S" terminal. Both ignition switches work fine on the Husqvarna and test at 12.68 Volts. Both Solenoids work too!
Thank you: I am at a loss with this thing. I have been unable to find a correct Murray Electrical schematic and the one from the parts manual is pretty useless. I have been a licensed Canadian Mechanic for many decades and am embarrassed by this! I'm "retired" here in Mexico; I mostly do PWC's, outboards (Yamaha) and light construction equipment; there aren't many tractors sold here.

Attachments





#12

A

Auto Doc's

Hi BGS mex,

For true load testing, rig an old round incandescent head lamp and use it for load testing the wires.

Ohm testing can fool you into thinking a wire is good even if it only has 1 strand left, but it cannot carry the needed Amperage. A small test light has almost no load.

Another method is to connect your meter while set to "V" to each end of a wire and see if it read voltage when you activate a circuit. If it reads voltage there is a problem with a connection or the wire

I did not see your battery ground cable in the picture. Check where it is bolted to the chassis to make sure it is clean and tight. I've seen a lot of bad chassis grounds on riders.

Last but not least, check the fuse holder for loose pin fit to the fuse or if they have been heated up a lot.

I always like to say: "The smaller the machine, the bigger the problem can be to find".

Short story:

I had a Husqvarna 20YTH46 rider a while back that had me stumped for 2 days until I found that the ground for the start solenoid had broken at the crimp fitting for the headlamp harness connector. The 2 grounds were crimped together with the harness ground and then doubled back to the start solenoid. I had to open up the harness jacket tubing to finally find the solenoid ground wire loose down inside the tubing.


#13

B

BGS Mex

BGS Mex said:
Hi: This is a new switch. I have even tested (OK) the start solenoid, and tried another from an operational (Husqvarna) tractor. Yes; the red (letter B) on the switch is 12V feeding the switch. The White (S) is to the Start solenoid (Power) terminal. Both "main" grounds are fine. When I run 12 V direct from the battery to this white (solenoid) terminal the solenoid activates and powers the starter. When the ign. switch is turned to Start (S) there is 8.46 V there and the white solenoid conductor has 11.46 V (?). The battery reads 12.70 volts. I have an operational Husqvarna in the shop and I tried this Ignition Switch and it too tested 8.5 V at the "S" terminal. Both ignition switches work fine on the Husqvarna and test at 12.68 Volts. Both Solenoids work too!
Thank you: I am at a loss with this thing. I have been unable to find a correct Murray Electrical schematic and the one from the parts manual is pretty useless. I have been a licensed Canadian Mechanic for many decades and am embarrassed by this! I'm "retired" here in Mexico; I mostly do PWC's, outboards (Yamaha) and light construction equipment; there aren't many tractors sold here.
Click to expand...
Thanx again: I have the Harness Jackets removed. This Voltage thing at the switch (S) has me stumped; especially as both the Murray start switch and Solenoid work fine on the Husqvarna. The solenoid "Ground" (black wire) is alone. I will check where the headlight ground wire terminates. As it isn't attached I didn't think it would affect anything.


#14

B

BGS Mex

Auto Doc's said:
Hi BGS mex,

For true load testing, rig an old round incandescent head lamp and use it for load testing the wires.

Ohm testing can fool you into thinking a wire is good even if it only has 1 strand left, but it cannot carry the needed Amperage. A small test light has almost no load.

Another method is to connect your meter while set to "V" to each end of a wire and see if it read voltage when you activate a circuit. If it reads voltage there is a problem with a connection or the wire

I did not see your battery ground cable in the picture. Check where it is bolted to the chassis to make sure it is clean and tight. I've seen a lot of bad chassis grounds on riders.

Last but not least, check the fuse holder for loose pin fit to the fuse or if they have been heated up a lot.

I always like to say: "The smaller the machine, the bigger the problem can be to find".

Short story:

I had a Husqvarna 20YTH46 rider a while back that had me stumped for 2 days until I found that the ground for the start solenoid had broken at the crimp fitting for the headlamp harness connector. The 2 grounds were crimped together with the harness ground and then doubled back to the start solenoid. I had to open up the harness jacket tubing to finally find the solenoid ground wire loose down inside the tubing.
Click to expand...
Thank you: The battery in the Murray is under the seat with the negative attached to the upright part of the frame there. I have also tried connecting a ground wire directly to the solenoid with no effect. The ground to the ignition switch is fed from the "Cowl Harness" and attached to the frame there. amperage and ground are among the thoughts that I have had. I just can't get a handle on why there is 11.81 volts on the white wire at the solenoid, and 8.50 at the ignition switch "S" terminal with the wire connected to it.. This makes absolutely no sense to me. I have been spoiled with the quality of the Electrical schematics from YAMAHA I guess.


#15

B

BGS Mex

You folks have given me a thought. Given the Murray switch/solenoid combination tests and works fine on the Husqvarna; It must be something in the Murray wiring (positive, and ground) to the switch. I am thinking that I will disconnect the switch from the harness and connect seperate positive (B), ground (M) and solenoid S(white) and see what affect it may have. At the least it might give yet another idea.


#16

A

Auto Doc's

Here is a generic diagram that may help:



#17

B

BGS Mex

Auto Doc's said:
Here is a generic diagram that may help:

Click to expand...
Thanx: I already have it. What do you think of my latest idea?


#18

A

Auto Doc's

Just be careful that you are running 12V power to the correct circuit, same with ground. An inline fuse on your test wires would be wise. As a precaution disconnect the 2-stator wire to avoid any possible accidental damage while testing.

I use a basic Power Probe circuit tester most of the time when doing tests like this, it has built in safety circuit breaker.


#19

A

Auto Doc's

BGS Mex said:
Thanx: I already have it. What do you think of my latest idea?
Click to expand...
Is the diagram scrubcadet10 sent you correct for your machine?


#20

T

Telesis

You mentioned the ground terminal on the switch was "M" and I'm pretty sure that's the kill circuit to the ignition. The "G" terminal is the ground. I would try a jumper between B and S right at the switch. It can be in the off position and it should still pull in the solenoid when you connect the jumper.

As was previously mentioned, put a decent load(I use and old headlight) in parallel with your meter leads when you are measuring those voltages. I'd be curious if you still have the goofy 8.5 at the switch and 11.8 at the solenoid. I'd really like you to try this and post your results!

Finally, and I apologize if you mentioned it(I can't check as this server will time out on me!), I would double check all grounding, i.e. battery to chassis, chassis to engine, solenoid to chassis, etc. I'd disassemble every one and clean up all the mating surfaces.

Good luck!


#21

B

BGS Mex

I'll let you know how it goes. This is how the Murray is wired.


#22

A

Auto Doc's

Hi BGS Mex,

I finally had a chance to print off the diagram and study it.

Print off the diagram that scrubcadet10 sent you.

The way I read the diagram, the "S" terminal white wire goes from the key switch to the clutch pedal switch and from there to the blade engage (attachment clutch) switch before it goes to the solenoid to trigger it for cranking the engine starter.

Just jumping the "B" red switch the "S" white wire at the switch will not crank the engine.

There is a clutch switch or blade engage switch or one of their connector pins that is having a problem. Possibly one of the switches are out of position. That is likely why you are having strange voltage readings, there is resistance/ voltage drop.


#23

B

BGS Mex

Auto Doc's said:
Hi BGS Mex,

I finally had a chance to print off the diagram and study it.

Print off the diagram that scrubcadet10 sent you.

The way I read the diagram, the "S" terminal white wire goes from the key switch to the clutch pedal switch and from there to the blade engage (attachment clutch) switch before it goes to the solenoid to trigger it for cranking the engine starter.

Just jumping the "B" red switch the "S" white wire at the switch will not crank the engine.

There is a clutch switch or blade engage switch or one of their connector pins that is having a problem. Possibly one of the switches are out of position. That is likely why you are having strange voltage readings, there is resistance/ voltage drop.
Click to expand...
Yes that is the way I have read the diagrams too. I have been doing my testing with both the Brake/Clutch and the Blade Interlocks closed. The white pins on each (tested at the conductor side) Have continuity to each other when closed and the green at the seat interlock (closed) has continuity with the green on the blade interlock and with the A2 (green) terminal on the ignition switch (on or off). It also has continuity to the L (Yellow) terminal on the ignition switch in the OFF position. The grey at the seat interlock has continuity with the grey on the Brake interlock. I am just finishing a complete summary of all the testing I have done to date and will send it when I have finished.
I agree completely with your "resistance/voltage drop". I just haven't been able to isolate it.Ignition Switch wiring Colors.jpg


#24

A

Auto Doc's

Can you connect a wire from the B terminal on the switch (with the battery connected) then touch it to the white wire pin on the solenoid to crank the engine? Key does not have to be on.

If it cranks that is bypassing everything and goes direct. If it does not crank, check the red wire for an issue getting power to the start switch. Trace the red wire back through all connections and verify they are clean and tight.

Also, I am not sure if the Husqvarna switch has the same internal pin contacts as the mower you are testing. Not all switches are the same internally.


#25

B

BGS Mex

Auto Doc's said:
Can you connect a wire from the B terminal on the switch (with the battery connected) then touch it to the white wire pin on the solenoid to crank the engine? Key does not have to be on.

If it cranks that is bypassing everything and goes direct. If it does not crank, check the red wire for an issue getting power to the start switch. Trace the red wire back through all connections and verify they are clean and tight.

Also, I am not sure if the Husqvarna switch has the same internal pin contacts as the mower you are testing. Not all switches are the same internally.
Click to expand...
Thanx again: I will try that this afternoon. I have tried a wire from the battery to the solenoid (White terminal) and the engine cranks. The Husqvarna switch has the same part number; I am used to this as parts usually aren't available here, so I have to be very careful. When I have a repair I make sure I have the correct parts diagram. I will be sending a PDF of my testing efforts.


#26

B

BGS Mex

Here is a report of the testing I have done. I will try to include all 3 documents. I will convert the other from word.

Attachments


  • July 23 2025 Murray Harness Connectors.pdf
    281.2 KB · Views: 3

  • July 23 2025 Unconnected Interlock Switches.pdf
    220.9 KB · Views: 2

  • July 23, 2025 Interlock Switch and starting issue Testing.pdf
    235.6 KB · Views: 2


#27

B

BGS Mex

BGS Mex said:
Thanx again: I will try that this afternoon. I have tried a wire from the battery to the solenoid (White terminal) and the engine cranks. The Husqvarna switch has the same part number; I am used to this as parts usually aren't available here, so I have to be very careful. When I have a repair I make sure I have the correct parts diagram. I will be sending a PDF of my testing efforts.
Click to expand...
The issue that I have is outlined in my testing documents. I get good voltage at the B (red) terminal and battery connection to the solenoid; but only 8.5 at the white (S) terminal. I will check this again when I try your suggestion.


#28

B

BGS Mex

Well Here I am again. The good news is that the key switch will turn over the motor. I have no idea why! I will start putting things back tomorrow and see how it goes. Thank you so very much for your input; it really has helped my thought process. This became so frustrating for me.
Please note attached;

Attachments


  • July 23 2025 Murray Tests.pdf
    137.2 KB · Views: 5




#29

A

Auto Doc's

Hello BGS Mex,

That fuse looks like an original and very weathered from age and exposure. It's been heated up a lot.

I hesitate to call victory yet because a fuse that has been repeatedly overheated. What this old fuse shows means it has had poor pin fit connections in the fuse holder. The fuse holder should be replaced as well.

It is never good to see a voltage difference below 10V when cranking but check against other similar mowers to see what you find.

Simple meter voltage testing and Ohm testing are what tricked you on this one. Yes, it has been a traditional method of testing for years, but there is one better for situations like this.

It is known as voltage drop testing. What is that? How is it performed? How can a meter show a reading on a single wire connection?

It is not a magic trick, but it is often not learned as other methods are.

There are many examples of this online and mostly performed on automotive applications, but the same thing applies to testing any mower starting or charging circuit for a voltage drop issue.

You are NOT measuring from power to ground; you are measuring actual power (voltage potential) loss on a single wire or cable connected from point A to point B. This is an easy way to also test for a poor battery post to cable end connections.

On this Murray mower design connect one meter lead to the battery positive terminal and the other lead to the "B" terminal of the switch, then try cranking (with plug wires off). See what your meter reads when cranking.

Here is an example at a rider battery with a corroded post connection:

Voltage drop testing rider mower - Search Videos

www.bing.com www.bing.com

Here is a file from the automotive All Data information that can help also:



#30

B

BGS Mex

Auto Doc's said:
Hello BGS Mex,

That fuse looks like an original and very weathered from age and exposure. It's been heated up a lot.

I hesitate to call victory yet because a fuse that has been repeatedly overheated. What this old fuse shows means it has had poor pin fit connections in the fuse holder. The fuse holder should be replaced as well.

It is never good to see a voltage difference below 10V when cranking but check against other similar mowers to see what you find.

Simple meter voltage testing and Ohm testing are what tricked you on this one. Yes, it has been a traditional method of testing for years, but there is one better for situations like this.

It is known as voltage drop testing. What is that? How is it performed? How can a meter show a reading on a single wire connection?

It is not a magic trick, but it is often not learned as other methods are.

There are many examples of this online and mostly performed on automotive applications, but the same thing applies to testing any mower starting or charging circuit for a voltage drop issue.

You are NOT measuring from power to ground; you are measuring actual power (voltage potential) loss on a single wire or cable connected from point A to point B. This is an easy way to also test for a poor battery post to cable end connections.

On this Murray mower design connect one meter lead to the battery positive terminal and the other lead to the "B" terminal of the switch, then try cranking (with plug wires off). See what your meter reads when cranking.

Here is an example at a rider battery with a corroded post connection:

Voltage drop testing rider mower - Search Videos

www.bing.com www.bing.com

Here is a file from the automotive All Data information that can help also:

Click to expand...
Thanx again! I am certainly not celebrating yet. There still is the issue (in the wiring) that I haven't found. As you have seen from my testing report; where I get about 8.5 volts on the "S" terminal whether it is the Murray or Husqvarna ignition switch (Installed on the Murray) with either switch installed on the Husqvarna I get 12.68 Volts at the same "S" terminal! The (Murray) "B" terminal shows 11.8 volts and the battery 12.7 volts. Yet when testing at the Solenoid (disconnected) White wire it reads 11.46 Volts! It almost indicates a switch issue; except for the difference when installed on a different mower. I will keep messing with it this afternoon. This is making me far behind on other services! I will re-check all this stuff! I don't understand how the "S" terminal on the switch can be 8.5 volts and the white at the solenoid be 11.46 (Maybe I'm going blind while reading the meter!)


#31

S

slomo

That fuse - heavily corroded terminals.

Check pin fitment as in should be very firm to insert. Should see scratches from the female connectors scratching the fuse legs on both legs. If no scratches, take pliers and gently smash the female connectors a bit. Easy here if you do too much, might not get the fuse it.

Looks as the yellow plastic has melted possibly. If so do a real good diag on all the wires and connectors. Look for melted anything.....


#32

A

Auto Doc's

I think some of the difference comes down to how the 2 machines are wired.

This Murray (white wire) has to pass through the two safety switches before it goes to the solenoid terminal to trigger it. One of those safety switches could be contributing to the voltage difference when a load is applied.

Disconnect the plugs so the rider will only crank. Set meter to the mV setting. Place you meter leads with one clipped to the battery positive, and then begin at the start solenoid white wire, crank and watch the meter reading. That will show you the true drop of the circuit. Work your way back following the diagram and check each pin at the safety switches. When the meter does not show a drop, go to where it does and there is your problem. If it still shows a considerable drop, it will be on B terminal part of the harness or its connectors/ connections.

Do the same for B terminal feed wire side, both sides of the fuse holder to verify the problem is not with a poor fuse holder pin. I'm still suspicious of that switch power supply wire and it's crimp connections. The power wire to the key switch is connected piggyback to the main battery positive terminal. Corrosion creeps in these and it will mess with the connections that even seem tight. Loosen clean and retighten the power wire and positive cable.

Corroded pins, a bad crimp or the switch itself will be the three suspects.

You would need the product label information off the Husqvarna to get a correct wiring diagram to see the differences. But I think you will pin the problem down doing the voltage drop test method described.

This method of testing seems tedious until you get used to it, but it will become second nature pretty quickly when dealing with issues like this. Ohm testing just tells you there is a wire there. Voltage drop testing tells you if the wire can actually carry a load without dropping it.

Hope this helps you.

There is a guy on You Tube named Dan Sullivan who is a Master Equipment Technician, and he goes into great detail about voltage drop testing. He has a semi-sour personality, but he knows electrical diagnostics from all directions possible.


#33

B

BGS Mex

slomo said:
That fuse - heavily corroded terminals.

Check pin fitment as in should be very firm to insert. Should see scratches from the female connectors scratching the fuse legs on both legs. If no scratches, take pliers and gently smash the female connectors a bit. Easy here if you do too much, might not get the fuse it.

Looks as the yellow plastic has melted possibly. If so do a real good diag on all the wires and connectors. Look for melted anything.....
Click to expand...
Thank you: The fuse is "normally firm" entering the holder. The latest is that the engine cranks and fires the spark plug whether the seat switch is compressed or not! Yes the engine and everything else is super clean.

Attachments







#34

B

BGS Mex

Auto Doc's said:
I think some of the difference comes down to how the 2 machines are wired.

This Murray (white wire) has to pass through the two safety switches before it goes to the solenoid terminal to trigger it. One of those safety switches could be contributing to the voltage difference when a load is applied.

Disconnect the plugs so the rider will only crank. Set meter to the mV setting. Place you meter leads with one clipped to the battery positive, and then begin at the start solenoid white wire, crank and watch the meter reading. That will show you the true drop of the circuit. Work your way back following the diagram and check each pin at the safety switches. When the meter does not show a drop, go to where it does and there is your problem. If it still shows a considerable drop, it will be on B terminal part of the harness or its connectors/ connections.

Do the same for B terminal feed wire side, both sides of the fuse holder to verify the problem is not with a poor fuse holder pin. I'm still suspicious of that switch power supply wire and it's crimp connections. The power wire to the key switch is connected piggyback to the main battery positive terminal. Corrosion creeps in these and it will mess with the connections that even seem tight. Loosen clean and retighten the power wire and positive cable.

Corroded pins, a bad crimp or the switch itself will be the three suspects.

You would need the product label information off the Husqvarna to get a correct wiring diagram to see the differences. But I think you will pin the problem down doing the voltage drop test method described.

This method of testing seems tedious until you get used to it, but it will become second nature pretty quickly when dealing with issues like this. Ohm testing just tells you there is a wire there. Voltage drop testing tells you if the wire can actually carry a load without dropping it.

Hope this helps you.

There is a guy on You Tube named Dan Sullivan who is a Master Equipment Technician, and he goes into great detail about voltage drop testing. He has a semi-sour personality, but he knows electrical diagnostics from all directions possible.
Click to expand...
Well; here is the latest! The motor cranks and fires whether the seat Interlock switch is compressed or not; or disconnected from the harness! It does the same with the operable Husvarna switch too. I will check out Dan Sullivan; Thanx.

Attachments


  • Thursday July 24, 2025 Motor Cranks and fires with seat switch on or off..pdf
    245.8 KB · Views: 1


#35

A

Auto Doc's

Is the brake/clutch pedal is locked down? On some models that will allow cranking without an operator in the seat to depress the seat switch.


#36

B

BGS Mex

Auto Doc's said:
Is the brake/clutch pedal is locked down? On some models that will allow cranking without an operator in the seat to depress the seat switch.
Click to expand...
Yup; Locked down. How could I ever find out
"On some models that will allow cranking without an operator in the seat to depress the seat switch."
Click to expand...
I also tried it with the Brake off (Nothing) and Brake on/Blade off; Nothing. My latest thought is the seat harness connector "Shorting plate". I want to confirm that when the Interlock is attached to the Harness and when the interlock is compressed the middle two pins are "no continuity" to each other. I've had it out of the connector a few times.


#37

B

BGS Mex

Well; now here is a development. I re-tested everything with the same results. All the (lawn Tractor) wiring schematics I've looked at are pretty useless in my opinion. I am used to looking at YAMAHA and others like the sample. Has anyone considered the "Blocking Diodes" in the wiring as shown? None of the diagrams show or refer to these. Nothing else make any sense to my small brain. Anyone know how to test for this??? Virtually all the youtube videos concentrate on how to bypass the interlocks; NOT how to properly diagnose issues with them. I can't let this thing go without operating as it was designed.

Attachments






  • Yamaha VX 700 Diagram.pdf
    352.5 KB · Views: 6


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