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Hi Troops,
Replaced the engine on my TC 2 weeks ago but the previous cranking problem is still bugging me!!! So today I took a color coded copy of the electrical system and with the use of three digital multimeters and assorted jumper wires, I diagnosed the cranking problem to be the Interlock Module. I went on line and did a search with "scag 483029", which is the part number of the Interlock Module and I found that this module has been problematic and superseded to Scag P/N 483599. Evidentally there has been a problem with the 483029 module and it showed up when it receives all the correct cranking circuit inputs and then supposed to send voltage to the starter solenoid which in turn sends high amperage to the starter motor. This module is found on the vast majority of Scag mowers both zero turn riders and walk behind units.
So, if any of you have a machine with a cranking problem, check the part number on the grey plastic module and if it is 481808 or 483029 and you have an engine cranking problem, this module may be the problem.
The replacement module for 483029 is 483599 and is pricey, but I'm need to buy one as my machine is out of warranty with the exception of the new engine and the intermittent cranking problem is starting to "blow up my Kilt" so to speak!!!:smiley_aafz:
Mad Mackie in CT:laughing::biggrin:

So, I went to my local Scag dealer and bought a new Interlock Module, installed it and the cranking problem appeared to have been taken care of, so Mad Mackie was a happy camper!!! However after a while the intermittent cranking problem reappeared!!!I went over and asked my neighbor to assist me in troubleshooting the electrical system as four hands and two somewhat electrical savvy minds are better than one!!! After a complete system checkout, we started jumpering out components one at a time from the key switch all the way thru to the starter solenoid. Under the panel with the throttle and choke levers, and keyswitch, is a relay that is part of the engine cranking circuit. We started to suspect that this relay was the problem and I had a similar relay in my parts stash, so I plugged it in and the cranking problem went away!!! Switched back to the old relay and the cranking problem returned. I have a set of Zona hobby saws and I cut the old relay open to see what was ailing it and I found that it wasn't closing the contacts every time I put power to it. Tomorrow I will go back to the Scag dealer and buy a new relay or maybe two as I like to have spare parts in stock for my working machines, of course I now have a spare Interlock Module at $109 but education costs money!!!! HaHa!!! The Scag relay has a diode installed in it, not sure why, but my stash spare was a basic relay without a diode.
So, tomorrow I wil give you all the rest of the rest of the story!!!!:laughing:
Mad Mackie in CT:laughing::biggrin:

Now the rest of the story!!!
Bought a new start circuit relay, installed it and the starter solenoid clicks every time. Reconnected the cable to the starter motor, inspected all where I had been tinkering and started the engine. I put a voltmeter on the battery to check the charging system voltage and no rise in voltage. Removed the engine blower housing so I could get to the regulator wire connections, disconnected the regulator wires and checked the stator which was OK. Fortunately I still have the old engine , so I removed its regulator and installed it on the new engine. Started the engine an voltage at the battery went right up to 14.35 VDC!!! So Mad Mackie is a happy camper with the Scag Tiger Cub up to 100% again!!!:laughing:
I'll do the new engine 5 hour oil change some time today and service the entire machine.
I'm going to order two Signal Dynamics digital charging system monitor meters and install them on the Tiger Cub and my Ingersoll 4018 GT. I should order three and install the third on the Hustler X-ONE.
Mad Mackie in CT:smile::laughing::biggrin:

Signal Dynamics charging system monitor link
Signal Dynamics | Signal Dynamics Corporation 1-800-785-1814 | Motorcycle Safety Lights | Break Light Signal Module | Motorcycle LED Lighting | Signal Dynamics - Creator of BackOFF
Mad Mackie in CT

Mad Mackie said:

Now the rest of the story!!!
Bought a new start circuit relay, installed it and the starter solenoid clicks every time.
Mad Mackie in CT:smile::laughing::biggrin:

Click to expand...

Mackie....thanks for all of this insight into the Interlock Module and the Relay Switch. I am curious to know if your final verdict was that the bad relay was the problem here. Did you ever try putting the old interlock module back in after you replaced the relay?

Thanks for all the help.

GW

Yes I still have the original electronic control module on my TC. The cranking relay was my problem and I keep a spare in my stash.
Another situation came to my attention a while back and it is the path of the charging system output which goes thru the key switch and when in the off position, isolates the charging system from the battery which on engines from the mid 80s and older, was necessary to prevent the charging system from discharging the battery when the engine was not running.
Now on most small engines, the regulator/rectifier internally provides isolation protection and thru a fuse can be directly connected to the battery.
Scag still wires the Tiger Cat and Turf Tiger machines with the charging system output passing thru the keyswitch, but has direct wired the charging system output on the new models such as the Freedom Z and Cheetah.
Since I've rewired my Tiger Cub, the system voltage has increased some and I feel that overall, the electrical system is functioning better.

Mad Mackie said:

Yes I still have the original electronic control module on my TC. The cranking relay was my problem and I keep a spare in my stash.

Click to expand...

Thanks for the quick reply on this old thread Mackie. I have really battled trying to get this issue resolved. The engine will start and run if I bypass the safety system.

Having tested the key switch in every position, all safety switches individually as well as at the interlock module plug, I then replaced the relay switch. I found out that I am not getting a ground coming out of the interlock module. As I understand it, the interlock module only provides a ground if all the safety systems are compliant.

I confirmed power from the key switch on the green wire to the relay switch, but I did not hear a click in the relay. I then bench tested the new relay switch and confirmed 85+86 clicks and confirmed that 87+87a connect (have continuity) on the click. This was true of the old relay switch as well, but I wanted to eliminate the diode from being the problem, so I replaced the relay with a new one.

Recognizing that I am getting no ground out of the interlock module (green/blk) to activate the relay, I pulled the green/black wire out of the module plug and ran a jumper from my negative terminal on the battery to it. My goal was just to see if the relay would click. However, somewhat to my surprise the engine started up and runs fine. Keep in mind that the interlock module is not even on the machine right now. While it was running I also confirmed on the amp meter that it is also throwing a full charge.

So, with this bit of information, having tested all the switches, all the way to to the module plug, and now confirming that the engine starts and runs without the interlock module in place, am I safe to conclude that the interlock module is faulty?

I want to order a new one if it is, but welcome your input to advise of anything else that I should check. Also, aside from the obvious safety hazards, are there any other mechanical/electrical concerns with running the motor without the safety interlock module in place?

Thanks,

GW

Mad Mackie said:

So, I went to my local Scag dealer and bought a new Interlock Module, installed it and the cranking problem appeared to have been taken care of, so Mad Mackie was a happy camper!!! However after a while the intermittent cranking problem reappeared!!!I went over and asked my neighbor to assist me in troubleshooting the electrical system as four hands and two somewhat electrical savvy minds are better than one!!! After a complete system checkout, we started jumpering out components one at a time from the key switch all the way thru to the starter solenoid. Under the panel with the throttle and choke levers, and keyswitch, is a relay that is part of the engine cranking circuit. We started to suspect that this relay was the problem and I had a similar relay in my parts stash, so I plugged it in and the cranking problem went away!!! Switched back to the old relay and the cranking problem returned. I have a set of Zona hobby saws and I cut the old relay open to see what was ailing it and I found that it wasn't closing the contacts every time I put power to it. Tomorrow I will go back to the Scag dealer and buy a new relay or maybe two as I like to have spare parts in stock for my working machines, of course I now have a spare Interlock Module at $109 but education costs money!!!! HaHa!!! The Scag relay has a diode installed in it, not sure why, but my stash spare was a basic relay without a diode.
So, tomorrow I wil give you all the rest of the rest of the story!!!!:laughing:
Mad Mackie in CT:laughing::biggrin:

Click to expand...

Hi Mackie, have cranking problems also on one of my 2003 cubs. Installed a new ignition switch, problem persists. Removed throttle panel to expose components. With key in cranking position, tested parking brake safety switch which made relay click. During this procedure the throttle panel accidentally came in contact with the tractor frame and engine cranked. Tested this several times and cranked each time. Don't know if relay has lost ground...must troubleshoot more...but already ordered another relay...so I guess will figure it out this week. The relay grounds via ground wire within harness yet engine cranks when panel touches metal ground...go figure?

glwilliams58 said:

Thanks for the quick reply on this old thread Mackie. I have really battled trying to get this issue resolved. The engine will start and run if I bypass the safety system.

Having tested the key switch in every position, all safety switches individually as well as at the interlock module plug, I then replaced the relay switch. I found out that I am not getting a ground coming out of the interlock module. As I understand it, the interlock module only provides a ground if all the safety systems are compliant.

I confirmed power from the key switch on the green wire to the relay switch, but I did not hear a click in the relay. I then bench tested the new relay switch and confirmed 85+86 clicks and confirmed that 87+87a connect (have continuity) on the click. This was true of the old relay switch as well, but I wanted to eliminate the diode from being the problem, so I replaced the relay with a new one.

Recognizing that I am getting no ground out of the interlock module (green/blk) to activate the relay, I pulled the green/black wire out of the module plug and ran a jumper from my negative terminal on the battery to it. My goal was just to see if the relay would click. However, somewhat to my surprise the engine started up and runs fine. Keep in mind that the interlock module is not even on the machine right now. While it was running I also confirmed on the amp meter that it is also throwing a full charge.

So, with this bit of information, having tested all the switches, all the way to to the module plug, and now confirming that the engine starts and runs without the interlock module in place, am I safe to conclude that the interlock module is faulty?

I want to order a new one if it is, but welcome your input to advise of anything else that I should check. Also, aside from the obvious safety hazards, are there any other mechanical/electrical concerns with running the motor without the safety interlock module in place?

Thanks,

GW

Click to expand...

Would like to know in detail exactly how to bypass the safety system...would rather do without it.

Mad Mackie said:

Yes I still have the original electronic control module on my TC. The cranking relay was my problem and I keep a spare in my stash.
Another situation came to my attention a while back and it is the path of the charging system output which goes thru the key switch and when in the off position, isolates the charging system from the battery which on engines from the mid 80s and older, was necessary to prevent the charging system from discharging the battery when the engine was not running.
Now on most small engines, the regulator/rectifier internally provides isolation protection and thru a fuse can be directly connected to the battery.
Scag still wires the Tiger Cat and Turf Tiger machines with the charging system output passing thru the keyswitch, but has direct wired the charging system output on the new models such as the Freedom Z and Cheetah.
Since I've rewired my Tiger Cub, the system voltage has increased some and I feel that overall, the electrical system is functioning better.

Click to expand...

Tinkered with the throttle panel again removing all connections, cleaning then re connecting and it started right up/ That seemed to have solved the problem for now...will keep you posted. Now have a spare ignition switch and relay, chances are I'll need them later.:laughing:

Posted this to another thread just now. I am having almost the same problem as yours. What do you think??


"I have a scag wildcat 52" (prior 2011 model, I will get a VIN asap) with a similar issue. Same thing where someone previous did play with some wiring. My issue is that I have intermittent power to the blade pull switch and NO power at all with the key in any position. When I say no "power" I mean that it is dead and does NOTHING...I replaced the ignition and clean all connections, replaced both fuzes, checked all safety switches for continuity (all came back good), I haven't found any wires so far grounding out or that are severed. There is a ballast resistor I believe that it on the side of the engine next to the starter, checked it for continuity and it has it. There is something similar (some type of resistor or module?) on the left side if you are sitting on the mower that has about 8-10 wires going into it and it is sealed with a gel/tar. I believe it is number 17 on page 66 of this manual. Is there a way to test it? What problems could that part produce?

http://www.scag.com/OPManuals/STWC/2...273 Rev2.pdf

Also, number 9 in the same picture is a relay. Might be having issues with it, maybe not. I made jumper wires and wired around it in efforts to get off a job site with intermittent success so it leads me to think it might not be an issue... I have to admit that I am totally lost here... Has anyone had similar issues? Thanks in advance!"

Hello everyone. I was searching the internet and found this thread to be the best resource in trying to solve the same problem I had. Thanks for all the great information, it helped me finally figure this one out.

I have a 2003 tiger cub 48 that had intermittent starting problems and I will tell you what I did to fix the problem. Turning the key I would hear a click, sometimes not at all. Sometimes it would start fine, other times not. What I nightmare I had throwing parts at this but I think the problem is finally solved, fingers and toes crossed.

Suspecting it was the starter/solenoid because it appeared to overheat, I replaced it and it seemed to work again for awhile and then the same problem returned a couple weeks later. I replaced the ignition switch and relay with diode under the throttle control panel, even though both were probably fine. One of the two -20 amp fuses seemed to be malfunctioning and I replaced both of them also, but still the same problem again. All safety switches appeared fine, (the one under the seat seems to get the most work out). I had the old interlock module and replaced it with the new one and this baby now seemed to be working great... until the problem returned when I shut the mower down and tried to start it again!:ashamed: I noticed the solenoid was red hot again for some reason and the battery terminals and connections looked like they had a work out. Checked the battery and it was only 11.8 volts.! So looking carefully I figured out what was actually happening. My battery was discharging when I was operating the machine. Faulty charging system, regulator?, nope.

My problem actually began when I replaced my battery at the start of the last years new season. It was shorting across the terminals because it would come in contact with the underside the seat. This nightmare started when I decided to increase my battery to a 335 CCA from a 225 CCA, big mistake! Even though these batteries look almost identical, the 335 CCA is 1/8" taller. I found out the battery cannot be any bigger that 6" tall, the 335 CCA batter was 6 1/8" which was just enough for the top of the terminals to come in contact with the metal seat every time the mower bounced and hit a bump! It was shorting even though I had the positive terminal semi-insulated. So here is what I did, I bought a new 6" tall battery with 225 CCA, 2 new terminal insulators, and now everything is all good. So after hundreds spent, I think the problem is finally solved. So with that, make sure your battery is the correct height and not shorting across the terminals like mine, expensive lesson!!! The interlock module and a fuse could have been a contributing factor to my problem, but I will never know for sure if they were agitated by a shorting battery.

I will check in later to update. Best of luck to anyone who has this problem.

Great "no crank" troubleshooting thread Thanks Mad Mackie and to Scagmaniac for updating and providing your experience..

I also had the sometime no crank issue on my 2014 Cheetah. Threw a lot of parts at it like battery, switches, relays. I finally bought a module and found a bad connection while replacing the module. I fixed the connection in the connector and left the old module on the mower. So far, mower has started every time, hot or cold. This is the longest I have gone without a no start occurrence. I am hopeful it is finally fixed. The cheetah is a great mower if it will start.

Big thanks to mad mackie!!!! I have this same problem of intermittent starting on my tiger cat. It finally blew a fuse and would not start at all.
Fortunately, I found this forum before I started buying parts. Changed the relay and fuse and it started right up.

glwilliams58 said:

Thanks for the quick reply on this old thread Mackie. I have really battled trying to get this issue resolved. The engine will start and run if I bypass the safety system.

Having tested the key switch in every position, all safety switches individually as well as at the interlock module plug, I then replaced the relay switch. I found out that I am not getting a ground coming out of the interlock module. As I understand it, the interlock module only provides a ground if all the safety systems are compliant.

I confirmed power from the key switch on the green wire to the relay switch, but I did not hear a click in the relay. I then bench tested the new relay switch and confirmed 85+86 clicks and confirmed that 87+87a connect (have continuity) on the click. This was true of the old relay switch as well, but I wanted to eliminate the diode from being the problem, so I replaced the relay with a new one.

Recognizing that I am getting no ground out of the interlock module (green/blk) to activate the relay, I pulled the green/black wire out of the module plug and ran a jumper from my negative terminal on the battery to it. My goal was just to see if the relay would click. However, somewhat to my surprise the engine started up and runs fine. Keep in mind that the interlock module is not even on the machine right now. While it was running I also confirmed on the amp meter that it is also throwing a full charge.

So, with this bit of information, having tested all the switches, all the way to to the module plug, and now confirming that the engine starts and runs without the interlock module in place, am I safe to conclude that the interlock module is faulty?

I want to order a new one if it is, but welcome your input to advise of anything else that I should check. Also, aside from the obvious safety hazards, are there any other mechanical/electrical concerns with running the motor without the safety interlock module in place?

Thanks,

GW

Click to expand...

Great thread as it has been very helpful to me since I am going through a very similar issue (which I have not yet resolved) on my Scag Wildcat (early 2000's model). Quick question in regards to this post -- how would I check and/or determine if the interlock module is providing (or completing) the ground through the green w/ black stripe wire??? Is there a way to test if I am getting the necessary ground at the ignition relay switch? I have a multi-meter, but am not yet great with using it. Would a continuity test allow me to determine if the ground is being completed? Thanks.

scagman2 said:

Would like to know in detail exactly how to bypass the safety system...would rather do without it.

Click to expand...

Did you find out how to bypass the electronic module , safety system . . I'd like to know how also and have you had any problems since .

1bobo# said:

Did you find out how to bypass the electronic module , safety system . . I'd like to know how also and have you had any problems since .

Click to expand...

As a matter of principle the site members will rarely advise any one how to bypass inbuilt safety switches weather we believe they are a good idea or not.
I for one feel the only switch that should be retained is the seat switch but there is no way i will advise any one on how to bypass any others.
You could be a very responsible person who checks the lawns for things like electrical cable & wires then makes sure there are no people outside & you todlers ( & the neighbours todlers ) are all safe inside before you start your mower.
However this is an open forum so any totally irresponsible idiot can then access the same information then cross post it everywhere because to the really stupid bypassing every safety device is a blow for the freedom of the individual .

If you have a specific problem then we will be happy to assist with the diagnosis.
Scags tend to use a complicated interlock module intergrated with the hour meter and it is quite difficult to bypass it .
And the more people who do bypass it then the more complicated the switches become
he more complicated the switches become the more prone they are to failure
So you end up in a never ending spiral of more expensive modules that are less reliable

Now I did not mean to sound like a preacher but that is just how things are every mower that leaves the workshop leaves with all of the sfety switches working weaher they have been deliberately dissabled by the owner or not .