Toro Timecutter Electrical Issue

S

steve933

Forum Newbie
I have a SWX4250 74787 (the zero-turn with a steering wheel)--2015 model with serial 315001246. I used it 3 times already this season with no problems. Yesterday, when I tried to start it, there was just a click when I turned the key. I could see the engine move slightly as if it was getting power, but just not enough. Here is what I've done so far and conclusions I've reached:
- Battery is not the problem. Jumped the main solenoid terminals and the starter/engine turned strong
- Replaced the solenoid with another I happened to have. Same problem.
- Jumpered the seat switch and jumped the solenoid again and the engine cranked and kept running. Lowered the seat and drove the mower to the yard to begin mowing.
- Engaged the PTO and nothing happened. Engine kept running but blade did not spin up.
- Noticed that the brake switch had no effect. In fact, noticed later that it doesn't even illuminate when I turn the ignition switch from off to on. However, when I turn the switch to on, I do hear the brake actuator. When I turn the switch back off, I hear the actuator again a few seconds later. Brake switch light never illuminates.
- Using an ohmmeter, I checked that the brake switch, ignition switch, PTO switch, and both fuses at the panel are working properly
- 12V is present at the PTO common wire
- 12V is present between the red and black wires at the brake switch when the ignition is on
- Jumping the white and green wires at the brake switch did nothing
- 12V is present at blue solenoid coil wire when ignition is in start position only (starter clicks)
- At the battery, very little voltage drop (0.2V) when ignition is turned from off to start.
-With ignition in start position, solenoid battery input is 12.55V and nearly 0V on output to starter
- Bench-tested the solenoid with a separate power supply and it functions normally.
- Solenoid coil test (across green and blue wires): 0V in off and run positions. In start position, meter started to show movement briefly, then quickly went to zero.
- At the ignition switch: Red is 12V in any key position, orange is 12V in run only (0V in off and start); blue is 0V is off and run and 12V in start. Jumping red to orange and turning switch to start does nothing.
- Jumping blue solenoid coil wire/post to battery positive does nothing
- Green coil wire shows 0 ohms to ground when the ignition is on. While ignition is on, supplying 12V to the blue coil wire causes the starter to click and try to spin but it isn't strong enough.
- Green coil wire shows 2K ohms to ground with ignition off, 17 ohms in run, OL in start.

I'm thinking that last item is the most significant. Whatever is supposed to be switching the green wire to ground in start position doesn't seem to be working. I suspect whatever is causing that is also disabling the brake switch and PTO switch.

I welcome any opinions and suggestions for what to try next.

Thanks!
Steve
 
If you have 12VDC at the solenoid input side, but 0 VDC at the output side when you turn the key to start, you have either a bad solenoid or battery. Test the battery by connecting your meter leads to the battery and read voltage when trying to start unit. If it measures below 10VDC I would replace the battery. If you get a reading of more than 10VDC I would test output on the output side of the solenoid. Positive lead on the output solenoid and negative lead on the battery negative post. Read voltage with the key in the start position. Less than 10VDC I would replace the solenoid. Let us know what you find.
 
Rivets said:
If you have 12VDC at the solenoid input side, but 0 VDC at the output side when you turn the key to start, you have either a bad solenoid or battery. Test the battery by connecting your meter leads to the battery and read voltage when trying to start unit. If it measures below 10VDC I would replace the battery. If you get a reading of more than 10VDC I would test output on the output side of the solenoid. Positive lead on the output solenoid and negative lead on the battery negative post. Read voltage with the key in the start position. Less than 10VDC I would replace the solenoid. Let us know what you find.
Click to expand...
Thanks for your suggestions. I eliminated the battery and solenoid as the problem. Did some more testing this morning and concluded that the brake box assembly must have gone bad. It not only controls the brakes, but also is the start safety mechanism that prevents starting if it thinks things aren’t “right.” The tell-tale clue was the the negative side of the solenoid coil was not showing 0 ohms to the negative battery post when the switch was turned to start. I connected a temporary wire from battery negative and the coil negative post, turned the key to start, and it cranked just fine. Turns out the brake box assembly permits starting by providing proper ground to the coil. Until it does, the negative side of the coil, the PTO, and the brake switch all float. At this point everything points to a malfunction in the brake control box. I’ve ordered a new one. I’ll follow up after I install it.
 
Note check the module connector carefully if corrosion is present the wire harness must be repaired or replaced as they will not warranty the new controller if not done.
 
Thanks for the tip. No visible corrosion. I plan to add some dielectric grease to prevent moisture from getting in there going forward.
 
Thanks for the tip. No visible corrosion. I plan to add some dielectric grease to prevent moisture from getting in there going forward.
 
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