Demonstrated Lightning

[Old MXer]

98 TXT 36V G3698 1101275
This began as an intermittent won't go problem leaving the boss & dog stranded in miscellaneous locations. By the time (sometimes before) I got to the site the problem had resolved itself & the cart would run fine for a few days.

It wouldn't fail for me so I decided to check the solenoid since I had a good spare. It was clicking but I thought there might be a problem on the hi amp side. I disconnected the battery plus cable & removed the controller cover. Then I put the plus cable back on so I could activate the solenoid. Since the problem was intermittent I decided to do a resistance check on the hi amp contacts. That's when I got a wrench between the lower nut on the solenoid battery plus stud & a crimp end of the ring connector on the negative side of the primary coil. That little black wire that is controller pin #2. A sustained lighting & smoke show for a few seconds. A senior moment forgetting that stud was hot.

A new solenoid & a reed switch got everything (as for as I can tell at this point) working up to the point of connecting pack cables to the solenoid.
This is probably pointless but is there any way to check out the controller without risk to what's working now?

[Old MXer]

Before ordering a new controller, & in clarification to my rambling above, my only question at this point is;
Is there a way to bench test a controller without special testing equipment?

[Old MXer]

I made a mistake in describing the wiring connections in the first post of the thread.

Of the two small black wires on the solenoid that I shorted to pack + , one goes to the controller B-, (not to pin position 4 as I previously stated) & the other goes to the backup beeper which was disconnected years ago.
The short probably also went through the solenoid coil & out the two small red wires. One to controller pin #4, the other to MS3 switch N/O.

The controller is probably burnt toast but I'd like to prove it before spending the bucks to replace it. Any suggestions for doing this would be highly appreciated. I also don't want to damage the solenoid circuit since its ok now.

I'll also check out the motor before going any farther.

[Old MXer]

Motor resistance check was good, but I wanted to run it.

Since access to motor studs is pretty restricted, I didn't disconnect the wires from the motor. I disconnected them from the FR & metered each wire to it's A or S stud using a long sharp probe. Got about .04 ohms on each. Then I measured each wire to the motor case & still got around .04 ohms on each one so no A/S studs were shorted to the case. This process didn't take long & also checked out my wires. It was easier for me than going under the cart & dealing with the tight spaces.

After that I Used the thread titled "Series Motor Test", but did it using the disconnected FR wires & my car jumper cables. I bolted the A2 & S1 wires together for the test. After the previous "lightning" I was pretty thankful when the motor ran ok.

I've gotten some very good advice & direction from several guys on previous posts.
Seems a little quiet on this one...

[Old MXer]

Correction: When I metered for A & S shorts to the motor case I got OL, not .04 ohms.

[Old MXer]

If the lightning demonstration story wasn't enough, I made several errors trying to explain what was going on. I don't blame anyone for not jumping in.

I was unfortunate enough to get Covid twice & the second time really did a number on brain function.

Testing everything I could didn't find anything wrong. The controller was the only thing I didn't test because I didn't want to risk damage to the motor or to the solenoid circuit.

I replaced the controller & all is good.