2009 TXT no go

[JohnnieB]

Getting the solenoid to click is probably the first thing to fix. (The smoke may have came from the precharge resistor when the solenoid contacts didn't close and the motor tried to draw a bunch of amps through it.)

The solenoid's small terminal with the red wires on it should have 38V on it when a direction is selected on the F/R and the keyswitch is ON and the pedal is pushed. If it doesn't go searching for the voltage with the schematic kgsc posted.

[Powder Burns]

OK now I don’t get the voltage to pass through the pedal switch. So I took the microswitch out and the button is all kinds of floppy. I can’t get any connectivity across it regardless of the position. So I need a new one of these for sure.

Yeah, this worked before, but it could very well be that it was going in and out prior to completely failing, I guess. In any regards it does nothing now.

Any good source y’all recommend for such parts online? Is one of the site sponsors good for such things? I’d rather give them business than some random Amazon vendor.

The saga continues...

Also, regarding this from before:

Having 37V on B+ and M- indicates the throttle is wide open, or the speed "valve" in the controller is shorted

I confirmed that B+ and M- are equal to 37V (well, battery bank minus 0.7V) always. Key off, no accelerator pedal pushed. Just standard resting state.

[JohnnieB]

Yes one of the site sponsors would be a good choice.
https://www.buggiesgonewild.com/site-sponsors.php

The constant 37V between M- and B+ means there is a constant throttle signal telling the controller to run wide open, or the controller is bad.

Attached is how to check the throttle.

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If the controller is bad, replace it with an Alltrax SR48400 or larger.
https://www.cartsunlimited.net/alltrax-sr-series--.html

[Powder Burns]

OK I’ll replace the micro switch and then make those measurements. Hopefully it’s not a bad controller, as they seem expensive. Also FWIW I looked at the recommended Alltrax SR48400 and it looks totally different than the one in it now.

[JohnnieB]

If the Curtis 1206 is a 275A controller designed in the early '90s and if that is sufficient for your needs, that's good.

The SR48x00 uses more mordern technology, is user programmable and comes in 300A, 400A, 500A and 600A versions. It is used by cart owners that need more low end torque due to having taller than the sock 18" tall tires, or have rear seats on the cart, or haul heavier than stock loads, or some combination thereof. It is not plug-n-play, but it doesn't take much skill to install.

[Powder Burns]

Well, I replaced the micro switch. When the accelerator pedal is all the way out (not depressed), the switch is conductive. With just a little pressure on the pedal, it depresses the button on the switch and breaks conductivity. Further pressure gets past the large portion of the accelerator shaft and then conductivity starts again.

I don’t know if this is correct. It would seem that it’s out of adjustment and should not be conductive until the accelerator is at least somewhat depressed?

That all said, when conductive (pedal not depressed though, as above), I got instant smoke on the jumper on the red wire that burned up before. So I immediately turned off the go switch on the dash.

So this seems really bad. Would a bad controller cause this? I can’t test anything if I’m setting that red wire on fire when the circuit is closed...

This is getting rather frustrating, but I’ve got to get it fixed.

Ideas?

[JohnnieB]

Yes pedal switch shouldn't conduct when pedal is up. Here is the adjustments and a picture of a pedal box.

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There are two red wires on the solenoid, which one is getting hot? (Picture?)

also, try it with the white connector on top of the controller disconnected. The solenoid should click without to controller connected.

[Powder Burns]

Thank you for the pedal adjustment diagrams. When I get back out to the farm, I'll adjust it (the cart is on a farm that's a 45 minute drive from my house, so there is a lot of back and forth...).

Then I'll try again with the white connector unplugged from the controller.

If you look at the picture I posted before, it's the red wire that has the yellow wire nut on it. For today's test, I removed that and used a jumper with alligator clips on it. Both ends of the alligator clips started smoking.

From the jumper, the wire is one of the two going to the solenoid (95% sure). I'm not sure if that's what you wanted to know, though.

[JohnnieB]

That red wire goes from pedal switch to the solenoid coil and feeds the controller's electronics, so it's drawing a couple of amps. Maybe the jumper is too lightweight for the job.

Remove the diode from between the solenoid's small terminals, it might be shorted. (Solenoid will work without it, but should be there for normal operation. It protects the pedal switch contacts from the voltage spike the solenoid coil generates when it de-energizes.)

[BFF]

Originally Posted by JohnnieB

...



Remove the diode from between the solenoid's small terminals, it might be shorted. (Solenoid will work without it, but should be there for normal operation. It protects the pedal switch contacts from the voltage spike the solenoid coil generates when it de-energizes.)

(This is actually Powder Burns, but for some reason I can’t access that now so this I guess is my temporary alter ego....)

It took more than a week to check it out again, due to weather, work, and all kinds of distractions....

Well I removed the diode. With the controlled plug disconnected, I did get a solenoid click. So I attached the controller plug and when the pedal is depressed enough, the cart stated to move!

So it seems that I have a shorted diode. It meters zero volts in both directions with the meter in diode mode. Wish I’d checked that before....

So now to get a (couple) diode(s), adjust the pedal switch engagement, and put it all back together.

I’ll confirm if it works, but for now I have high hopes!

THANK YOU JohnnieB for your repeated help! I very much appreciate it, and I owe you a six pack of your favorite brew.