2902 gem car not getting the CLUNK

Dear Team,

My students at the high school I teach at , have redesigned and repurposed a 2002 gem e85 two seater. We are at the final stages and ran into a snag. We have brand new batteries, DeKa gels. When the master switch is turned on our BDI lights up and then goes blank. If you turn on the key it still stays blank, and everything electrical works. We just don’t get the CLUNK, that associates with any kind of movement. Any help would be greatly appreciated, trying to help the kids meet their target date. Playoff football game on Saturday, where the kids would show it off.


The controller is probably defective. How ever check the E brake switch.

As Rodney states, the main contactor is activated by the controller.
B+ must be connected to one side of coil.
The other side goes to “17 LINE CONTACTOR COIL DRIVER” which both checks for B+ level and brings pin 17 low to activate coil.

Other conditions must also be met.
Most importantly pins 1 & 2 have proper voltage. Other faults should then be displayed if controller is powered by 1 & 2.


Rodney is right of course. Check the e-brake. I am not familiar how this is connected on T4 cars.

I have the exact same problem on my 01 e825. Came here to find answers.

That is exactly what the guy at Just-For-Fun said right before he sold me a new controller. My controller is now brand new from Just-For-Fun, so I doubt that is it.
I am betting that @Rverone and I share the same solution, since we also seem to share identical problems.

Mine was doing the same thing. It was missing the green wire to the ignition relay and charger interlock wire.

Try this ,
Touch these two wires together. This will bypass the 12v part of the system.
Background shows where to remove these two wires from the ignition relay.
White is 72v +
Grey / white is key on to controller and power to direction switch.
Post results


The following error code appears…

  • 04

… actually it appears to read - n4

…but I believe one segment of the display is burned out, and it really means - 04.

Is this helpful?

Control will not operate; buzzer will sound.
Emergency brake switch input mis-adjusted or
• Input voltage at P13 should be less than
2.5VDC. Adjust or replace the brake switch to
insure that the voltage at P13 is less than
Open circuit between battery negative and P13
in the emergency brake switch input circuit.
• Disconnect wire from P13. Check for open
circuit between this wire and battery negative.
Defective controller.
• Voltage measured between P13 and
negative should be 4.5VDC. If not, replace

I got the clunk!

Parking brake it was. Strong now is the force in this car. @Rverone has similar results I hope!

Thanks @greengearhead😂. A Jedi Master you are.

Hello Gemmers.

I’ve got this same issue in my ‘02 e825. I bypassed the relay already and got the -04 error code. Which goes away after releasing the parking brake. I was told I need to replace the relay. Will someone confirm the issue is the relay. If it is, where can I get a replacement?



Any relay problem should throw a code. It is heavily monitored for function.
How were you able to bypass relay? Or do you mean the interlock relay?

I had a similar issue with a 2004 Gem except the contactor was going in and out and Rodney told me to check the parking brake switch, replaced the micro switch and now all is well!

I am having a similar problem. Batteries are good and charger is working properly. I turn on the key and get nothing on the BDI and get no clunk. When I release the brake it makes the loud beep. From working through the trouble shooting guide I think it is a bad motor controller but I am hesitant to pay like $500 for a replacement because I am pretty new to all this (first time posting) and lacking confidence in my diagnosis. Any suggestions for other things to test or other issues to check for before I start forking out cash??
Thanks in advance!

I have a 2002 with the same problem. No codes, no clunk sound, all accessories have power. Buzzer sounds when parking brake is released. My problem however is intermittent. The 2 times that I tried to diagnose the problem it suddenly fixed itself. Very hard to diagnose when it’s not doing it. My question to the experienced guys is can a controller fail intermittently?

If the cart sits for a long time continuity at the various connectors to the controller can cause issues. Always good to have clean and bright connections at each battery terminal as well at the other main connections.

Thanks for the suggestion. I guess I will remove all cables and make sure they have a good clean connection. Always good to start simple and work from there.

See if car is turning on. B+ on p1 and p2.
Common failure is dc converter and key switch.
I believe that 12v is required to power high voltage system.

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Thank you. I will check it out the next time it acts up. Intermittent problems are such a pain. I’m afraid I’m going to get stuck somewhere.
If the DC converter was failing then wouldn’t all of the 12 volt accessories be out?

I finally got stranded. The only difference between my last post and this time is everything is dead. Last time all 12 volt accessories worked. This time nothing at all works. Completely dead.
INWO suggested testing B+ on p1 and p2. I’m not sure where that is.
I followed the trouble shooting section in the service manual and got to step 6 in section 5-9.
It said to check the voltage at the B+ INPUT of the motor controller. I’m not 100% sure where the B+ is on the controller because the manual doesn’t say which terminal to check. I think it’s the large terminals on the top of the controller but it would be great if someone can verify this. If this is correct then the manual indicates that I need a controller because I have good voltage on the large terminals at the top of the controller. I don’t have confidence in my diagnosis so it would be great if one of the experienced guys could confirm that I need a controller.