# Help tracking 72v short to chassis

**URL:** <https://community.electricforum.com/t/help-tracking-72v-short-to-chassis/30701>\
**Category:** GEM Forum\
**Created:** [September 26, 2026, 4:29pm UTC](https://community.electricforum.com/t/help-tracking-72v-short-to-chassis/30701 "2026-09-26T16:29:22Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![otismoon504](https://avatars.discourse-cdn.com/v4/letter/o/a88e4f/32.png) [@otismoon504](https://community.electricforum.com/u/otismoon504)\
**Post date:** [September 28, 2026, 10:32pm UTC](https://community.electricforum.com/t/help-tracking-72v-short-to-chassis/30701/21 "2026-09-28T22:32:24Z")

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@AssyRequired  
Status update:  
Got everything put back together after 23pin connector “rebuild”

- I tested from B- lug to chassis using voltage setting, got ~78.1v
- I tested from B- lug to chassis using LoZ setting, got ~20.4v
- Then switched back to voltage setting.
- Got ~78.1v on chassis BattOn
- Got ~78.1v on chassis BattOn & KeyOn
- **Got ~70.1v on chassis with throttle pedal almost completely down and wheels spinning, on jackstands**
- Tested the B+ lug while pedal down and was at packV

So, would this support the idea that the leak is from controller, motor or F/A wiring?  
Tomorrow, I plan to try to isolate the controller following your instructions from above.

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**Author:** ![otismoon504](https://avatars.discourse-cdn.com/v4/letter/o/a88e4f/32.png) [@otismoon504](https://community.electricforum.com/u/otismoon504)\
**Post date:** [September 30, 2026, 5:40pm UTC](https://community.electricforum.com/t/help-tracking-72v-short-to-chassis/30701/22 "2026-09-30T17:40:46Z")

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@AssyRequired @Inwo  
Update:

- I detached the controller from the mounting plate and insulated the rear of the controller with some cardboard. Essentially, it was completely separated from the chassis. Still had the packV from B- lug to chassis.
- Removed the F1 & 2 wires from controller to the motor. PackV still there.
- Removed the A1 & 2 wires and this corrected the issues. No more packV to chassis

I’m going to contact the guy who rebuild the motor and get his opinion. Maybe an insulator or something was damaged during shipping.

Anyone else have any suggestions?  
TIA!

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**Author:** ![AssyRequired](https://yyz2.discourse-cdn.com/flex030/user_avatar/community.electricforum.com/assyrequired/32/7621_2.png) [@AssyRequired](https://community.electricforum.com/u/AssyRequired)\
**Post date:** [September 30, 2026, 8:00pm UTC](https://community.electricforum.com/t/help-tracking-72v-short-to-chassis/30701/23 "2026-09-30T20:00:18Z")

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Suggestions for what?  
I think you pretty much isolated where your leak was coming from.  
Who rebuilt this motor? Yep -\>call him.

Armature is shorted to ground.Something is whacked with your motor.  
If you wanted to carry this further,  
Use your meter and check the A1 and A2 lugs directly. (ref motor case).  
Expect OL. (it should NOT have any connection).

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