Oh heck, I've done it now. 12 volt? Anyone

Well, I have been totally redoing my litle 2002 E2. I had overheating problems, put in a heat sink and a fan. Was kind of actually proud of myself. (Not a lot of women diyers on this forum!) Also finished a custom stake bed that is darling. Put on new smaller wheels and really cute hub caps. I guarantee I’ve solved the -41 problem now.

But… I was installing a new radio, and accidently crossed the wires. Yikes! Fried the radio, burnt the 12 volt fuse. Okay, I can deal with that. Changed the fuse, new battery… But…my voltmeter doesn’t read 12 volts coming out of the purple wire for switched 12 volt power anymore. What did I do? Can I fix it? Thanks for any help. This forum is a lifeline for me.

(Truth - electricity really isn’t my thing, I’m an engineer, but I’m trying! :slight_smile:

What 12v converter is it? Sure power or the open circuit board?

Um, hmmmm… I’m using the purple wire that comes from the converter. Hmmm…just looked and it says sure power. Thank you for any help!

And I should add, even though my voltmeter reads “low” my fan on this same wire (it has 2 outlets) is running just fine. Things that make you go hmmmmm

Check your volt meter with a known good 12 VDC source (car battery) ! Converter may be damaged but still delivering some kinda chopped up waveform. Fan motor may run on it ok but a device needing some thing closer to pure DC may not. Be sure your volt meter is connected to the ground side of the converter directly - not just to the frame. Could have a bad ground connection some where.

Will the radio work ??

I’ll check tomorrow. Just got a new radio today. I’ve been using the negative of a 12v battery for the voltmeter. I will check against ground with the voltmeter tomorrow. Thanks for any and all suggestions!

You’re welcomed. I’m a new GEM owner - trying to learn the systems used on it
Am retired BSEE, but my first encounter with these little systems - dealt previously with mostly really big stuff! (2500+ hp) Mine is a 2008 eS. so the drawings I’ve rounded up may not apply directly to your machine. Most likely a corroded connection somewhere. Are you using a battery in the main battery bank for the ground ?? The main bank (negative) is not common with the 12 converter negative output on my eS.

I have a spare small 12 volt battery for the constant 12 volt charge. The newer gems have a source for both a constant and switched 12 volt. Old gems like mine, only have a source for a switched 12 volt.

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I believe all surepower have both 12v sources.

12 volt system is grounded to frame. 72 volt system ground is isolated from frame and uses wired return.

Understand that - but does she have a secondary 12 vdc battery as a “non switched” 12 vdc source ?? (2002 model). Also, is the Sure 72 to 12 vdc converter a chopper of some kind and what should the output wave form look like? How do they normally fail ?? There is one on my machine - along with a Quick Charge - onboard charger.


So, verified I really DID have 12 volt switched, measured to black ground, and it was correct. Wired up my radio, still nothing. Dang. Just had to set it aside for awhile. Dang.