2002 Gem e2 (No power)

The gem has been working good for a while and i came out today to go out and nothing happened when i turned the key on. I checked the master switch and it was on. I checked to see if the ignition wires were plugged in and yea… Nothing works…no horn, wipers, lights etc… no mileage. The only sound is when i take the e brake off it beeps…but that does that always does that when the key isn’t on.

Is it a controller problem? I checked the 2 10 amp fuses and the large 400…and they look good.

The car charges fine…green / orange / red light etc…

how many fuses are in the 2002 gem e2? I only see 2 red 10 amps and the 3 or 400 amp one? People keep talking about a “Fuse block” under the “hood” … i am guessing that is for a newer version?

Check the fuses on the DC/DC converter. Check the key switch wiring. There is a connector on the steering column. The red/green wire should always have 72 volts, unless the charger is plugged in. If not, the interlock relay in the charger may be bad. Does the charger come on when it is plugged in? A short jumper can be inserted between the two small wires that attach to the top of the charger. This jumper will bypass the relay and actually allow the GEM to be used with the charger removed.

If you have 72 volts into the DC/DC converter and the fuses are good, it may be bad. These have been superseded several times.


the charger looks to be charging like normal. Do you open up the DC converter to get to the fuses? What are the two red 10 amp ones on?

First, we need to find if 72 volts is getting to the DC/DC converter. There should be three fuses, a 10 amp, a 2 amp, and a 1/2 amp.


So the DC/DC converter opens up? It looks pretty sealed but I guess i will detach everything and test the volts as well. Thanks

I don’t seem to be getting any voltage. Am i testing the top terminals or where should i be testing?

that is the converter we are talking about right? lol… should i be testing the top of that for 72v? How does it open up to check fuses? Just unbolt it all?

Your photo is of the motor controller. The DC/DC converter is to the right of the motor controller and battery charger and is smaller than both. By tracing the 72 volt source wire as shown above, the circuit will lead you to the DC/DC converter.


ok my problem was that my multimeter blew a fuse. I am showing 75 volts everywhere i check…is that bad that it is 3 volts high? on controller, and both sides of the 400a fuse on the converter. I only see 2 10a (red) fuses on bottom right and the 1 400a fuse. Is there another fuse? Look at the pic below. Two in bottom right and then the big one. This is the DC converter right? Think there are any other fuses? or is it blown?

I connected the green and red wires going into the top of charger (i have done that before when i sent my charger to zivan) and it didn’t do anything. I checked the voltage to the ignition and it was 72+. I connected ignition wires together and nothing.

Can i just test for 12 volts coming out of the converter? Or does it read 72 always? I was getting 72 everywhere i checked.

Any converter recommendations? I saw this one

and you recommended the locomotive one…

Check also the single white wire on the converter that should be a constant 72 volt source. The single green wire next to the white wire is the ground. If you also have 72 volts at the orange / green wire at the converter, The converter is grounded to the chassis, and the fuses are good, it should be working. I have seen the plastic fuse holders melted from high loads. By looking at the schematic, this converter does a lot more than just reducing the voltage. Several other 72 volt and 12 volt circuits originate here. Retrofitting a converter may prove difficult.

The replacement converter shown will give 300 watts (25 amps X 12 volts = 300 watts) of power as opposed to 120 watts (10 amps X 12 volts = 120 watts). This is a big improvement in power for accessory power. There are several sources for these with 72 volt input because many diesel locomotives use a 72 volt battery system. Being waterproof is also important because the early converters were not and many caught fire. Both of our 2002 GEMs still have burn marks under the dash. We need to be sure the 72 volt primary wire from the key switch to the charger interlock and on to the converter will handle the extra power. This is the orange / green wire at the converter.

have you ever seen the replacement circuit boards / dc converters for sale? I am assuming i can’t get any recall work done in 2012 when it was posted in 07…

when the DC/DC converter isn’t working, does the car not start as well? The only thing i get when i flip the master switch is a quick 0000 on the dash and then it turns off. I get no power to any accessories (lights etc), and when i turn key i get nothing. If i take the e brake off with key on I get a loud constant beep. That’s about all the signs of life i get.

None of the 12 volt stuff would work with a bad converter. Call the factory with your VIN to find out about the recall.


[QUOTE=Susp3nc3;10294]I am assuming i can’t get any recall work done in 2012 when it was posted in 07…[/QUOTE]There are no expiration dates with recalls. If you have the old exposed circuit board style, they will replace it with the new potted version.

I have a 2000 E825 that loses all power but if you mess with the emergency brake wires it seems to come back on. CAN SOMEONE HELP

[QUOTE=robbiemann;11436]I have a 2000 E825 that loses all power but if you mess with the emergency brake wires it seems to come back on. CAN SOMEONE HELP[/QUOTE]

The parking brake contains an interlock relay that prevents the GEM from being driven with the brake on. This is a small reed type switch. The switch must be adjusted periodically, or the GEM will cut on and of while driving and especially when hitting bumps. The screws are very small and one of the holes is slotted to allow the switch to be moved. You should be able to pull up on the brake handle at least an inch before the large relay opens.


Hey Daniel I replaced that relay switch on parking brake it seems like the wires are it do you think it could be the key switch I mean when it loses power everthing goes out like you turn off the master switch

Check also the key switch and the battery charger interlock relay. Check the large plastic wire connector where the harnesses come together on the steering column. Trace through the circuit checking each length of wire for continuity. [B]Be careful. Both driving and working on the GEM with switches jumped out could cause the vehicle to take off unexpectedly.[/B] Be sure to raise the drive wheels and support them with jack stands.


Will do!
Thank You