Lost all my lights...

[gilby21]

Hey guys! I know there are a ton of electrical issue posts and I've been combing them. Even printed out the wiring diagram and taped it together and highlighted, but still can't find my culprit. I'm not an electrical genius, but I have a talented mechanical friend helping when he has time.

I've been building my Humvee for a couple years. Finally got it all painted late last fall and have been putting it all back together as time allows this winter. Recently, I installed my new headlights and blinkers and blackout light and side markers (all purchased from Midwest Military Parts). Upon install, everything worked perfect. Then it got super cold and I didn't spend much time in the shop through January/February. Two weekends ago, I went out to drive it for the first time since it was all back together and the batteries were dead. I put a charger on and get the rig going, but I had no lights. For a moment, I had blinkers and brake lights and cluster lights... and then nothing.

We took the switch out and disassembled. The breaker inside was popped. Also, the connection points were fairly wore down, so we removed the blackout light connection point and put it on the service drive side just to see if that was the culprit. We soldered a 40a fuse in and tried it all again. The lights flashed and then popped the fuse. Currently, we show .3 ohms on pin H, which says to 21, female end to service tail lights. So far can't find an obvious short or issues and when you unplug 21 on either side, nothing changes.

Curious if anyone has any ideas or has seen something like this. I know a lot of times it's the switch or the blinker. I do have a new 3 lever switch but with the issue of the .3 ohms, I don't want to melt the new $100 switch too bad. Would the light in the blinker lever be an issue?? We thought not with the reading currently. Hopeful someone has an idea of where to check cause I'm sorta lost at the moment. Thanks to all!

 

[HoveringHMMWV]

What type of light switch do you have with a CB?
Have you checked your grounds?
Have you checked for shorted or chaffed/damaged wires?

 

[NDT]

All 3 lever light switches have a self resetting circuit breaker inside. Sounds like you have a short to ground in a harness somewhere. Did a critter dine on your wires somewhere up underneath? You will need to trace out the circuits looking for sins.

 

[155mm]

H is service drive markers, so i would start there by disconnecting all the markers, front and rear since 21 is also 491 that services the front markers, and an ez unhook point is the hood harness bottom left and you disconnect the whole hood.

you can also disconnect the turn switch while trouble shooting to help find which circuit the dead short is on, then you could test headlights and horn only

the bulb in turn switch needs to be led if you replaced all your lights to led, and someone else will comment the engineering of why, something about electricity traffic jam going in both directions on an incandescent and the led makes electricity go one way?

also since you already disassembled the 3 lever, you could build your own test rig and not worry about smoking your new one, it also lists the pin out so you dont have to chase schematic lines https://www.steelsoldiers.com/threa...od-to-push-pull-switches.222782/#post-2602143

circuit breaker is listed on schematic and looks like this IRL

 

[gilby21]

Awesome. Thank you guys! I will disconnect the hood harness and try to determine if the issue is front or rear first. My side marker grounds I was curious about. The new markers I bought - one of the four install holes has the copper ring around it. It was a long time between disassembly and reassembly and I didn't take pics of all that, so I may have those grounds incorrect. I did check that once, but didn't make a difference on my ohm reading so I put it back.

In regards to the horn, I put an aftermarket steering wheel in. The oem wheel was broken in half and not real functional. I didn't re-install the horn with the new one. Don't really need it. Didn't really care. Only reason any man needs a horn is to honk whenever their wife walks in front of the vehicle! Not sure if no horn would be an issue, but I put that steering wheel on as one of the first things I did two years ago and everything worked accordingly until all this started.

If I remove the bulb in the turn switch all together (for testing purposes), would that cause an issue or false reading?

I guess that's why I'm confused. When I installed all of these lights (one at a time at separate times), everything worked perfect. Multiple times. Then all of a sudden, months later, nothing. If it wasn't grounded properly, I assume it would've melted that circuit breaker immediately, no? Not after multiple starts and tests. The truck certainly never moved so it was quite literally sudden and instant! And in regards to that circuit breaker, mine isn't like that picture. Mine is a metal plate looking piece and it pops up when triggered.

 

[155mm]

bulb must be in the turn switch to function