Electrical Assistance

[Assault King]

Afternoon folks,
I have all LED lights on the truck and they have been mostly fine. Recently, my right rear brake light and turn signal stopped working, but the running light functions. Didn't pursue the problem other than cleaning the ground wire. Now the left rear running light doesn't work, but brake and turn signal does.
Humvee sat outside and got absolutely soaked from a recent thunderstorm that rolled through, lights were working as of this morning but when I went to grab some lunch, I noticed a burnt electrical smell. Got home, absolutely no lights working. Looked in the manual and see where power should be coming from and long story short, my 3 position light switch and turn signal switch fried itself. What would have caused both components to do so if my generator is outputting the right voltage? If I left out anything, I apologize and will respond as soon as I can.

 

[Coug]

Sounds to me like you have an electrical short somewhere in the light circuit you need to hunt down.

 

[Assault King]

Sounds to me like you have an electrical short somewhere in the light circuit you need to hunt down.

Thank you for your input, wouldn't all shorts go to the nearest ground though? Not all the way back to those two components? Sorry, I'm a machinist, don't know much about electrical other than changing out a few drives, motor starters, thermal overloads, etc.

 

[Coug]

Thank you for your input, wouldn't all shorts go to the nearest ground though? Not all the way back to those two components? Sorry, I'm a machinist, don't know much about electrical other than changing out a few drives, motor starters, thermal overloads, etc.

Power comes from the batteries, through the headlight switch, then through the turn signal, and then goes out to the lights.
I believe it also comes through the PCB before the light switch.
There is a breaker inside the light switch that will not reset itself until the short circuit is taken care of, but that won't cause a burning smell.

If you have a short in the wiring near a light itself, the power still has to come through all the other components before it reaches the location of the short circuit.

When you say you have all LED lights, do you mean that you have the sealed LED fixtures, or that you have LED bulbs placed into the old housing buckets?
I ask because if you have LED bulbs in older housings, you will also need to pull apart every housing and inspect and test inside of them for possible shorts or open connections as well.

One piece of advice is always disconnect the batteries before connecting/disconnecting the Protective Control Box, otherwise you risk frying it and that is an easy $1k to replace.



Here is a link the the HMMWV manuals for 3 speed and 4 speed non-turbo trucks (I assume you have a 3 speed from your avatar)
I don't know if you have downloaded them yet, but finding the lights troubleshooting section in the manuals ending in -20 would be a very good place to start your troubleshooting and potentially save you a lot of time and money in figuring out exactly what failed.

TMs for the M998-Series HMMWV

Listed below are a number of the TM's for the M998 series trucks. To save them to your computer, right click, select "save as". TM-9-2320-280-34.pdf TM-9-2320-280-34 Direct support and general support maintenance for the M998 series trucks. TM-9-2320-280-20-1.pdf TM-9-2320-280-20-1...

steelsoldiers.com

one other thing, I find it unusual that both the light switch assembly and the turn signal assembly would fail at the same time, so unless there is something obvious about them such as they both have smoke pouring out of them, I find it more likely that the issue is either a short circuit somewhere else in the system, or you have a bad wire between the PCB and the light switch assembly that caused the complete light failure as well as the burning smell when that wire burned up. The fact that it was raining heavily at the time this all happened would lead me to believe it's a wire issue similar to the one in this thread below, where a wire corroded and finally failed

HMMWV no lights at all ???

My m998 that I got from Govplanet has no lights anywhere,I replaced the headlight switch with 4 other switches,and replaced the turn signal switch.Does anyone know what wire is the supply wire to the switch ?Also the is 1 wire coming out of the headlight switch harness that is cut,but I cant...

www.steelsoldiers.com

 

[Assault King]

Power comes from the batteries, through the headlight switch, then through the turn signal, and then goes out to the lights.
I believe it also comes through the PCB before the light switch.
There is a breaker inside the light switch that will not reset itself until the short circuit is taken care of, but that won't cause a burning smell.

If you have a short in the wiring near a light itself, the power still has to come through all the other components before it reaches the location of the short circuit.

When you say you have all LED lights, do you mean that you have the sealed LED fixtures, or that you have LED bulbs placed into the old housing buckets?
I ask because if you have LED bulbs in older housings, you will also need to pull apart every housing and inspect and test inside of them for possible shorts or open connections as well.

One piece of advice is always disconnect the batteries before connecting/disconnecting the Protective Control Box, otherwise you risk frying it and that is an easy $1k to replace.



Here is a link the the HMMWV manuals for 3 speed and 4 speed non-turbo trucks (I assume you have a 3 speed from your avatar)
I don't know if you have downloaded them yet, but finding the lights troubleshooting section in the manuals ending in -20 would be a very good place to start your troubleshooting and potentially save you a lot of time and money in figuring out exactly what failed.

TMs for the M998-Series HMMWV

Listed below are a number of the TM's for the M998 series trucks. To save them to your computer, right click, select "save as". TM-9-2320-280-34.pdf TM-9-2320-280-34 Direct support and general support maintenance for the M998 series trucks. TM-9-2320-280-20-1.pdf TM-9-2320-280-20-1...

steelsoldiers.com

one other thing, I find it unusual that both the light switch assembly and the turn signal assembly would fail at the same time, so unless there is something obvious about them such as they both have smoke pouring out of them, I find it more likely that the issue is either a short circuit somewhere else in the system, or you have a bad wire between the PCB and the light switch assembly that caused the complete light failure as well as the burning smell when that wire burned up. The fact that it was raining heavily at the time this all happened would lead me to believe it's a wire issue similar to the one in this thread below, where a wire corroded and finally failed

HMMWV no lights at all ???

My m998 that I got from Govplanet has no lights anywhere,I replaced the headlight switch with 4 other switches,and replaced the turn signal switch.Does anyone know what wire is the supply wire to the switch ?Also the is 1 wire coming out of the headlight switch harness that is cut,but I cant...

www.steelsoldiers.com

Thank you for the lengthy response. I opened up the turn signal housing and light switch housing and visibly saw the burnt cable ends and burned wire sheathing. I did replace the old burnt up PCB with a camotek system box when I fiest got the truck, also cleaned all of the grounds front to back. All the LEDs are sealed housings, not plug ins. I did download the manuals and have been meaning to download the electrical schematic on our blueprint printer at work so I can have an enlarged copy lol. Might let the truck sit til the weekend before hunting down the potential short. I just find it odd that it both knocked out the turn signal and light box.

 

[Mogman]

Thank you for the lengthy response. I opened up the turn signal housing and light switch housing and visibly saw the burnt cable ends and burned wire sheathing. I did replace the old burnt up PCB with a camotek system box when I fiest got the truck, also cleaned all of the grounds front to back. All the LEDs are sealed housings, not plug ins. I did download the manuals and have been meaning to download the electrical schematic on our blueprint printer at work so I can have an enlarged copy lol. Might let the truck sit til the weekend before hunting down the potential short. I just find it odd that it both knocked out the turn signal and light box.

The brake light and turn signal power goes through the light switch and the turn signal switch so I would start there.