M998 No Brake/Head/Turn/Marker Lights

[FunVee]

Been troubleshooting a lighting issue on my, new to me, M998A0. Hoping the collective knowledge here can accelerate my process. Found a couple very helpful threads, linked below and been working my way through the TM's. Hopefully, one of you can point me to a common gremlin or two I can check on.

Here's what i have done. Installed new grounding harness and cleaned up all grounds it touched. Generator is charging fine. Truck starts/runs/drives fine. Dash lights, wait light and brake light work as expected. I have tried two new Tri-Switches, made zero difference. Continuity through them is fine for all positions. I have 24v at pin F on the connector to the tri switch. The tri-switch plug is clean and in good condition. I opened up the tail lights, bulbs look ok. I do not have voltage at the lights.

So far the troubleshooting is pointing met to the PCB or tri-switch. Tri-switch seems fine and PCB is giving me 24V at pin F.

Any thoughts? Thank you in advance for you help.


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[springer1981]

Been troubleshooting a lighting issue on my, new to me, M998A0. Hoping the collective knowledge here can accelerate my process. Found a couple very helpful threads, linked below and been working my way through the TM's. Hopefully, one of you can point me to a common gremlin or two I can check on.

Here's what i have done. Installed new grounding harness and cleaned up all grounds it touched. Generator is charging fine. Truck starts/runs/drives fine. Dash lights, wait light and brake light work as expected. I have tried two new Tri-Switches, made zero difference. Continuity through them is fine for all positions. I have 24v at pin F on the connector to the tri switch. The tri-switch plug is clean and in good condition. I opened up the tail lights, bulbs look ok. I do not have voltage at the lights.

So far the troubleshooting is pointing met to the PCB or tri-switch. Tri-switch seems fine and PCB is giving me 24V at pin F.

Any thoughts? Thank you in advance for you help.


HMMWV A1 Troubleshooting | SteelSoldiers

m998 no lights | SteelSoldiers

HMMWV no lights at all ??? | SteelSoldiers

Sent you a PM

 

[FunVee]

Sent you a PM

Found the issue. Opened up the dash and found wire 79A, a ground, disconnected. No idea why, but someone replaced the ringeye on another ground and left this one disconnected. Cleaned up the ground screw, two other grounds, hooked them up and all the lights worked. I think one of my tail lights has an iffy ground, it flutters, but everything works. Thanks to @springer1981 for a phone call, too. He did a great job walking me through the electrical system, indirectly leading me to the fault.
Now on to the next project, the idler arm is worn. Replacing it next.