M-1078 no dash lights

[tybaslee]

I have a 1995 LMTV with 15K miles. everything works except the lights in the cab. all exterior lights work as they should. I checked all the circuit breakers GTG. gauge lights, CTIS controller lights, lights for the heater are all not working. the transmission range selector and pod that shows air breaks and blinker indicators work. any ideas?

 

[NDT]

Are you familiar with all the functions of the 3 lever light switch?

 

[tybaslee]

Yes tried in all positions. I'm thinking the light switch that's not getting power to the gauge lights.idk

 

[NDT]

Just to eliminate the obvious, you have actuated up the left bottom light switch lever?

 

[Suprman]

Did you turn the dimmer knob on the dash?

 

[Ue413]

Hard to see them during day if you are not attempting at night

 

[tybaslee]

Yep done it at night

 

[tybaslee]

And yes to the other replies

 

[Suprman]

The dash lights are all on one circuit coming off the light switch going thru the dimmer. Use a multimeter and diagnose it. Light switch has to be on at least the first click. Left bottom switch needs to be all the way up. Be careful when you take the dash panel off the plugs come out of the trans ecu very easily and if you dont notice it, when you put the dash back together you wont be able to go anywhere.

 

[tybaslee]

That's my next stop. I have already had the Trans ecu issue. It took an hour and took the dash apart twice before I noticed it was unplugged

 

[tybaslee]

I also hear relays clicking when switching levers on the headlight switch.

 

[Suprman]

There are relays for headlights and a blinker module or relay. Check all of your relays. Some are 12v coil some are 24v. Some need the center terminal some don't. It's very confusing. You have 12v relays switching 24v and 24v relays switching 12v. You have to read the diagram on the back of the cover panel carefully.