HIYA! LMTV turn signalsand brake lights not working (when pressed)

Hiya! I have a 1998 1079, and the turn signals, and brake lights dont activate when triggered, anyone have any tips? TY!

Is the light switch set to “service drive”?

Yep. Have to turn the lights on. All military vehicle start out in "light discipline" mode. You don't even get blackout drive unless you select it. On the pushbutton switch you press any button to wake it up and then your desired mode and enter.

If you have service drive turned on and they still don't work.... Clean every ground in the truck (there's over 100), replace all the old style circuit breakers with blade fuses, replace all the relays with appropriate NEW 12v or 24v five pin relays and then report back results.

Turn signal stalks do fail. Have seen that multiple times. Also the pushbutton switches on the A1+ trucks can and do fail - usually because they have a poor ground either at their dedicated ground wire (lever switch does not have) or the PDP ground in the passenger grab handle or the cab ground behind the radiator (particularly naughty) or one of the MANY other grounds that likely need serviced badly.

Or for us 3 lever crowd, release the lock and rotate the left hand lever to service drive to power brakes and signals… beyond that here is a basic lighting diagram. Full details and component and wire numbers are in the official electrical diagrams in the back of every manual…

AWESOME thank you yall! Ok the stalk does activate lights high and low beam, I got it to service, all lights work (stationary ones) but blinkers dont, one thing I noticed as well... there is no Switching clicking noises from the panel with relays...
im gonna start there first, and that you yall! I just put new head lights on and I will be converting it heavily to the (Drive the Globe) style military truck., will uplaod pics soon

The oem solid state flashers are a pretty high failure item, and this design has the flasher pulsing 100% of the time. Y0u can disconnect it(under passenger dash) and put a jumper across pin A-B which, if power is available on pin A, will send power thru the rest of the circuit for testing. I replaced mine with a commercial 12A unit made by grote…

The only thing that clicks in the signal circuit are K30 and 31, but these are for 24v trailer power and no-one I know has a 24v commercial semi-trailer. K06 and K10 should go click when you step on the brake pedal(must be air in the tanks to activate the pressure switches on the treadle valve…

Hiya yall ty, so I think the previous owner did some Janky wiring bypass, ill need to basically rewire that circuit back to get it to work right... some people need to not do wiring, that diagram really helped!

What is the number on that white wire in your hand?

Ty Yall, I bought a stalk for it, should be here soon, just in case. The wire is tb1 21, also I made a video of the wiring bypass someone did....


https://youtu.be/KT19VxSMAHA?si=PbnbTAgn40NoJ8Yt

Ty for any and all help!

Ok thats a mess… Like many .mil systems, this one is a little complex to meet a spec. It can accept light inputs from a towing vehicle, it can provide service or blackout lighting, it can feed a towing vehicle and operate it’s lights remotely and it can provide 24V trailer output to a commercial semi trailer. 460B and 461B are your right and left rear composite brake/TS lights respectively. K30 and K31 are the relays that feed 24V(use 12v to switch 24v) to the rear 10 pin commercial trailer plug. TB1-27 feeds the section of the terminal board that feeds the brakes. TB1 is a segmented board where each terminal in a segment is connected to every other terminal in that segment(a series of multi pin splitters). These mods on y0urs almost look like someone decided to separate and bypass a bunch of the relays as their main function is to control wether you are displaying visible service or IR blackout lighting… Look up in the top right corner of any page on this forum and you will see the message/letter Icon. I will send you a message…

Hiya ty so much, yes it does look like that as well.. all light turn on with the serv selector, except front blinkers, but no lights blink with turn signal, nor the horn or the windows wipers