M1079 electrical help please.

Well it seems to be just bad dash relays and circuit breakers. I now have power to the dash and it will turn over good but won’t fire. I’m sure that’s from sitting for 3-4 years.

does the primer work/is it moving fuel?

So the primer was firm. We just jumped the fuel shutoff solenoid and it fired right off. It is not getting power. The “stop” emergency light on the dash cluster stays on. Is there a low coolant switch?
The coolant is super low.

No low coolant switch.. power flows thru CB79(same CB that powers the trans controller), Thru the de-energized contacts(30-87A) of relay K19, the start inhibit relay(allows cranking without starting for maintenance after you push the button in the power panel). From there it’s right on down to the run solenoid… This is one of those places where a 4 pin relay in a 5 pin socket will mess with you. Does K19 have a 5 pin relay in the socket?

Well we got working relays and breakers in all the right holes and it runs.

Now to fix the hydraulic system for the spare and cab.
Is there anything that needs to be engaged in the cab to run the system? Or push the pump button and set the controls to the item you want to move?

The park brake must be set/park air removed in order to get air to the air/hydraulic push button control...

Hi all, I have some more questions. I went and picked it up and drove it to my house to do more and repairs and store it / show it.

The front emergency glad hand leaks air constantly out the bleed hole. What is causing that?

The “stop” light on the cluster stays on sometimes, I’ve read that is the check engine light on civi cars. How do I diagnose why it is on?

How noisy is drive train in these? I thought I felt driveline vibrations and or a grumpy bearing or something sometimes on deceleration.

The CTIS box light stay on constantly lit up. Where do I start with that?

Thanks again everyone!

1. front gladhand leaking is either a bad 2-way check-valve under the drivers floor(top one) or the system charge check valve down in the bumper below the red gladhand. When you apply air to the red gladhand when towing the vehicle, it applies park air to release the towed vehicles park brakes, and it charges the air tanks so the blue service gladhand can remote control the towed brakes along with the towing vehicles brakes.

2. the stop light, lights along with the front air rear air idiot lights. with air tanks drained and engine off, these 3 lights plus low oil pressure and the low air warning horn in the dash should come on when the ign switch is turned on.

3. The drivetrains are pretty noisy, the hub gears add a lot of noise. you need to note the frequency of vibrations to try and determine what is making the vibration. at the overspeeds these trucks run at(DS angle vs RPM is above redline at highway speed), it is absolutely vital that the driveshafts are perfect(balance, slop, indexing). a thrown shaft usually wipes out the transmission/transfer.

4. What CTIS lights are on solid? All 5 on solid = internal BIT failure, and the module is toast... Sadly not an uncommon situation. you can try hitting it with a hammer mine was like this when I got my truck, replaced it with 3 switches and a pressure gauge for manual control...

I have several utube vids on brake, electrical, plumbing, fuel sys and hydraulics. search for username "Rronmar"(3 R's) on Utube to find them...