Dash Wiring

[Big_Blue_95gmt400]

My 95gmt400 lost power to more than half the dash (speedo, volt, fuel) everything but the rpm. Now a week later with the key in the run position, the truck
acts as if I do not have the key in the ignition. (Siren for the headlights left on) A
shop made the truck run outside of of the pcm due to a performance kit for the fuel and intake. Radio and interior lights work with the key as well. I’ve checked all of my grounds and upgraded the ground strap from frame to firewall. Is my pcm dead? Or am I overlooking something?

 

[Nickpisp]

Sounds like there’s no power to the pcm.

 

[MIHELA]

Maybe the ignition switch is faulty? You need to start checking for voltage.

 

[Supercharged111]

What is this "performance kit" you speak of?

 

[Big_Blue_95gmt400]

Update:

The performance system is a Fi-Tech 450 system. it has its own computer to run the engine side and the transmission is run by a separate TCU. I've removed the gauge cluster tracing wires and the door ajar siren chimes when the key is in the run/on position but as soon as I plug the cluster back in the chime quits. before the breakdown, the chime would run about 5 seconds when the key was turned to the run position before the start-up. The ignition switch is not faulty because it is still used to start and run the truck on the Fi-tech system.

Only the RPM gauge and oil pressure work with the high beams, turn signals, and seatbelt lights working. nothing else will move or turn on.

I have cleaned the ground inside the cab left f the I/P and the ones inside the engine bay; top right cylinder head on the firewall to the back of the intake manifold, left firewall to frame, frame to the negative battery terminal, and the front intake manifold to negative battery terminal. where are the other grounds inside the cab?

 

[Supercharged111]

Since the fitech, was there a time when everything worked?

 

[Big_Blue_95gmt400]

Since the fitech, was there a time when everything worked?

The system has been in the truck since I bought it 2 years ago and probably a year or 2 before that.

 

[Supercharged111]

I'm guessing all this worked 2 years ago when you bought the truck then. First thing I'd look at is the wiring handiwork that the shop performed. Next I'd be looking to the schematics. Do you have access to schematics?

 

[Big_Blue_95gmt400]

I have all the schematics. The shop made the truck run After the issue arose where the cluster lost power. The shop gave me a run-down on what they did and how they were able to get the truck to run.

Since my last post, I have redone all of my engine bay grounds, cleaned all the fuses, and checked for power on every wire. I have power for everything going into my dash cluster but as soon as I plug in my cluster, the dash acts as if there is no power. I am beginning to think there is a short with the cluster.

I have printed out from "PRODEMAND" Ground Distribution Circuits, the Power Distribution Circuits, and the Engine Performance Circuits. I've traced the wires on paper and in the truck and I cannot find a loss of power.

I guess, would a bad cluster cause the truck to lose power to the PCM?

 

[Supercharged111]

I don't see how, but then again I'm not staring at the schematic. Have you verified with a meter that the PCM is losing power?