I just did a second engine swap on a 98 Blazer 4.3 4WD, the previous one was done by someone else.

The fuel and temp gauges do not move from dead bottom, the battery, low fuel and security lights are lit and the PRNDL lights up, but does not have an actual indicator as to what gear the truck is in. The scan tool also does not want to communicate with the vehicle.

We have triple checked all the fuses with a test light on both sides both underhood and in the side of the dash. We have searchrd and searched for a loose ground at the back of the block, dropping the crossmember to move the engine up and down to gain access to the firewall. We have wiggle tested the entire harness, cleaned and reattached all the grounds on the block.

I doubt that the cluster or ignition switch picked this time to die, so what else could we be missing?

 

Spent the day checking voltage drops, resistances and visually inspecting the entire harness for damaged wires. Everything checked out again, so we borrowed a PCM from a friend and TA-DA the cluster works.

I don't know why it picked this time to die, but since I was fixing someone else's mess, maybe they spiked the voltage to the PCM somehow before I got a hold of it, or maybe it was struck by lightning in the parking lot, LOL.

 

I'm having the same problem. I changed the pcm but its still not working. Ideas?
I did change it with a used older model pcm. I don't j ow if that would affect it or not.

 

Any ideas?

 

There is a fuse in the side of the dash for 4WD. If this fuse is blown you will have those issues. Replace the fuse.