GenerationChevy

Hey all..

1994 Chevy Suburban K1500 with the 5.7l...

My ECM/IGN fuse keeps blowing randomly... And I mean, randomly.

Sometimes, it will blow as soon as you turn the power on to the key, even without getting to the start position.

Sometimes, it will blow driving down the road at various speeds, or at idle.

Sometimes, it won't blow at all for a week at a time, and then when you least expect it, it'll blow.

Sometimes, you have to put 5-10 fuses in over and over until it finally starts. Then sometimes it will keep running, other times it'll run for about 10 seconds.


What I do know...

While it's running and driving down the road, the tachometer and speedometer will jump the second before the fuse pops.


Other than that? It's a mystery.

I thought I had fixed it when I had redone the connections at the battery because once I did that, the truck ran fine for a few days... Then it blew again.

Then I thought I fixed it when I had changed out the ground cable from the negative battery to the sidewall, because it ran fine for a few days... Then it blew again..


I took the battery to check to see if it was fine. And everything checked out.


I'm at a loss. Thankfully, I have the next week off for vacation, so the only other thing I can think it to start tracing wires from the fuse box through the firewall.. Which means breaking up that wiring harness...


Any other ideas before I do all that?

a55bruce

Some ideas for you.
I'd check the pink/black wire for chaffing, or bad wiring at the following items:
Powertrain Control Module (PCM)
Engine Control Module (ECM)
TCC/Stoplamp Switch
Evaporative Canister Purge Solenoid
EGR Electronic Vacuum Regulator Solenoid Valve
Air Switch Solenoid
Knock Sensor Module

Any of these parts, if defective could also be the problem. You could try to unplug some of them to see if the problem stops occurring.
Good Luck, and let us know what you find.

GenerationChevy

Update:

I believe it has something to do with in the steering column. The reason I believe this is because every time I make a right turn, and then turn the wheel back straight, the fuse pops...

It won't do it at idle, but as soon as you put it in drive and go down the road, it doesn't matter how hard or how easy you turn the wheel...

It doesn't pop when you turn right, but when you straighten back out...

Also: I noticed that my high beams do not work anymore... When you pull back on the turn signal switch, the headlight just go out, they do not click and switch to high beams...

Mikeemike

Did you ever find the problem GenerationChevy? I have the same exact problem except I don't have to straighten the wheel back out, it just blows the fuse as soon as I turn right... Please post how you fixed it if you don't mind