1991 Gmc K1500 Blows Ecm Fuse

dbrianson · January 1, 2010

I have a 1991 Gmc sierra k1500 that constantly blows the ecm fuse sometimes as soon as i turn on the key, i pulled the fuel pump relay and its still blows. I changed the ecm module and it still blows, unhooked the oil pressure switch and it still blows. If i let it sit for awhile and plug in a new fuse it will crank and run for a long time, but if i start down the road it blows the fuse and dies, sometimes quickly and sometimes i can drive a few miles. i have looked over obvious wire and dont see anything but im about to set this thing on fire.

Nytemare · January 1, 2010

I would grab a wiring diagram and see where that wire ties in with everything. Sounds like you have a short in the crank position...look for a wire that goes to that fuse and in turn to the ECM that's hot only in the crank position.

dbrianson · January 2, 2010

I would grab a wiring diagram and see where that wire ties in with everything. Sounds like you have a short in the crank position...look for a wire that goes to that fuse and in turn to the ECM that's hot only in the crank position.

thanks, ill try to trace that out.

dbrianson · January 2, 2010

where can i find a wiring diagram? i've looked everywhere.

dbrianson · January 2, 2010

i forgot to add that the guy who had the truck before me said the ecm fuse started blowing after he changed the starter.

Nytemare · January 2, 2010

Check the starter enable wire for fraying...I believe its still purple on your truck. Its Obviously on the "crank" side of the circuit. Buy a Haynes manual and they will have the diagrams in the back.

Also check that its the right starter and solenoid for this truck. I have seen people remove the solenoid from an older or newer model starter and Frankenstein a starter together to make it work. I would be looking all around that general area.

dbrianson · January 2, 2010

Check the starter enable wire for fraying...I believe its still purple on your truck. Its Obviously on the "crank" side of the circuit. Buy a Haynes manual and they will have the diagrams in the back.

Also check that its the right starter and solenoid for this truck. I have seen people remove the solenoid from an older or newer model starter and Frankenstein a starter together to make it work. I would be looking all around that general area.

Thanks, ill do that.