1990 R2500 Electrical Problems

[Shane Mane]

After getting gas I take off from the light and my Sub cuts off on me. I figured it was the Fuel Pump but later find out it's the Relay which blew the ECMB fuse so I unplug the relay, replace the fuse and plug it back in.

Everything is fine until this morning where I get out of my driveway and cut the heat on and it completely cuts off on me again. I check the fuses and none of them blew, the gas, oil pressure and temp gauges are stuck where they were when it was running and when I turn the key, nothing comes on or works. Obviously something electrical but what!? What would cause it to do this with no fuses blown, decent battery and just cutting the heat on? Wires shorting out somewhere? Another relay gone bad? I'm to the point of selling it and putting my '83 Sierra back on the road..

 

[BLOCKHEAD454]

I had a very similar problem once, like you said, when you turned on the heat, it died.
When I turned on my headlights, my motor died. Funny right.

Well I found the headlight swith to be faulty but had to replace the BIG BUSS fuse under the hood to get back on the road. It is located above and a little to the left of the brake booster on a small black plastic plate that it the positive block, or hot block for the ignition. Replaced that fuse and wala, she fired right back up.

Im willing to bet that fuse is blown and before you replace it find what item was faulty in the first place or it will blow again. I hope this helps you.