I have a 1997 Ford F-150 with 132,000 miles, 4.2L 6 cylinder engine. My truck keeps blowing the PCM fuse when I engage the ignition. The relay is fine. It used to finally turn over after changing the fuse 4 times, but now it will not turn over at all. I also have a check engine light that says the upstream O2 sensor is bad. I have no idea where to even begin with this problem. Any advice would be greatly appreciated.
HELLO! Need more info cap'n. What fuse # are you replacing and is it in the eng. Comp? When you say " engage the ignition" is that from OFF to RUN or RUN to START? Does your anti-theft light blink rapidly when it fails to start? Why do you think the PCM relay is fine? Do you have an aftermarket anti-theft or remote start system installed. Is this a man. Or auto trans? Your full and complete answers are needed to accurately diag. Your concern.
The fuse number is 24, and it is in the engine compartment. I believe the PCM relay is good because it does not look blown/bad. What I mean by engage the engine is from run to start. I have no anti-theft (factory or aftermarket) The truck is an automatic
May, 10, 2007 AT 10:23 PM
I tested f24, f30, and the MAF red wire. All three have power with the ignition in the on position.