Hi all, I've been following this website for some time and have learned quite a bit from previous posts. Now, I have a question maybe some of you can help me with. For the past couple of months my fuse controlling the PCM is blowing It has happened 4 times and seems to occur when the truck is changing gears. I brought it to the dealer but they appear to be clueless on why it's happening. Any ideas ? The fuse is in the power distribution box located under the hood. It's position is # 24

'98 Scab 4.6l
Modifications include Superchip, airraid.

 

Does the trucks engine stall when the fuse blows out? Are you using the right amp fuse.

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1998 F150 Triton 5.4L (4x2)
K&N Air Filter
Pioneer 4100 W/remote
2\10" Rockford Fosgate Punch XLC 2410
CatBack system with Magnaflow system 3" Pipe
3" Performance Acc. Body lift, with lift lips

[This message has been edited by Nacho (edited 02-26-2001).]

 

HI Nacho, and yes, the truck does stall when the fuse blows. At first I thought it was the fuel pump relay because it would cranck but not start. After checking into it I found it was the PCM fuse. Each time I replace it I also make sure to use one with the same amperage.

 

I had the same problem with my fuse in my 4.2 V-6. Had to have it towed twice the first time it spent a week at the dealership under warranty and they could not find anything it would not blow so they gave it back said nothing was wrong. Well a week later it did the same thing and it was towed again. This time it was there for 2 weekss and they finally found the problem . It was a wire to the PCM that ran too close to the exahust and it would over heat and blow the fuse. I believe there was a recall or TSB shotly there after stating that if the fuse didn't blow soon enough the truck would burn up so get it seen about soon.

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98 F-150XL 4x4
black over silver
4.2L V-6

 

RayCee,

This fuse sends power through the PCM relay to the torque converter clutch solenoid, electronic pressure control solenoids and shift solenoids. Have the dealer probe these as your problem seems to only occure when the truck shifts. One of them may be shorting out and blowing the fuse. How often does it occure and at what speed and is the engine warm or cold?

Regards

Jean Marc Chartier

 

Hi Guys and thanks for the info. The truck has been at the dealer for close to a week and they still have no clue on the cause. I'll be sure to bring up the ideas posted here. It's getting kind of frustating that they have the truck this long and can't find the problem. As far as your questions JMC, it happens approx. once a week, and always when the truck is warm. As far as speeds go, it's happened when I was going 70mph to when I was stopped shifting into reverse. Thanks and any more input would be appreciated !!

 

Hey Guys,
I'd like to thank all those that gave me some input into my blowing fuse problem. You all turned out to be correct in your diagnosis, in fact Ditchdoc, it turned out to be the same problem you occured. The dealer found a chared wire on the harness that leads to the trans. He spliced in a new piece and wire tied it away from the exhaust.
My wife found it amazing that the people on this website appear to know more about their trucks than the dealer does.
Thanks again for helping me to get back on the road !!

[This message has been edited by RayCee (edited 03-02-2001).]

[This message has been edited by RayCee (edited 03-02-2001).]