1996 Dodge Ram 30A fuse blows

MIKE4327

MEMBER
1996 DODGE RAM
V8
2WD
AUTOMATIC
19,000 MILES

When I start the truck (5.9L) it runs for a short time and then the 30A fuse in the PDM blows. I have underfused the wiring going to the ignition coil, the O2 sensors and the fuel injection, but the 30A keeps blowing. When I replace the fuse the engine runs for a while and then blows again. I have had the alternator checked and it's fine. Since it runs, I'm assuming the Automatic Shutoff relay is functioning OK. Is it possible I have a problem in the PDM, or am I looking at replacing the ECU because the voltage regulator is kaput. I didn't have this problem until about two weeks after I installed a JET performance module at the ECU, but I'm not certain if that had anything to do with my problem.

Friday, November 28th, 2008 AT 12:32 PM

1 Reply

BLUELIGHTNIN6

MECHANIC
16,542 POSTS

Hello Mike4327

Thanks for the donation.

Well, a fuse that constantly blows is an indication of one or more possible issues.

1. The fuse is not the required ampage, causing premature fuse failure.

2. There is a short (possible bare wire earthing) in wiring throughout the system which the fuse is used for.

3. There is simply too much electric current running to the fuse.

Normally, when the voltage regulator is faulty it will drain the battery.

See how much current is at the fuse insert with a meter and post your results. I will follow up.

Hope this helps.

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Friday, November 28th, 2008 AT 12:48 PM