I've got a 97 4.7L 4x2 scab that I'm trying to diagnose a problem that's causing fuse #13 to blow when the brake pedal is pressed. Some of the diagnostic tests state to scan or disconnect certain components, including the items discussed below:

1. If a truck was not equipped with keyless entry will it still have a remote anti-theft personality (RAP) module? I cannot find a RAP module behind the left side of the dash, where it's supposed to be.

2. The truck has RABS, not 4-wheel ABS. Does RABS have any smarts to provide ABS codes? My scanner cannot communicate with the truck's ABS system, and I'm thinking that's because only the 4-wheel ABS module can detect and record faults.

Thanks.

 

Check the brake light switch under the dash on the column area. It could be bad itself, or the wiring can break right there and cause the system to blow fuses by the two wires shorting together. Just a place to start, good luck.

 

Thanks, doggie. Brake switch is good. RE: fuse blowing, I disconnected the GEM, shift lock actuator, RABS, PCM, and cruise control servo. Didn't disconnect the RAP module because I couldn't find it. Fuse still blows. Time to check wiring, I guess.

 

Since you have a 97 and it's an XL (I think I read), then if it doesn't have power door locks, then it won't have the RAP either. 97-98 are the first years and much is different than 99 and up models.

 

If the keyless entry box isn't there then you don't have it, nor will the wire harness be there....

The abs sensor in the rear diff can throw a abs code if it's bad.

I think those were your questions?

Fuse blowing sounds like a short, I'd get on the back and look under the dash as you play with the brake pedal. Something could be hitting it causing a short, or loose wire

 

Thanks for your responses, guys.