I just bought a 98 F150 supercab (5.4L/auto/4wd)from auction and I notice when I hit the brakes the interior light comes on (dim). Any ideas where to look? Also the pass side window won't go down (either side switch tried & doesn't work, also checked fuses-ok), are the motors prone to go bad on these trucks? I have some other stuff to bring up but that will be at a later time. Thanks in advance.

 

The first issue is probably a bad ground circuit.

Pull both side kick panels and inspect the ground lugs and wiring connections that provide the various ground connections to the cab's body. You'll probably find one that has rotted away.

 

Thanks for your response, I'll keep you posted on the results. I noticed it seem to change the lighting problem else where, now when I turn on the cargo/interoir light, it lights up the third brake light and not the cargo lights. After I check the kick panels, I may pull the headliner and make sure the wiring has been messed with. I have a feeling I bought a nightmare!

 

Or, your windshield may be leaking and getting the GEM module wet.
Rich

 

I agree with projectSHO89, grounds missing will cause all kinds of weird things especially when lighting is concerned. I have heard of other guys with rust problems in the foot wells too. Good luck!