I bought a used 01 f250 with the 7.3 and it's as usual a wireing nightmare. Anyway on to the question. I have dash lights lights that flicker like a burning man rave, none of the map lights (the ones you have to flip the switch to turn activate on the headliner work, power mirrors dont work and water in the dash mounted glove box. Now I'm pretty ignorant when it comes to water and electronics could these thing be connected, did the water getting in damage the PCM, where would the most common leak around that area be and what can I do to fix this. I've checked fuses and non are blow both in cab and in the engine compt. I plan on doing a cab swap down the road (because rust belt) but in the meantime I'd like to better understand everything. Radio, all gauges, ac/heat, windows, locks, most of my speakers, headlights, cab lights, all work.
NOTE: when I installed new PW mirrors I was checking the fuse/wireing trying the get them to work, fuse was in good shape however still no power jumped the wire from mirror control to fuse and the map lights (I previously mentioned) turned on in accordance to the pos I had the mirror switch in lol.

 

If your windshield or over cab lites are leaking, there is the possibility of moisture affecting the gem located behind the in cab fuse box.

 

What would be the best recorse for that? Seal up both locations and find a new gem? Do you know of any repair sites

 

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It has been my experience on my old e99 that if you have water intrusion it will affect the fuse box. Even though the GEM camps out on top of the FB, mine had absolutely no water infiltration evidence. As the fuse box sits, the back side of it is the low point. Corrosion forms inside the FB, causing bridging between the layers of bus bars inside, which leads to the most random things you can think of. Ex: on a night of warming temps in northern Maine (below 0 for many days prior), my horn started sounding off randomly. And my marker lights in the door started working. Among other things.

My belief is it doesn't take a river of water to lead to these probs, but small amounts over a long time are enough to march you down this path. If you have corrosion built up inside the FB, I am guessing that a drop or two of moisture is enough to wick it's way around and trigger all sorts of good stuff - until it dries up. Thus the random nature of things.

Before one starts throwing the credit card around, it would be best to see if you really need a GEM. Those are getting harder to find. There are/were more used fuse boxes kicking around.