I have a weird issue going on. The truck just started randomly overcharging. The volmeter will go almost to 18v and fluctuate between that and 14v while the gen light stays on. Once it just fixed itself and started working right again while I was driving. Today it stayed in an overcharge condition and I got concerned and pulled over. I let the truck sit for awhile and when I started it back up it worked fine again. What's going on here? Is the regulator internal to the alternator?
Well crap... Didn't realize the pcm controls the charging rate. That's a stupid setup IMO. I saw the setup for the Ford voltage regulator, I may be doing that. After some thought, I realized I washed the truck right before this all started to happen. I wonder if I somehow got some water in the connectors to the PCM and that's making it act weird. I sprayed the connectors with some WD-40, I guess we'll see what happens. Does it make any sense that it's an intermittent problem? Seems to me that once the computer went bad it wouldn't fix itself.
I know for sure that one time it was overcharging, then went right back to normal while I was still driving. Another time, it was overcharging and I shut the truck off. When I restarted it, it worked normally.
The PCM will reset when the engine is shut off. Make sure all the wire connectors are dry and the battery posts and clamps are clean. Take the top off the PDC box and make sure there isn't any water in the fuse holders.
Old Offroading trick, Dielectric grease is your best friend. If you are power washing the motor I would look at putting some in every connector you can. I find with enough water even the weather pack seal connections will get water in them on the Frog, so I do everything.
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