after leaving my buddies house last sunday afternoon, i pulled into the store's parking lot to run in an grab some stuff. as i pulled along side the fence to park, my girlfreind says she smells smoke, and saw a puff of it in the cab. i didnt see or smell anything, but i shut the truck off an got out. smoke started puring from under the hood, so i quickly opened the hood and saw smoke coming from my BHAF. as i looked closer, i could see a wiring harness was on fire, and was buring good enough to catch my air filter on fire. luckily, since my truck was formerly owned by the town highway dept, there was a fire extinguiser behind the seat i never took out. i grabbed it and unloaded it on the fire, but it kept burning. i took my work coat and dunked it in a plastic bin full of rainwater that was riding around in the bed, and pushed it on top of the flaming wiring harness. i then disconnected my negative side of the battery. luckily the fire soon went out, before causing anything super horrible.

i thought the wiring that caught on fire was my trailer wiring that originates in a 7-wire junction box mounted on top of my BHAF. to my surprise, it was not my wiring, but the factory wiring. the 4ga wire out of the alternator that runs though the single pin connector and then up behind the washer fluid tank was burnt through, then it also caused the bundle of wires that that 4ga runs into to catch fire with it. some of those wires go into a 6pin connector, (though only 4 are used) that runs to the alternator, and then back into the bundle, around the washer tank, and up around the firewall. i also burnt the 6 or 8 wires that run down the front fender and run the headlight and blinker on the pass side.

so today i cut out all the burnt wire, probably 10 or 12 smaller wires (blk, blk/yel, tan, red/org, grn/red, so on) and the larger 4ga feed wire. i basically installed new wire inbetween the the good ends of the wire where i had cut out the bad wire. it was pretty much an exercize in matching wire colors.

Now the truck runs and everything works, but according to my guage, the battery is not charging. i have an aftermarket volt meter, not the factory dummy guage. Is there a circuit breaker somehwere, or a fuse for the charging system? diagnosing electrical problems is not my strong suit, so any advice is appreciated.

 

If it were me, I'd take the alternator off and have it bench tested. That fire may have caused or been caused by a short that toasted the alternator (diode trio or other). If it tests good, then look for another issue.

 

Check your intake air preheaters, make sure that a relay didn't stick causing a preheater to stay energized all the time. That could theoretically overheat the alternator and its wiring. It could also drop the voltage, making it look like the alternator isn't charging.

 

my grid heaters do not work, i removed the relays a long time ago