Total System Failure

[marsocho]

Electrical gremlins are rearing their ugly heads again in my 62 D100. Here's the breakdown: it first started with the horn dying -- truck ran fine but the horn wouldn't work while driving (even on the highway); about a week later headlights dimmed a little while driving at night, and then a day later the tail lights died; next day truck wouldn't start. The ammeter was slightly below the mid-point when it died. Had a mechanic rewire the alternator and replace the voltage regulator (the battery is new). When I got it back from the shop, it worked fine for about a week; the ammeter was around the 3/4 positive mark when i drove it home. But within three days, the ammeter was a tick below halfway again. Approximately a week later, the exact symptoms started all over again: first the horn died and then about 10 days later the tail lights went out and then it wouldn't start.



Any ideas on what's causing this? Thanks in advance fellas.

[PDQAUTO]

check for a dead short positive side of battery to ground check the resistance
I went thru the same thing . Took me 2 days of chasing wires til i found the short

[Hobcobble]

Had a mechanic rewire the alternator and replace the voltage regulator (the battery is new).

By "re-wire", what did your mechanic do?
http://www.sweptline.com/tech/62_65wire.jpg
John

[marsocho]

i should have chosen my words more carefully. instead of re-wire, i should have said that he told me he fixed a lose connection in the alternator. thanks.

[Hobcobble]

i should have chosen my words more carefully. instead of re-wire, i should have said that he told me he fixed a lose connection in the alternator. thanks.

Did your mechanic then bench test the alternator to confirm proper output?
John

[marsocho]

that's a good question. i know he did a bench test to determine that it was an alternator issue in the first place, but i'm not sure if he did one after he repaired it. lucky for me, i just remembered the work is under warranty, so i'll take it back to the shop and let you know what i find out.

[wally426ci]

Id get a new alternator and put it in myself.

[digdoug]

Hint...check the voltage going to the voltage regulator.(black wire)

[marsocho]

Hint...check the voltage going to the voltage regulator.(black wire)

bingo. talked to the mechanic and it appears to be an overcharging problem -- the voltage regulator was toast. upgraded the VR to handle higher output, so hopefully that does the trick. thanks all.

[marsocho]

just an update to close the loop: the switch from the mechanical to solid state voltage regulator did the trick.