Are electrical shorts common on '84 trucks? If so, what is a typical cause of a short which causes problems with the charging system. The truck is for sale. The seller has been unable to fix a short. He said that the wiring is stock and has not been modified.

The truck has a 225 with automatic.

The seller told me that he bought the truck and took it on a short drive and within twenty miles had to park it because of these problems. The charging system was unable to keep the battery charged but the alternator checked okay.

I think the truck has the Prospector package. I'd like to buy this truck but would like to be able to fix the wiring quickly.

What about the voltage regulator?

Richard

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Part of Tyrde-Browne Racing

Could be an internal failure in the alternator, could be a failed voltage regulator, could be a failed lean burn computer, could be many things. THe good news is the charging system on that truck is basically the same as the charging system on a 1960 Valiant (OK so the voltage regulator is electric and it is a dual field alternator, but otherwise the same).

I wouldn't let something simple like a charging system short stop you from getting the truck. Play up the problem and bargain for a steep discount.

Could also be a fried fusible link, but then you have to ask what fried the fusible link?
They don't usually go bad without a reason.

Dave

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86 Miser 170,000+
2 1/4" exhaust
Holley 1920 #55
HEI MSD BLaster 2
17.8 mpg

First you have to determine is it a "short" or an "open". A short is an alternate path that bypasses the load and usually will heat up a conductor an open is a break in a conductor and usually will not cause anything to get hot. Your description sounds like an "open" so you need to check continuity between the alt. output stud and the battery + post. if the truck still has the amp gauge it could be open or the connections for it at the bulkhead connector. If that is bad try running a jumper direct from b+ to alt output terminal and see if it charges. otherwise you need to check the regulator (it needs a GOOD ground to work right) and the wiring that goes with it. Hope this helps.

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Dave

1977 d-200 crew cab ex-army pickup wants it's /6 back
1962 Valiant 2 door, 170, three on the tree
1972 d-100 parts truck
80 volare wagon now a parts car

I think I have this right:
1. Pull all the fuses. Remove the ground from the battery. Bridge the ground terminal on the battery to ground with a test light. If it lights, the short is not in any of the fused circuits, but somewhere else. That will be hard to track down.
2. If it does not light, then replace fuses one at a time checking with the light each time. When you put the fuse back in that has a short in the circuit, your test light will light when you go from ground terminal to ground.

Somebody correct me if I am wrong on this, but I think this works. If the test light lights, that means + is getting to ground somewhere and bridging ground to battery ground term with a light will make the current flow from ground through test light to battery ground.

Sam

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For a short that would be a good start on finding it. but I still recommend testing alt output to battery positive as a first test with your symptoms. If you had a short the battery would go dead but the amp gauge would still show charging. You described a "no charge" condition. jm2c

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Dave

1977 d-200 crew cab ex-army pickup wants it's /6 back
1962 Valiant 2 door, 170, three on the tree
1972 d-100 parts truck
80 volare wagon now a parts car

Could be somethign as simple as loose or corroded battery terminals. Or a bad battery. Or...

I appreciate the ideas

As the seller is out of town I haven't yet seen the truck. He said that a door has a dent but the truck is otherwise clean. Whether I get the truck is more about the appearance than the electrical problem. Most older vehicles have some electrical problems - its just the way it is. The seller is a professional mechanic that is knowledgeable about slant sixes. He said he has a '71 Valiant that he modified to run a 15 second quarter mile at the track.

This weekend I'm also looking at a Sweptline truck with a slant six and uteline bed. I prefer the simpler model.

In reading Consumer Reports tonight I see that many of the popular new automobiles are prone to complex electrical problems. I'm not looking forward to working on 2014 cars when these have aged.

I looked at the truck, not too bad looking. Needs paint and a drivers door. He said that someone from Del Rio is coming to pick it up tomorrow. He had most of the wiring loose.