Not Charging

[Rick62]

I have an '84 D100 that was originally a lean burn slant six. I converted it to a 440 more than thirty years ago. The motor was recently removed and freshened by a local engine builder. It is not charging. There is no voltage change at the battery when running. I thought I might get lucky and fix it by changing the regulator, no luck. What confuses me is the amp gauge doesn't move. It stays neutral. Turning the headlights on with the engine running or not doesn't move the amp gauge. This symptom makes me think the alternator may not be the problem. The battery was recently replaced. I don't drive the truck much so I don't know when the problem started. Can anyone here suggest where I should look next? Thanks!!

 

[Jeff Peterson]

Sounds like the amp gauge failed.

 

[pnora]

I have an '84 D100 that was originally a lean burn slant six. I converted it to a 440 more than thirty years ago. The motor was recently removed and freshened by a local engine builder. It is not charging. There is no voltage change at the battery when running. I thought I might get lucky and fix it by changing the regulator, no luck. What confuses me is the amp gauge doesn't move. It stays neutral. Turning the headlights on with the engine running or not doesn't move the amp gauge. This symptom makes me think the alternator may not be the problem. The battery was recently replaced. I don't drive the truck much so I don't know when the problem started. Can anyone here suggest where I should look next? Thanks!!

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That's not a true ammeter. Its a shunted style and has very little passing through it. Check the bulkhead for any melted wires. If ok proceed. I would be looking at the alternator or wiring. 1st step unplug the two small wires at the alternator. Check for battery voltage at the stud. If so step 2-Turn the key on and the small little [BLUE] wire should have 12 volts. If so plug it back on. Step 3 with the engine running attach a jumper with a good ground to the other terminal. It should be charging. If not get the alternator tested. If you failed in step 1 or 2 fix the wiring. Its a basic simple system.

 

[Rick62]

That's not a true ammeter. Its a shunted style and has very little passing through it. Check the bulkhead for any melted wires. If ok proceed. I would be looking at the alternator or wiring. 1st step unplug the two small wires at the alternator. Check for battery voltage at the stud. If so step 2-Turn the key on and the small little wire should have 12 volts. If so plug it back on. Step 3 with the engine running attach a jumper with a good ground to the other terminal. It should be charging. If not get the alternator tested. If you failed in step 1 or 2 fix the wiring. Its a basic simple system.

My alternator has two small wires. Same procedure?

 

[pnora]

My alternator has two small wires. Same procedure?

That is what I said. Read it. Remove the two small wires. The big one is still on the battery. Unless you have some different alternator or has been converted to a one wire self regulated. If you do not have 1 big wire and 2 small wires forget what I have said period. I did edit my post on the little wire color.

 

[Rick62]

That is what I said. Read it. Remove the two small wires. The big one is still on the battery. Unless you have some different alternator or has been converted to a one wire self regulated. If you do not have 1 big wire and 2 small wires forget what I have said period. I did edit my post on the little wire color.

Thanks!! I'll give that a try.