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Alt light on HELP!

Dkutz

Dkutz

Member
time to test the knowledge of this board. Here's the deal.

My winter project was to replace the fan and install a shroud, which led to an engine compartment detail. New painted walls, air cleaner valve covers, rad support paint, and general freshening. Got it all back together and the alt light came on.

Checked all connections grounds etc, still on.

Did some tests, pointed to voltage regulator. Replaced that 4 different times. No luck.
Tried a new alternator, no luck.
Tried jumping the reg plug, volts go to 18 at the battery.
Just got a repop autolite reg from NPD, and a new engine ground cable. Nothing...

I am stuck... Ideas?

About ready to give in and take it to the shop...
 
fuses OK ?
cable shortcut ?
ground of voltage reg ok ?
groundstrap engine to firewall ok ?
groundstrap body to engine ok ?
just some ideas.
 
there are not fuses in that circuit.
Checked the continuity in the lines OK
as I said inthe post, new ground strap
 
Have you checked the voltage at the battery with the engine running? If you have 13.5-14 volts, everything may be working right except the light.

If you are not getting the proper voltage, then chase each wire separately and verify they are connected to the right terminals.
 
Check to make sure the alternator and regulator are grounded? With the fresh paint you may not be grounded through the brackets.

Other than that, I'm at a loss.
 
just an update. After three alternators and 5 or 6 VR's the car is fixed. Ended up taking it to a auto electrician saturday. He ran all the tests I did, replaced the VR twice. And then went through the Alternator, which he ended up rebuilding. Still no charge and ALT light on. I mentioned that the ALT light itself or a resistor in that line Might be bad. So he cut the green/red and put in a test light. The ALT charged. ALT light stayed on. So we assumed it was the bulb or resistor. I had to leave so I let him deal with it. Called about an hour later and said he found the problem.

Turns out when I redid the engine bay and put it all back together, I pinched one of the lines in the harness that runs from the VR to the firewall with the bolt that bolts the brake line bracket to the engine bay wall.

So contrary to most suggestions, I had too much ground. Funny thing is I pulled the plug at the firewall to look, and didn't notice the pinched wire
 
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