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New Alternator and VR, Showing High Voltage Output

My 1969 Plymouth Barracuda’s alternator was no good. I got a new one and installed it. The voltage was reading almost 18 at a high idle, and changed significantly with throttle changes. I replaced the voltage regulator and now the voltage is steady, but it’s sitting at around 15.5 volts, which most sources are saying that’s too high. The battery is good, I had it tested last week. Any suggestions/ideas?

Alternator: 7006A
Voltage Regulator: R280

Why didn’t you take the “new” alternator back for another one? Putting out 18v is way too high. 15.5v is still to high. The max should be around ~14.5.

18V from the new alternator with a broken regulator seems about right. I would say the new regulator has a problem. It can be adjusted for the proper voltage. The cover needs to come off but I am not sure how to make the adjustment.

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You should be able to adjust that regulator. Chrysler didn’t introduce the solid state regulators till around `74 or ~75.

Here’s a link which should help you, as it has some pictures of your regulator opened up.
https://www.autozone.com/repairguides/Chrysler-Full-Size-Trucks-1967-1988-Repair-Guide/ENGINE-ELECTRICAL/Regulator/_/P-0900c15280052989

I remember adjusting regulators of that vintage. It’s very doable and works well. Do make sure to check the voltage again after you replace the regulator cover, as it tends to affect the voltage.

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Thanks! Adjusted it and it’s running great now👍

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