sixtysix

Car died out while driving-jumped it to get home......I recharged the battery-its reading 13.82or so...
How do I know if I need a new regulator or alternator?
I am trying to avoid taking the alternator off and having it tested at a store.

If I get a reading off the battery when it is running and then get a reading by BY passing the voltage regulator the by pass reading should be higher or lower and what will this be telling me?
If the by pass reading is higher the voltage regulator is good ?

How should I figure out what is wrong...both regulator and alternatorare about 2 years old.
Thanks scott

Its a 1966 V8

blazerdup

One easy trick is to have the car running and disconnect the negative battery terminal, if it dies its your alternator. Other than that, I couln't tell you if the regulator is bad.

jlg2002

While that is a quick soultion, it's not the safest way to do it. The best/safest way to check if the alternator is working, is while monitoring the battery voltage, jumpering the regulator plug's A to F terminals. If the alternator is good the voltage should jump way up and the alternator should whine. if no voltage increase or whine, the alternator is bad. If the voltage is increased- its in the V Reg or it's grounding.

sixtysix

what are the A and F terminals on the regulator?
thanks scott

musnicki

Check your belt also. It can be loose or dry rotted which won't turn your Alternator as well as it should.

James

kalli

JLG: i have to try that at some stage (or at least check on the diagrams what this test is doing). sounds interesting.


sixtysix: the voltage regulator is bolted inside the engine bay. it has 4 terminals and if you look closely every one of them is labelled with a single letter

tx65coupe

I have always heard guys talk about disconnecting the negative battery terminal to test the alternator, but have never done that myself. I would try what JLG suggested.

Good point Musnicki.

I believe that Kalli is right about the labels.