Bad Voltage Regulator?

[1970Moparmann]

Guys, I've always seen a bad voltage regulator provide too much power - can a bad one also provide low power?   My battery is only showing 11.5 when the car is running.  New alternator / all connections are good.

Thanks.

[Pete in NH]

Hi,

Yes, it could be a bad regulator. It could also be a wiring issue or alternator. Just because the alternator is new doesn't mean it's okay.

Post back what you are working on and if it's the stock alternator and regulator and then some troubleshooting might help narrow things down.

[csx4590]

I don't have a voltmeter but my brand new battery died after just 20 minutes with the headlights on. Changed the voltage regulator first before I did anything else and the problem went away...

[1970Moparmann]

Last year was the first year I had no issues with the car and first real year of enjoying the car.   When I bought the car, it had a charging issue and nothing changed until I changed out the old wiring to new.   At this time, I also did some other work and changed out the alternator (stock looking).  All was good until the last few times started the car.   I did have a ground issue with the voltage regulator, so I ran a ground wire from it to a good ground - no change.   I have a new regulator coming in the next few days, so will see if that was/is it.

Thanks.

[1970Moparmann]

I don't have a voltmeter but my brand new battery died after just 20 minutes with the headlights on. Changed the voltage regulator first before I did anything else and the problem went away...

Good to know!  Thanks.

[chargerbr549]

A quick and easy test to do is while the engine is running is to unhook the two pin connector that goes to the voltage regulator and temporarily ground the bottom outside pin the wire is usually green in color, don't ground the top middle pin, the green wire grounded should cause the alternator to charge full bore sometimes up around 16 or more volts depending on rpms so be careful if you rev the engine like this for very long you will start to boil the battery or damage other things, or  another way is to leave the engine off and turn the key to the run position and do the same test with grounding the green wire, if the system is charging properly the front pulley should be magnetized and a wrench or screwdriver should stick to it, if it's not charging nothing will stick to it. Also make sure there is a good connection on that plug to the voltage regulator since I had overcharging situation on my Ramcharger and it ended up being that plug wasn't making a good connection with the voltage regulator, I pinched the terminals in the plug and cleaned the connection and it went back to charging normally.

[1970Moparmann]

A quick and easy test to do is while the engine is running is to unhook the two pin connector that goes to the voltage regulator and temporarily ground the bottom outside pin the wire is usually green in color, don't ground the top middle pin, the green wire grounded should cause the alternator to charge full bore sometimes up around 16 or more volts depending on rpms so be careful if you rev the engine like this for very long you will start to boil the battery or damage other things, or  another way is to leave the engine off and turn the key to the run position and do the same test with grounding the green wire, if the system is charging properly the front pulley should be magnetized and a wrench or screwdriver should stick to it, if it's not charging nothing will stick to it. Also make sure there is a good connection on that plug to the voltage regulator since I had overcharging situation on my Ramcharger and it ended up being that plug wasn't making a good connection with the voltage regulator, I pinched the terminals in the plug and cleaned the connection and it went back to charging normally.

Thanks for writing this up!   Will try this tomorrow.

[1970Moparmann]

Well, I received the new voltage regulator and put it in.  That's all it was.    Thanks guys.

[mopar0166]

Yeah I had my fair share of too much and too little voltage with these external regualtors, then I dropped the doe on a 1 wire alt and no more issues and a very happy battery

[Highbanked Hauler]

   You can get a volt meter for a reasonable price and carry it in the car. There is always a need for one in these cars ..

[rebby]

   You can get a volt meter for a reasonable price and carry it in the car. There is always a need for one in these cars ..

I added one to my trunk and I'm glad that it's there. I also added a spare voltage regulator.

[myk]

Yeah I had my fair share of too much and too little voltage with these external regualtors, then I dropped the doe on a 1 wire alt and no more issues and a very happy battery

Exactly what I did.  The externally regulated dance was too much for me...

[mopar0166]

Id also check and see your amp load,  my alt was too small for what I was running, another reason why I upgraded to a one wire alt.