Alternator/Charging Issue '69 Coupe
Thread Starter
Instructor
Joined: Jun 2010
Posts: 128
Likes: 0
From: Austin TX
Alternator/Charging Issue '69 Coupe
Good afternoon All,
I've been chasing electrical gremlins for a while in my '69 small block coupe, I know unheard of, right?
After lots of research here, and repairing/cleaning connections I have limited the issue to a lack of charging of the battery from the alternator.
I've done the major component replacements (new alternator, new battery, both of which test fine) but I still am not getting the charging capacity that others say I should have. With a multimeter I get a reading of 12.2 volts at the alternator and 12.2 at the battery with the car running. It is my understanding that for the system to be charging correctly it should be 14.5 volts.
One other issue that has cropped up recently is with my ammeter. It was working fine and recently has gone wonky. It was reading at a high discharge level, which I thought was symptomatic of a bad alternator, but it is still reading the same with the new alternator.
All of the wiring from the alternator goes through the key buzzer/horn relay and I was wondering if this could be the cause of the charging issue? Any insight or input on this issue is greatly appreciated because I'm now stumped as to what could be causing the problem.
Thanks!
Randy
I've been chasing electrical gremlins for a while in my '69 small block coupe, I know unheard of, right?
After lots of research here, and repairing/cleaning connections I have limited the issue to a lack of charging of the battery from the alternator.I've done the major component replacements (new alternator, new battery, both of which test fine) but I still am not getting the charging capacity that others say I should have. With a multimeter I get a reading of 12.2 volts at the alternator and 12.2 at the battery with the car running. It is my understanding that for the system to be charging correctly it should be 14.5 volts.
One other issue that has cropped up recently is with my ammeter. It was working fine and recently has gone wonky. It was reading at a high discharge level, which I thought was symptomatic of a bad alternator, but it is still reading the same with the new alternator.
All of the wiring from the alternator goes through the key buzzer/horn relay and I was wondering if this could be the cause of the charging issue? Any insight or input on this issue is greatly appreciated because I'm now stumped as to what could be causing the problem.
Thanks!
Randy
Melting Slicks
Joined: Aug 2008
Posts: 2,200
Likes: 3
From: Lehigh county Pennsylvania
The 69 model year was the first with an internal voltage regulator.
Horn relay might be your problem; it was for me. My ammeter would, on occasion, show 40 amp charging. Which might be correct after cranking the starter for awhile. But mine would go 'wonky' at other times with only the constant drain of my Carter electric fuel pump. I changed out that relay with one from one of the big box auto parts stores. Cured my problem. I also cleaned my negative battery ground terminal strap-to-frame connection just for good measure. It was one of those 'while I'm at it' situations.
Horn relay might be your problem; it was for me. My ammeter would, on occasion, show 40 amp charging. Which might be correct after cranking the starter for awhile. But mine would go 'wonky' at other times with only the constant drain of my Carter electric fuel pump. I changed out that relay with one from one of the big box auto parts stores. Cured my problem. I also cleaned my negative battery ground terminal strap-to-frame connection just for good measure. It was one of those 'while I'm at it' situations.
Last edited by 69 Chevy; Jun 4, 2012 at 10:48 AM.
