65 with bad alternator

My 65 impala keeps draining the battery. At first though it was the alternator. Replaced alternator and problem continues. The generator light is on when you crank the car and after awhile it drains the battery. What's the problem. What should i check next. Oh, i also swapped batteries.

Sounds like somethings shorted out.

Was the replacement alternator NEW?
Was the battery swapped out with a new one?

If NOT, used alternators/batteries are not worth the time and effort.

Also check the starter wiring , make sure all your connections are clean and tight.
Also check the grounds on the engine/firewall.

I know this car originaly had the Generator,
did you do the conversion,
or was it already done when you got the car?

assuming the Altenator was retrofitted correctly try this: if its fast drain on the battery check all your main power wires under the hood especially the starter wire 'cause it usually is routed incorrectly (after the starter has been serviced) near the exhaust manifolds and/or frame and can rub through. If its a slow drain it'll be a bit more difficult to track down. you can start by disconnecting a fuse to one system such as the interior lights and see if the battery continues to drain. If so, replace that fuse and pull another. This will only tell you which system has the short next you will still have to track down the offending wire in the affected harness.

your car originally came with an externally regulated alternator. If it is still there, it could be the problem. The OEM regulators were mechanical contact point style, and they can stick closed and drian the battery when the ignition is off. The replacements are all electronic (although externally they look the same) to rectify this problem. Many people bypass the external regulators and rewire the car to accept an internally regulated alternator. If your car has been modified for the newer internal regulator, then disregard the above suggestion, as it couldn't be the problem. Another part that can cause the battery to drain over time is the horn relay. It is mounted under the hood near the drivers side headlamp, and can corrode internally causing a draw on the battery.

Rich, you talking about something like this?
http://i28.photobucket.com/albums/c242/xeroinfinity/11X17RW24/66oldsReg.jpg

You sure, that looks like the horn relay on a 65-66 Impala, just did a restoration on one, BTW I have wiring diagram for that car if anyone needs one.

Hey Max,
its the starter/horn relay and part of the charging system on my 66 olds. All the altr. wires go to it and the battery. The green/blu wires(on the right) goto the horns.

Pretty Prehistoric :lol:

Thought so, the Impala has a seperate regulator, you'd think they would be the same, mine was a 65 SS Conv. sold for 26K

I wasnt certain on which GMs had the seperate regulator.
But after I thought about it, my alternator has the regulator biult in. :banghead:

Nice price you got for that 65' Impala :grinyes:
Being a conv probly helped :D

Thanks guys for all the info. Been busy lately but hopefully can try the suggesdtions tomorrow.

OK, I've checked all the fuses and nothing is pulling from the battery. The battery does not run down overnight, or even a few days. Only when your driving or just letting the car run.

All GM vehicles prior to 1971 had the external regulator. 1972 was the changeover year, and all 1973 and newer have the internal regulators. the easiest way to tell them apart is look at the plug. the internal regulator alternators have the spades like this (--) and the external like this (II)

It was the regulator. With myself being unexperienced with auto repair, i thought that box had something to do with the headlights. Thanks for all the help.

Ok guys i know your probably tired of me, but now i have no choice but to get the car fixed because i have totaled my daily driver camaro. After replacing alternator and regulator i continue to have same problem when car running. If i remove the ground wire for the regulator the ligt goes off but i know it's not hooked up right. I've tried tracing down any loose or broken wires with nothing being found. I'm completely lost now and have no clue what to try now.

Have you checked voltage to determine that the battery is draining? Sometimes the charging light malfunctions and comes on when everything is fine, especially at idle. System voltage should be 13.8-15.4 volts with the car running at about 1000 rpm. If voltage is fine, you may want to check the connections for the charge light for corrosion.