Ok fellas quick post here 68 Grand Prix New alternator New battery Completely dead in about 2 weeks No lights are left on Any thoughts before I start looking around All factory type stuff nothing fancy What else can cause a draw on these non ac car 400 motor Maybe new alt is bad Will inspect Saturday morning For now she's on a slow charger
External voltage regulator? I’ve had them fail and do that, but I also know some ‘68 Pontiacs are internally regulated. If it’s internally regulated, I’d vote for the alternator. Beautiful car by the way; my son’s ‘project’ is a double black, no vinyl top 400 car on eight lugs… Patrick
A bad diode in an alternator will slowly suck the juice out of a battery. It will also still charge it. Had that problem once
Sweet ride Patrick I've always wanted one for years finally got this one owner ride Love the 8 lugs wheels too Those are bad A S S
Wow, 2 cool cars! Joe’s is most definitely beautiful! That’ll give you something for your son to work towards Patrick.
I would check some simple things first, like make sure your trunk, glove box, and under dash lights go off when the doors close. I see you have some after market gauges and 8 track player that I'd check. Are the hideaway headlights vacuum or motor driven? I had a parasitic draw on a tape player where the drive was on without a tape in. Possibly an open circuit or stuck relay. You can check with a multimeter, red on negative cable end disconnected and black on negative battery terminal. Make sure everything is off and fully charged battery. At least you could eliminate that possibility.
Clock Disconnect the clock power wire, and see if it make a difference. The "points rewind" mechanism after several years became a problem in most of these cars. The points "stick" and create a small draw that can drain a battery in several days or a week or so. Other things are bad grounds, resulting in ground loops and brake lights or other circuits being "included" in the "alternative" ground paths created through other circuits and accessories when the primary ground paths are compromised. (path of least resistance). If you do not know how to isolate and trouble shoot wiring/ground issues, say so. Many good people can help you sort it out. Can drive one nuts trying to figure out what is drawing current from the battery, when system is "off", and worse, is a wire fire with your car in a garage, when you are asleep. I have seen several of these things happen over the years. Trust me. You do not want to have that experience.
You can hook a small lamp up between the battery and it’s positive cable. See if lights up with everything off. If so, pull fuses till the lamp goes off. That will point you in the direction of the short.
Best advice in this thread. Test, don't guess Once you figure out which fuse turns off the test light, look in the service manual and find out what gets power from that fuse. Then you can narrow it down even further.
Ten four guys Yeah no lights are on for sure 8 track not connected yet Only water guage hooked up for testing purposes for now No external regulator it's internal I need to see if the person behind the counter gave me the correct alternator to begin with. Thanks
The test light is ok but running the multimeter is better. Put in amps and hook it up the same way. You'll get quantifiable results instead of a light bulb getting maybe dimmer.. Note- pull the dome light fuse first. Otherwise you might pop the fuse in the meter or the bulb in the test light. Either way it'll screw with your tests.
On alot my old cars I just always disconnect battery if going to sleep for more than a week. However my 72 SunCoupe can sit for 6 months and start right up with it connected the whole time. But my Roadmasters with kill battery in a month.....
First off, you need to see whether your charging system is working or not. If it is, then concentrate on a draw. A simple volt meter on battery post while the engine running is a crude charging system test. On a fully charged battery, the voltage should be 13.5v+. Unless you have pile and an amp clamp, running voltage is only giving you half of the picture. But if you're hanging around <13v while the engine is running, you have to do some charging system testing.
Ok so I need an alternator with the old school plug in the rear with internal voltage regulator Guy at parts store has no clue So now the online search starts I can go with a one wire but want to leave this car somewhat stock I guess. I use O'Reilly's usually
