My buddy has a 79 SA, every week the battery dies.

He has a new battery and alternator as of june.

We are going to start tearing through his electrical system soon, to see if we can find a sort, of see if something is permanently turned on.

ANy tips or advice?

peace

Geoff

 

Good Luck! thats my tip! heheh

Make sure you have a voltmeter to test the connections... sounds like a goose hunt to me though!

Again good luck! Think your on the right path!

 

Something is draining the battery. Does he have a security system? sound system? good luck, electrical problems blow.

 

power regulator?

 

Are you positive the new alternator is any good?

 

like your avatar gatorgunner.

 

I would think alternator. Maybe you don't have the alternator connected right. Does the 79 SA come with the voltmeter in the dash?

 

The tach doubles as a voltmeter when you turn the key halfway (acc.) on the SA's

 

instead of tearing the whole car apart. find the short the correct way. Charge the battery,next either make sure the doors are closed, or use something to keep the door switches pushed in if the door is open so you don't get a false reading, then disconect the negative terminal. now connect one end of a test light to the battery negative and the other end to the negative cable. this will cause any current flow to be forced through the test light, If the light lights up you have a short, if the ligt does not light up or is very dim then you do not have a short in the system. if you do have a short, here's the easy way to find it. leave the light hooked up as stated above. then start pulling fuses 1 by 1 untill the light goes out, then you will atleast know which circuit it causing the short. If all fuses still leave the light on, try disconnecting all the wires from the alternator/regulator. I've seen too many diodes go bad in the regulator causing the alternator to suck juice rather than produce it!
Hope this helps make your task easier

 

i had a 79, and had the same problem. i decided to sell that car, but i wanted to keep the motor and all that i had in it, so i bought an 81, swaped the motor with everything attached (including the alt), and gave the car to a freind to build in trade for some parts- turns out the voltmeter/tach combo had shorted internally and it was draining the battery.

we found this out by trying to disconnect the tach lead from the coils to trick the voltmeter function to keep working- once we did that with the motor off and the key out of the ignition, the needle would point to 11v's. since it shouldn't read anything with the car switched off, we disconnected the voltmeter and hooked up an aftermarket one- problem solved, the tach just retained the rpm function, and it didn't drain the battery all the time when the key was switched off.

took us alot of alcohol and thinking to figure that one out

 

If you're sure that the alternator is OK (load tested), then here is a cheap and easy fix that also doubles as an anti-theft deterent:

Put a battery quick disconnect on the post. Whenever you park the car, open the hood and disconnect the battery (its usually something like a 1/2 turn). There is then no way that the battery will be drained. Probably a 5 dollar solution.

 

How does that work? You wouldn't be able to read voltage drops across various sections of the electrical system, only the total voltage drop across the entire electrical system. Correct?

 

correct, its not for diagnosis, its just the factory voltmeter

 

thanks jeremy

 

What you would WANT to hook up, to check for the alternator working correctly is an AMMETER...

Jeff

 

What's an Ammeter?

Do you mean Ohm Meter?

 

Ammeter.... Amperage Meter, measures the charging capacity... how much electricity is flowing, not just the strength at which it flows...

Volts = Strength
Amps = Speed

I think that's the analogy my shop teacher used...

Jeff


Edit: found a good site explaining the usefulness of an Ammeter when diagnosing the alternator.

http://autorepair.about.com/library/.../aa122700b.htm