Minor battery drain

[djnolan]

Does anyone know what might be causing a minor battery drain on an 87S.

Using the Ohm meter method, it reads a little high across the main positive cable to ground, around 60 Ohms. According to Ohms law I=V/R, that is a current draw of around 200 milliamps and it seems to be enough to run down the battery in two weeks or so of not driving..

I checked my 85.5 N/A and it reads 300 Ohms accross all leads combined, or about 50 milliamps.

Question, what is off of the main positive batt lead that could be drawing this much current? From the parts diagrams it looks like the starter solenoid is the only item there. Have the solenoids been known to go bad and pull current back into the starter switch or the alternator or somewhere?

Are the any complete electrical diagrams for these cars? The parts diagram show minimal detail on this aspect and I am trying to avoid getting under it to see where the main lead goes.

Any advice would be appreciated.

[Turbo_ZA]

200 milliamps is far from minor, it shouldn't exceed 60mA.
ftp://arakis.gotdns.com/Downloads/944%20Electrical%20Manuals.rar

[John_AZ]

The normal resting current is about 10ma

This is my 1987 924S with a cheap Harbor Freight multimeter. 8.65ma.



Start the meter at 10A and move the dial down to avoid burning out your meter.

With the meter in series with the positive cable and the positive battery post, start removing one fuse at a time to see which one will drop the amp draw.

Usual culprits are door light switches, glove box light switch, emergency brake handle switch, and the BIG one-----short in your radio/CD/video whatever. Mine was in the radio.

GL
John_AZ
1988 924S + 1987 924S

[djnolan]

I checked each of the positive leads at the battery separately. The main positive cable is the one that is drawing all of the current. The smaller leads when separated have small draw so that would seem to rule out the radio and lights.

The main positive lead goes to the starter and solenoid. Does it also go to the alternator?

[djnolan]

Folks,
The link above is to an 88MB document with a dot RAR extension. I found the same document at http://www.cannell.co.uk/Manuals.htm

It answers my question about the starter and alternator wiring so many thanks! I will have to do some more trouble shooting to figure out where the current drain is cominfg from.

[djnolan]

[bearone2]

bad door switch/s, central locking, cig lighter/clock, aftermarket alarms can be significant draws.

check for corrosion on all batt cables.