240 Battery Drain Issues

bfrancese · Post by **bfrancese** » 11 Dec 2012, 10:28

Hello all

First, thanks for all the help everywhere. Long story here so here's the skinny.

Car: 1990 240 DL Wagon
Issues: Sudden battery drain

Ditched my 94' 850 after some head gasket issues + picked up a 1990 DL for crazy cheap. But I've had electrical gremlins ever since. First issue: quick drain with lights dimming + blinkers causing car to die suddenly when stopped. Resolution: replace voltage regulator. Seemed OK. Second issue: Weeks went by, but suddenly the same issues began happening again. Resolution: took out battery + alternator. Bad battery, but good alternator + bad belt tension. Replaced battery + belt. Third issue: weeks went by again. No issues then suddenly on rolling windows down I began losing power once again, but not as bad as before. Left over night + she barely cranked back up, but got into a garage to do some wire tracing. This is where I am.

Seems fuse circuit number 8 which controls power locks, clock, interior lamps is the culprit. I disengaged it, charged it up + this morning it started, but very slowly.

Now I'm stuck. Not sure, but there seems to be a parasitic battery drain, but I've disengaged the wire where there seems to be a problem, but getting low power when idle + slight needle jump on the speedometer when idle.

Any suggestions?

Post by **billofdurham** » 11 Dec 2012, 11:41

Fuse 8 covers central locking, interior and glove compartment lights, luggage and engine
compartment lights, radio, power antenna and clock. Have you checked that the engine compartment light goes out when the lid is closed? It is a common fault on the older cars.

Bill.

bfrancese · Post by **bfrancese** » 11 Dec 2012, 12:14

Bill

I did check it. Did notice though that the wires running to the trunk hatch are frayed. Though I don't open it much I wonder if it's enough to cause a short.

Post by **billofdurham** » 11 Dec 2012, 12:28

That is a common fault on the tailgate of the 240. Usually it results in total failure of the rear lights when the wires part company.

To help repair these wires IPD, one of our sponsors at the top of the forum, do a harness repair kit.

Bill.

bfrancese · Post by **bfrancese** » 11 Dec 2012, 17:03

Yea doesn't seem to be coming from the tailgate. I'll probably pick up that harness regardless. Stranger still, the speedometer needle only jumps when the car rolls without me pushing the gas. Gonna try a full recharge of the battery.

bfrancese · Post by **bfrancese** » 12 Dec 2012, 12:26

After charging the battery fully it reads 13.5v. After driving it to work it drained to 12.6 pointing to something with the alternator or belt tension I guess. Since it was replaced fairly recently I'm going to double check the tension + hopefully that is it.

Post by **billofdurham** » 12 Dec 2012, 12:42

Have you checked the charge coming from the alternator? A good one should give a reading between 13.8 to 14.2 at the battery terminals.

The belt tension should be checked at the mid-point of the longest run on the belt. Using thumb pressure you should be able to deflect the belt by 1/4" - 1/2".

Bill.

Post by **regent** » 12 Dec 2012, 12:58

Also, you want to check the difference in voltage between +GEN and +BAT. If it is more than 0.3volt, then you should be looking at a poor connection. Even a good alt may not be able to charge the battery well with a drop like that.

bfrancese · Post by **bfrancese** » 12 Dec 2012, 18:30

Is there a handy version of the alternator diagram anywhere? The voltage on the alternator is consistent with the battery and it doesn't seem to jump when revving the engine. Trying to figure out another way to test the alternator.

Currently voltage on the battery and the alternator read 12.3. Warning bulb does not light up. Wonder if there could be a connection issue there? I'm stumped.

bfrancese · Post by **bfrancese** » 12 Dec 2012, 19:00

regent wrote:Also, you want to check the difference in voltage between +GEN and +BAT. If it is more than 0.3volt, then you should be looking at a poor connection. Even a good alt may not be able to charge the battery well with a drop like that.

It was .22

No idea.