chewg

I've been having this nagging problem for sometime now and I am giving one last attempt before I send it to the shop. I despise being defeated by the electrical gremlins.........

Here is my problem. I have a battery drain issue. I measure the battery drain after 20 mins of shutting down. I connect one terminal to the -ve cable and then the other to the battery post before I disconnect the battery - this allows any battery drain from relays to be measured.

With this method I have a constant drain of ~150mA (no wonder my battery dies ater a 1-2 days). I started pulling the relays and fuses one by one and managed to track down the 4 items that drained ~10-15 mA:
- R11 clock
- R12 diagnostic rear wiper (?)
- R28 control unit (CCU?)
- R35 DME
So, this accounts only approx ~40-60 mA of the ~150 mA. None of the other relays or fuses showed any measurable curent draw. What's causing the other ~100 mA draw?

Work on the car over the last 6 months:
- a/c conversion to R134a
- swapped out CCU
- attempted to replace radio (hence radio came out of the car) but re-installed since I could not find a radio I liked.
- installed "Priority Start", but for this exercise, I removed this item completely.
- replaced alternator (the battery charges after each run, so I know the alternator is functioning good).

The problem did not just "appear" after one of the above work, so I am totally baffled. Any help appreciated!

Happy ThanksGiving!

GG Allin

Personally, I gave up and went with a deep cycle.

Sten

A drain of ~150mA shouldn't flatten your battery in two days - that works out at just over 7A drain for 48 hours. Are you confident that your battery is OK?

robbed666

Agree with Sten, you should be OK for a Week.

wsybert

Have the battery load tested. A lot of auto stores will do this for free. I agree with the other comments. That is not a drain that would flatten a battery in a couple of days if the batt is good.

eddychan

check your boot/truck light. Sometimes it stays on without being noticed.

Eddy

chewg

Thanks for the advice

Will get the battery checked, but I read on this forum that drain should be somewhere around ~90mA or lower. I remember a long time ago (way before I had this problem) I checked and the drain was around 50 mA. So I am still interested in trying to find what causes the (relatively) high drain.

Eddychan, trunk light was disconnected for this exercise. Thanks.

Richard Curtis

Chewg: also check that the glove compartment light isn't "on." I've also had a problem with a window switch sticking in the "on" position (remove the switch, disassemble it, and clean it. Very easy). Both of these led to battery drains, as did the interior lights not going off; I haven't found the cause of that yet (I did replace both door jamb switches).

skruggs964

chewg....I noticed that you bought a CCU unit on eBay. My buttons on mine are all worn....and I'd like to eventually replace them. If yours are in good shape, are you interested in selling your old CCU unit?

chewg

This is really silly now..... I am sooo embarassed!

I have been trouble shooting my battery drain using a faulty multimeter! Now with a new multimeter, my drain after 20 mins of shutting the engine is around 18 mA When the car is running at idle, the alternator is charging the battery at 13.7 volts. The battery holds charge but just........ I left it overnight and it dropped from 12.5 volts to 12.2 volts. So, it is a no brainer that the battery is on its way out......

Skruggs964, I bought the unit just for that reason...... the buttons on mine are all worn out too and having a 2nd unit may come in handy at some point in the future. I tried searching for just the buttons but no success. I even thought o getting stickers made just for the buttons but never got further than having the thought. Sorry....

Thanks all for the great advice.

DustinTarditi

I had a bad wire in my harness that would periodically discharge the battery in a few hours... hard to troubleshoot - ended up taking it to my wrench after a few batteries were eaten up.

John52

There several threads re: battery drain and the CCU. That was my problem.
A common issue is the internal fan that doesn't shut off. In my case it was the fan AND one of the servo motors that were staying on. Like you, my battery would be dead after a couple of days. Pulling the fuse for the CCU was a quick and easy way to determine if that was my problem. When I removed the fuse, there wasn't any drain on my battery.

chewg

After may tries, I've finally figured out the battery drain problem..... there were several and having worked each one, the car is now only having a drain of 20mA!

The first problem was the alternator......... replaced and it was charging at 13.7V.

The 2nd problem was a stuck passenger side interior light switch at the door jamb. Cleaned out the switch and bought new rubber caps.

The 3rd problem was the hood light. When the hood is opened, the light never came on and I assumed that the bulb was burnt. Bad assumption, the buld was good but the light came on only when I closed the hood. The reason is that the wiring harness has developed a kink and frayed such that it shorted only when the hood is closed turning the hood light on! Took me a while to figure this out....... Now taht I have repaired the wiring harness, life is good!

Thanks to all for the great advice!

Merry Xmas and Happy New Year!

robbed666

Good news!

I know what you mean about the hood light. I connected a buzzer across tmy hood lamp. For two reasons, 1. to make sure the hood light was off. 2. To make sure the hood was locked down properly.
Drove the car, when I first got it for a 100+ miles, relying on the safety catch!Had a hood catch fail on my 69 Mustang, ripped the hinges from the inner wings

bwoodry

My Glove Box light would come on when the door was shut,,,I changed the switch and presto,, all fine now...