92_964

I'm trying to troubleshoot a drain on my battery which will take the car from 'fresh-charge' to 'unable-to-turn-the-starter' in 2 days. I've read several RL threads and A.S.'s book (p. 383+) on chasing this sort of thing down, but apparently am missing something. Maybe you guys can help? Details are:

I'm using a new DC ammeter of the claw design...instructions say to only enclose 1 wire at a time in the claw. Of course, the + battery cable splits into the two + leads so close to the clamp that I cannot enclose both wires at once, so I'm reading them separately.

I have a 14-month old Interstate & 1-year old alternator. After topping-up the battery with a trickler here is what I read on the ammeter:

+ battery cable 1 0.27-0.31A
+ battery cable 2 0.27-0.31A

The only other cable running from the battery goes to my stereo amp (photos posted in other threads) and reads 0A on the ammeter. What has me stumped is that while removing fuses 1-41 no ammeter readings decreased. I'd appreciate your thoughts on where to search next. I realize there is no guarantee that a young battery = a good one, but it does perform fine if I drive at least every other day. As a control, I opened the engine lid to confirm that the light's drain showed-up on my meter (which it did @ 0.65A)

Photo included...

ToreB

Personally, I prefer in-circuit amperemeters, not the clamp-type. These are more reliable when measuring such small DC currents.
Try pulling Fuse 1, 28 and 17, all at the same time. If the current goes down to below 50mA (0.05A) I would suspect that the CCU does not shut down as it should. This could also be determined by a permanently running CCU fan, if the fan is OK.
If this is the culprit, a transistor must be changed inside the CCU, an easy task for an guy with some experience with a soldering iron. Here's how: http://www.bergvillfx.com/ccurepair.html

Normal drain with the CCU T1 fault, and with a working CCU fan is about 500mA. (0.5A) If your measurement is reliable I would guess that the fan is not working, and you see the CCU current drain only.
Cheers,
Tore

Rocket Rob

270 milliamps is too high. You should be between 40-60 ma. I had this happen to me. Tracking the fault is not difficult but is tedious. First, be sure that your trunk and interior lights are turning off. Then start pulling one fuse at a time and watch your meter. When you hit the circuit that has the fault, you should see the current draw drop. In my case, it was as Tore describes above as a fault in my CCU.

FeralComprehension

+964.

On my car I traced it to the glove box lamp switch.

Luck!

92_964

Thanks, all - tonight's progress: 1st) the glove box, engine and trunk lights have been and are still off, 2nd) pulling fuses 1,17,28 simultaneously made no difference, 3rd) figured-out that by removing the ABS cover I can get the ammeter around the ground braid, 4th) at the suggestion of my local mechanic I removed ALL fuses and the drain essentially stopped. The drain did not return upon reinstalling fuses, so I think this tells me it's a fused process which may only run (continue running) after turning the car off...and the battery is likely ok. I'll soak on that tonight.

Reinstalling the fuses also made me notice that 2 fuses were incorrectly sized so I replaced them...which may keep from toasting the A/C Condensor Blower and the Sunroof motor.

Question...should one expect to be able to hear this CCU Fan that has been referenced by Tore and others if it is running with the engine off?

Vandit

Make sure your interior lights are coming on when you open your doors after you've turned off the ignition. If they aren't coming on, the car is not registering that you have exited the car and it keeps power to the power windows and will drain your battery w/ the quickness.

That's what was happening to my car and simply messing w/ the switches on the doorjam fixed it, plus now I keep an eye out to make sure my interior lights are coming on when I exit the car.

92_964

I'll experiment with that...I typically keep them in the always-off position to avoid problems if I ever fail to completely shut a door in the garage. Does cycling the switch register or does current have to flow? In any event, thanks...this would not have occurred to me. (I did read about sticking switches being a source of pain in one thread and confirmed they're working smoothly.)

ToreB

A failing door switch will not only keep the interior lights on, but also keep alive other things such as the power windows. The CCU fan will run for up to 20 minutes after ignition off, details on this are given on my web page linked above. It's easy to spot or hear it if you take a look under the dash behind the CCU.
Cheers,
Tore

springer3

Do a search - there are lists of things that cause battery drain. Mine was the spoiler controller, which worked fine, but was leaking a bit of current through a weak-but-not-failed "extend" transister. A real bugger to find, for sure.

92_964

To follow up, switching the interior lights from always-off to on-when-doors-are-open position (and being sure that they light-up when I exit the car) seems to have made all the difference...I let the car go 5 days without driving and no charging and it started great...no noticeable decrease in the battery. Thanks for the advice, guys :-)

I also noticed that Tore's TLock activates the interior lights when the locks are cycled...could be handy if you have a flakey door switch.