utahrock

I've got a turbo and the battery started to discharge faster than normal while sitting, so that I can only go a day or two without a battery tender. I checked the amperage (with everything off and key out) and it is 110 mA.

Trying to find the problem, I pulled every fuse and relay in the front and rear boxes, to no avail. Then I disconnected the smaller harness cable from the positive battery terminal and that wasn't it, either. So the current is going out one of the two big cables that are attached direct to the terminal clamp. I'm guessing one goes to the alternator and one to the starter?

Any ideas what it could be and what to do next? Thanks!

NC TRACKRAT

Just an amateur here but the feed to the starter has to go through the ignition switch and that may be where the problem lies.

budge96

I had a drain a few years back like that on a prior TT and if your car has yet to receive an
updated engine harness it may be something to investigate..
I just happened to be checking my alternator and removed the alt from the harness under the shroud and BAM the frayed look of the harness literally scared me ! I think I had the car
Flat bedded to the dealer to address the harness once they had taken my VIN and
Determined it had yet to be done...FYI , Bert

Cemoto

There have numerous threads here about issues, one of the best was started by Alex, I didn't find it when doing a search but found this one instead.

Hope it helps!


https://rennlist.com/forums/993-foru...se-help-2.html



.

deekay911

I had a fast drain issue that turned out to be the ignition switch (electrical part at the back). One symptom was that the radio wouldn't fully turn off after switching off the ignition. Easy diy to replace if you work in a circus, part is $100.

ToreB

The most probable cause for a 100mA drain is failing door switches. These does not only activate the interior lights, but a relay or two as well as the alarm/door lock control module. Turning off the interior lights masks this problem.

Another common problem is a failing on/off transistor in the Climate Control Module. This can leave the unit on. (it is supposed to shut off in 20 minutes after ignition off) However, this is normally about 500mA due to the CCU fan. However, if the fan has failed you could get about 100mA. Pull Fuse 1 to test.
The tachometer OBC LCD backlight circuit can fail to shut off when car is locked, this is also a probable cause for this current rating.

Be sure to measure the current with all interior/bonnet/engine lights off, lock the doors, and wait for the CCU to turn off. The light switch in the luggage and engine compartments are placed in the lock mechanism. Depresss the latch to switch off the light.
You might consider opening the windows first to avoid having problems getting in due to a problem with immobilizer or similar.
Normal current draw at ignition off is normally around 20-25mA. Depending on aftermarket equipment installed, (alarms/stereos etc) this can increase to 30-40mA.

Cheers,
Tore

sugarwood

Is 110ma considered too much?
Did you pull the fuses one by one to isolate?

FGL28

My car kept draining the battery because of the computer in tachometer. North Hollywood Speedometer diagnosed it and repaired it.

utahrock

110mA is too much; it should be around 25. As stated in my original post I did pull every fuse in the car and none reduced the current. So I'm thinking the ignition switch suggestion may be the cause, since there is an un-fused hot wire to it. So in the next few days I guess I'll be summoning my inner-contortionist.

Thanks for all the help and suggestions!

hoggel

I am happy to see you still have the car Rock. Sorry that you are having trouble with it. Do you have the schematics? Do you know if there are different wiring diagrams for the turbo?

The 97/98 diagram I have shows two cables from the battery, a 6.0 Red and 4.0 Red/White. The Red/White goes to the ABS and has a 60A fuse #46 that is in the front left of the car near the ABS pump. The Red wire goes to a 60A fuse #47. I don't know where that one is.

utahrock

This is just a minor problem-I love the car. But when working on it I sometimes fantasize about getting revenge on dumbass engineers who never consider that the thing may need to be taken apart. I just installed turbo check valves and getting the muffler brackets off and back on, not to mention undoing the oil lines on the engine had me wishing for small, delicate hands that could operate in miniscule places.

I don't have schematics, but it would be great to get some if you have them. Thanks!

hoggel

I have the NA manuals/schematics that you are welcome to borrow. I edited the post above.