bricem13

Hi

I found my 90 c2 a couple of times with dead battery... I identified a 130mA drain and used the fuse removal method to identify it but none is responsible of the drain...

I checked frunk and engine fuses. Ccu fan stops correctly and doors contact were renewed. When I checked doors were closed but not locked.

Any hints ?

Best regards

djantlive

I had a drain when heater control valve was stuck. You may want to see if there is any part under the front or rear bonnet that is warm upon a cold start.

Also, bad connection for radar hardwire or stereo can dran as well

gfunk

Do you have a set of schematics? I'd start at the battery and try and determine which of the buses has the drain on it. There appear to be several power buses (labeled 30, X, 15, 31), some are fused and others are not.

PM if you need schematics from the manual.

ToreB

You have to lock the car in order to get reliable measuring results.
Maybe a failed door switch. Are the interior lamps shutting off as they should?
If you have the tachometer with the OBC option, the backlighting in the LCD shall shut off when locking the car. If not, it might be due to an internal fault.
Cheers,
Tore

apanossi

Not sure if this applies to you but I had a similar drain that would diminish when pulling the radio booster fuse. Turns out that there was an internal drain in one part of the loom behind the dash that was for the old factory phone. It's a short segment plugged into a splice of the main loom. Once I eliminated this piece, I was able to get a normal current draw with the fuse installed. I can post a pic of this small piece when I get a minute for those who are curious.

bricem13

Thanks for the replies. Taking out fuse 11 (inner lamps) reduces the drain by 10mA... Doors switches are new and lamps shut off correctly... I have the schematics so will look at them.

Best regards

VR6-er

I had the same issue. It was the frunk light fitting.

Earlydays

Easy to test if the light is staying on after the hood is closed....the surface right above the light will be hot to the touch.

HiWind

I love those elegant little simple answers

tdiquattro

To make the car more reliable and reduce drain I did the following.....

Upgraded the door switches. https://rennlist.com/forums/964-foru...grade-diy.html

removed the window relay and replaced with a link plug
removed the frunk switch - awaiting fitting of 996 frunk catch with built in switch
removed the glove box switch and wired the glovebox light to the door switches
removed any unused clock warning lamps
removed all of the factory alarm/immo
replaced all interior/dash lamps with LED
cleaned all the earth points I could get to.
unplugged and cleaned all connectors in the frunk - abs,etc
removed all relays/DME/rear window heater/spoiler controller/central locking control/etc, took the covers off and re-soldered all of the connections/pcb pads

The only drain I have now is my aftermarket alarm and tracker, and my windows open all the time instead of having a mind of their own.
I am now running an smaller cup sized battery.

bricem13

Had a drive so recharged and reconnected the battery. There seems to have a relay stucking when connecting the battery but this relay is not in the fuse box, seems to be somewhere closed to it... I will investigate further with working schemes.

Richard Curtis

Also worth checking:
-- Glove box light stays on
-- window switch stuck in the up position

bricem13

I took alarm module off and drain went from 150 to 70mA, sticking relay inside. I opened the module and found a broken resistor and 2 black places on the circuit board. Continuity is ok so I will try to replace the resistor.

Earlydays

Is this the alarm module behind the right hood hinge?

bricem13

Yes