B3 E36 Battery Bad Drain (Parasitic)

[HiteshG24]

Hi Folks,

Hope you're all well,

I have an alpina b3 e36 1994 for the last several years, since ive owned the car there has been a battery drain.

Things i have checked/replaced :

- New alternator
- Removed glove box, boot and bonnet bulbs
- Checked wires in the that go to bootlid for broken/crushed cables
- Alarm not activated
- No lights, ignition or stereo left on
- Brand new battery
- Disconnected old tracker

Running out of options, any help will be massive help.

Thank you

H

[JohnW]

Sometimes the fan speed control resistor goes faulty and activates when not in use. There are two different types from memory, it is the models that have digital climate with the variable fan speed, not the ones with the basic fan switch. The resistor is commonly known as the hedgehog. It’s another possibility, usually fails on the E46 but can do in the E36 too.

[Charles]

Sometimes the fan speed control resistor goes faulty and activates when not in use. There are two different types from memory, it is the models that have digital climate with the variable fan speed, not the ones with the basic fan switch. The resistor is commonly known as the hedgehog. It’s another possibility, usually fails on the E46 but can do in the E36 too.

This!

If the hedgehog is failing then you may notice unusual fan speed behaviour which is normally the first indicator of a problem. Unfortunately it is a PITA to get at via the drivers side footwell, unless you are a contortionist with small hands. Fortunately it is a cheap fix.

[HiteshG24]

Hello all,

Thanks for your help,

After hours and hours investigation, it appears the immobiliser brain had a short compactor which was draining the battery. I have now decommissioned old problematic alarm and replaced with new alarm.

No more excessive power drains

Thanks again

H

[JohnW]

That’s not a bad outcome, I assume you meant ‘capacitor’? I would have been tempted to swap the original, but it’s very old, likely something else may have gone on it. I think the later E36 originals were a dealer fit option 3G EWS by Serpistar, square fob with corner cut off shape.

[AG]

which B3 do you have?