E39 525d battery drain - 'hedgehog' problem?

[Rouleur]

I'm asking this on behalf of my parents' friend but I think I've got all the relevant info - it's a 2001 525d.

The old battery was draining pretty quickly so it was replaced but the new one is just the same, plus with the key out of the ignition the heater fan continues to run on slow. Also the fuel gauge shows empty all the time.

I've had a search around the net and it looks as though a common cause of the battery problem is the Final Stage Resistor or 'hedgehog' - is this the likely source of the problem? They seem to be cheap at ~£50 but is there a way of checking before replacing it?

TIA

[E30M3SE]

If the fan is running all the time then possibly, not sure re fuel gauge reading zero, that may be another issue.

Unplug the FSR and see if the problem goes away, better still measure the drain with the FSR connected then diconnect and remeasure.

[Dave_newcastle]

Battery drain and fan running is what my 525i had - changed the hedghog (takes no more then 15 mins) nad problem was solved - so from what you describe I definately would invest in new hedgehog

[miniman]

Agreed, Hedgehog should sort the fan and battery drain. Fuel gauge could be the ignition switch (causes all sorts of chaos).

[Rouleur]

Thanks for the replies, I'll tell him to source one asap