The 75 and ZT Owners Club Forums - View Single Post - Parasitic battery drain

ianM · 25th February 2021, 07:13

OK! So, after following the forum's general voltage drain-related advice, I started pulling fuses out over the weekend, and I think I've found my draw. The only problem is, I don't really know where to start in tracing it.

Originally, the drain I was seeing as about 100mA, after it had been left to settle. All the fuses that seemed to be causing issues were behind the passenger glove box.

Pulling fuse F5 (BCU, wipers) dropped the voltage by 50mA.
Pulling fuse F14 (central locking) dropped it by 10mA.
Pulling F24 (front windows) dropped it by 10mA
Pulling F21 (power seats) dropped it by 20mA
And pulling fuse F20 (fuel pump) dropped it by another 10mA.

Now, I know that some residual drain is normal, so I'm assuming some of these fuses aren't issues. I'm also guessing fuse F5 is my most likely culprit, which the manual simply describes as "body control unit". All I'm wondering is, how do I go about tracing the fault with the body control unit? And which of the other fuses are normal drains, and which need to be investigated further?

25th February 2021, 07:13	#4
ianM Regular poster Rover 75 2.5L V6 Saloon; Rover 214i Join Date: Sep 2010 Location: West Midlands Posts: 86 Thanks: 18 Thanked 1 Time in 1 Post	OK! So, after following the forum's general voltage drain-related advice, I started pulling fuses out over the weekend, and I think I've found my draw. The only problem is, I don't really know where to start in tracing it. Originally, the drain I was seeing as about 100mA, after it had been left to settle. All the fuses that seemed to be causing issues were behind the passenger glove box. Pulling fuse F5 (BCU, wipers) dropped the voltage by 50mA. Pulling fuse F14 (central locking) dropped it by 10mA. Pulling F24 (front windows) dropped it by 10mA Pulling F21 (power seats) dropped it by 20mA And pulling fuse F20 (fuel pump) dropped it by another 10mA. Now, I know that some residual drain is normal, so I'm assuming some of these fuses aren't issues. I'm also guessing fuse F5 is my most likely culprit, which the manual simply describes as "body control unit". All I'm wondering is, how do I go about tracing the fault with the body control unit? And which of the other fuses are normal drains, and which need to be investigated further? Last edited by ianM; 25th February 2021 at 10:02..