2007 Diesel E70 X5

Jakeo · Post by **Jakeo** » Wed Jul 06, 2022 9:28 am

Hi Everyone, new member from Australia.
I have a weird one.
Battery is in great condition but tends to go down to 9.5 volts and hence no crank, i have sourced it to being the cut off relay in the rear fuse block staying energised and getting quite warm even after many hours of being parked and vehicle locked.
I have the Foxwell scan tool specifically for my model so can do some hunting if anyone has a clue as to why the relay wont disengage.
Many Thanks
Jake

sapphireblack · Post by **sapphireblack** » Wed Jul 06, 2022 10:37 am

Wouldn't replacing the relay be the first option?

btw

X5Sport · Post by **X5Sport** » Wed Jul 06, 2022 5:30 pm

Hello and

Could be no more than arcing has caused a buildup on the contacts and it’s stuck on so effectively shorted to on permanently. Try pulling the connector off it and see if it click open. You can also use a meter to check if the switched contact is closed even with power off. That tells me it’s likely to be a faulty relay. If you replace it and it’s still engaged then you need to start tracing back to where the switching current comes from, or use the Foxwell.

Jakeo · Post by **Jakeo** » Wed Jul 06, 2022 9:56 pm

Thanks sappireblack and X5Sport.

Pulled the relay out and removed cover to check contacts, sadly they are clean as a whistle, it has a very distinct click when i insert and remove the relay so something is telling it to stay energised and i,m guessing there could he more than answer to that. Is there a link for me to view a wiring diagram that you may know of at all? Thanks.

Alan Gunn · Post by **Alan Gunn** » Thu Jul 07, 2022 6:48 am

Not the hedgehog or FSR is it.

Jakeo · Post by **Jakeo** » Thu Jul 07, 2022 8:02 am

Alan Gunn.
Hedgehog?? Isnt that a biscuit? Not sure what FSR means either,i,m Australian lol

sapphireblack · Post by **sapphireblack** » Thu Jul 07, 2022 10:15 am

FSR is final stage resister iirc.

Hedgehog is a term used for a troublesome heater component that used to be the cause of issues on the earlier E53s. But I think only recently it was determined the E70 didn't have this.

Any aftermarket accessories fitted? It's been known for some to prevent the car from fully shutting down.

Jakeo · Post by **Jakeo** » Thu Jul 07, 2022 11:34 am

Thanks for clarifying sapphireblack.
After some research it would appear that the cut off relay remains continually energised until battery voltage becomes critically low and then disengages, so today i have replaced the battery as it may have been older than what i thought. And yes i have fitted after market headrest dvd,s but have wired them through the lighter socket so will power off with the ignition. Have reset all 34 fault codes including sunroof and DSC that came
up after battery change and car runs great, hopefully the new battery will stop the cut off relay from dropping out and will stay energised and not lose my date / time and many other settings, fingers crossed, i will post an update after a few days of vehicle not being used as i will be away with work and not using it.

Graeme · Post by **Graeme** » Thu Jul 07, 2022 11:00 pm

Hello,

Did you code your new battery to the car? I had a 2008 E70 that had to have 2 batteries during the 10 years I owned it - I believe both needed to be coded to the car so the smart charging system worked properly.

Jakeo · Post by **Jakeo** » Fri Jul 08, 2022 5:20 am

Hi Graeme.

Thanks for that info, not entirely sure how to do that but i will plug in the code reader and see if there is an option for me to do so.

Jake.

sapphireblack · Post by **sapphireblack** » Fri Jul 08, 2022 6:01 am

Coding the battery is a good call, its rather essential as it helps the intelligent system charge correctly.

I remember well when I first got my X6 it needed a battery, the non franchise dealer was willing to supply one but no more. I opted for a main dealer battery supply and fit and got a proportionate refund. The IBS system exists for a reason, unless of course BMW create work for income

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