Just wanted to give a final update. Powered the TCU trough a relay related to ignition switch position. Car can now be left parked for over 10 days and fires up like a dream. The Bluetooth module / function still work like they always did, great!!



If anyone should ever need a guid on how to manage this issue, I would take a picture and explain what's needed.

A guide and picture would be great! :excited:

There you go...at least a picture of the work. The relay is on the left with green/yellow/white wires. Basically I set it up the way that the new relay is powered by the relay of the rear defroster, which gets power only when you turn the key. If i remember right, the white color wire of the relay is supposed to be connected to "-" and the yellow one is "+" which i got from the rear defroster underneeth the green relay.

Once activated the relay closes the connection between the green wires which I connected with the stock fuse source (red cable) and powers the TCU unit. Obviously i installed a 10A fuse on the red cable....


It's not the cleanest of solutions but it's 100% reversible in any moment - that was my priority.

That is freakin awesome, great engineering and I’m sure something that will be put to use many more times as our X’s continue to age ☹️


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Thanks for the kudos! I'm planning to keep this car for at least another 10 years so... I will have to stick other "patches" here and there for sure:D

You should add the terms "battery drain" and "solved" to the thread title just for people searching. This is a great solution to a fairly common problem. Nice work.

I heard that, that's why I did my own VSS job! - I've had mine for a bit longer than 6 years now and planned on keeping it "forever"... but I've fallen in love with a blue 2012 X5M... that my wife DOESN'T want me to have.


After all the "fun" I have had with my current E53, she has no idea why I would ever consider owning another one :rolleyes::rolleyes: LOL... I tell her it's because the things are so damn hard to hate! I know the enjoyment my current X has brought me, I can only imagine the enjoyment that 550 HP of TT power would bring me :rofl: That's when she quickly reminds me of the whole new set of problems that I would be taking on... which is why I haven't bought one yet... hhhhhuuuu

I see your point:D Actually I would be probably thinking about a upgrade too, if money was all around me. That's not the case and actually the whole family loves the car and I enjoy repairing it so... looking forward to another 150.000miles :-)

Pulled out the TCU on my 2006 x5 e53 and it seems to have solved the flashing screen on my head unit and the battery drain so far *fingers crossed*

So turns out the flickering is back after really wet humid weather even without the TCU, haven’t been able to check the power drain as have been driving it everyday... no idea!