[Arron123]

Hello.
My bmw m135i 2016 5 door has recently been playing up and was wondering if there is any out here that could possibly point me in the correct direction.

I have been waking up on the morning to a dead car. I attach jump leads and the car fires up straight away without any issues.
I could previously hear the water pump running while the car was switched off and for quite some time after being turned off aswell. ( even while the car was going dead)

I went to the mechanics explained the issue he suggested me to replace my battery and if it still happens to replace the water pump. I did both ! And the problem still was happening it started again after about a week.

Prior to this I replaced my ac Compressor. The ac Compressor that was fitted into my car was apparently the same but with different plug pins. However it was still fitted.

In the past few days. Sometimes the car goes dead and sometimes it doesn't. Example I woke up one morning the car was not dead. I drove the whole day going different places car was fine. In the evening went for a meal came out from the meal around 1 to 1 hour 30 mins later and it was dead.
Since I replaced the water pump I dont hear it run anymore after it's switched off
All my coolant levels are correct there is a slight leak somewhere which I have to top it.up every other week

Also to add when the car goes dead the heaters work perfect
However when the car has power and does not go dead the heaters blow cold air and the car has a message that pops up after about an hour saying engine temperature high drive moderately to cool the engine along these lines. That stays on it doesnt go to the next message which is the red alert to pull over.

I've recently got it diagnosed by bmw and the outcome had only 1 fault. Ac Compressor break in the circuit power supply high

Could anyone please advise me before I spend £££ replacing yet another part which may not be the solution

Thanks in advance
Located in UK England 🇬🇧 right hand drive

[DomMuc]

measure the drainage .. if there is drainage ( more than 80mA) .. start pulling the fuses- if drainage after Pulling a fuse is gone .. put all ohter Fuses Back in - confirm that drainage is from that fuse by plugging it back in - see Fuseplan for units this fuse is for . check drainage by unplugging units - repalce/ repair defekt unit