SOLVED: Rear window washer pump not working
 

SOLVED: Replaced the pump and it is working now.
Hi all,

Trying to diagnose this issue. Rear wiper works fine, the other two washer pumps work fine. Only the rear window pump doesn't work. The wiper kicks in but not the pump. Tried a second hand pump pulled from a 2010 E61, it does the same, doesn't run.

Quick question, do these pump work on normal 12V? I pulled all 3 pumps from the donor car and tried them directly with 12V and none of them work. I feel like its odd that all 3 wont work. At least the front windscreen pump makes some click sound when I connect it to 12V, but nothing else.

Looking at the wiring diagram, the power to both windshield pumps come directly from "Basic Body Module", so there is no direct replay or something.

While playing with multimeter, I tested voltage at both connectors (front windshield pump and rear window) unplugged and I see no voltage, then I plugged the front windshield pump to its motor and it works fine which makes me believe that KGM sends voltage only if it detects load (pump) at the end.

Any suggestions?

thanks

I have the same issue and got to the same point in the diag process as you. It was low priority at the time so I stopped working on fixing it. I have the car on the lift right now for some other stuff. If I have time I’ll take another crack at it. If I figure it out I’ll let you know. If you happen to get it fixed before me, please PM me the fix.

Thanks for your follow up RCB. The only relatively cheap fix I haven't tried is a new pump. If you happen to try that let me know how it goes. If that fails, the only FIX that works form what I have seen online is replacing KBM (body) module.

Just FYI so that people know how these pumps degrade overtime
This is how both the pumps I got from junkyard 2010 E61 looked like, no wonder why they didnt run when connected directly to battery. Comparing to these, wonder how the state of the pumps in mine are.
Contemplating whether to change all 3 pumps for future peace of mind and not to overload the circuit with failing/working hard pumps

https://cimg7.ibsrv.net/gimg/5series...a9daeb4f4e.jpg