Windshield Washer problem

J

javis20

Active member
 Hershey, PA USA
Obviously it's not working. Fuse is good. Pulled out pump and checked resistence. Its only 1 ohm. Possibly a short. Put 12 volts on it and it doesn't run. So i guess pump is bad.

However, I also checked voltage at the plug, with the pump removed, and it's 9volts ... even with the car turned off, i have 9 volts on that plug. When i turn the wipers on to spray washer fluid the voltage changes to 12v.

Doesn't seem right, any suggestions?
 
You should be able to hear the pump if it's working - even if nothing comes out!

The most common problem is the filter on the pump that sits inside the fluid reservoir getting gummed up with slimy gunk! It happens when people use different brands of washer fluid and they react. Happened to my E46 and current E86. I'd try pulling the pump out (it's a push-fit)and having a look - you won't lose much fluid if you have your finger ready to cover the hole! :lol:

Good luck getting them sorted. :thumbsup:
 
I've already removed the pump and tried on another power supply. Pump does not work.

My concern is, why is there 9 volts on the pump plug wire even when the car is turned off.
 
Maybe worth eliminating the washer relay?

https://www.realoem.com/bmw/enUS/showparts?id=BT53-USA---E85-BMW-Z4%203.0i&diagId=61_4105
 
Few things don't add up here, first one being that if the pump really is 1 ohm then it would draw in excess of 10A from the supply and will blow the fuse (assuming that circuit is on a 5A or 10A fuse). How are you putting 12V on to test it?

I suspect the reason you are measuring 9V on it is because the wire you believe to be 0V isn't really 0V, basically it has a big resistance between itself and earth. You can sometimes find this sort of thing when it is the 0V wire that is switched rather than the more conventional 12V or when the fuse is blown as per above.

So, rather then measure across the pump terminals, measure each one to a known 0V (either chassis or the under-bonnet 0V charger connection etc) and check all your fuses.
 
Installed a replacement Uro washer motor, works perfectly now. Took the old motor appart to find that it was rusted solid due to washer fluid leaking into the unit. I used my plier to free up the shaft and the old motor started working again.

And yes the resistance was approx 1 to 2 ohms, but remember this is an inductive load. I previously tested the unit with a 24vdc benchtop power supply in our lab. When the motor was frozen it would pull down the voltage to 2.5VDC.

Still not sure why there was 9vdc on the connector when the motor was not powered. I will check again this weekend and I will also check if that occurs on my 2011 E89.
 
javis20 said:
And yes the resistance was approx 1 to 2 ohms, but remember this is an inductive load. I previously tested the unit with a 24vdc benchtop power supply in our lab. When the motor was frozen it would pull down the voltage to 2.5VDC.
Click to expand...

An inductive load makes absolutely no difference when you are powering it with DC. What was happening with your 24vdc lab psu was that it was not able to supply the current asked of it so it 'folded back' the volts to 2.5Vdc. Had that been on a 12V battery it would have drawn over 10A which would have blown a 5A fuse. A 10A fuse might have survived but it would have got stinko hot.

Anyhow, glad you are all back up and running with a nice clean screen again.
 
You must log in or register to reply here.
Back
Top Bottom