Tailgate washer pump without electricity

Franz47 · Post by **Franz47** » 19 Apr 2018, 12:50

850 TDI station wagon 1997. My tailgate wiper works, the washer has ceased to work some time ago. Today I found time to investigate. The cause is, that the pump does not get any electricity input from the plug. When I press the button on the wiper switch, the wiper starts but there is no voltage on the pump arriving. Ground is ok. Fuse ok.
I have the wiring diagrams and can see that there is a line from the switch via relay to the tailgate washer motor but it is not clear for me weather the wiper voltage is activated via solenoid or just via push button on the switch.
Any hint how to proceed best?

Post by **scot850** » 19 Apr 2018, 14:28

Have you tested the motor itself? The motors tend to fail fairly frequently, even Volvo ones, as we don't use them often enough. There are some aftermarket versions out there for not a lot of money, but first thing, remove the pump and see if it works when you power it up.

Neil.

Post by **jvl** » 19 Apr 2018, 15:32

+1 on Neil's advice.
I had a similar issue: my wiper would work on pressing the button, but pump would not.
The fault was with the pump itself. Here is the link to another topic I also found very helpful to get mine going:
viewtopic.php?f=1&t=79480&p=433395#p433395

Joost.

Franz47 · Post by **Franz47** » 20 Apr 2018, 02:05

Thanks for the input. The pump was my first guess also, since I could not hear a sound from it. But I removed the pump, then the plug from the pump and checked for voltage when the button for rear screen washing and wiping was pressed. Nothing. Only the wiper worked for several cycles as expected. There is just one suspicion I now get. Did I check the correct pump?
In the VADIS DVD there are two entries for "replacing windshield washer/wiper components. When looking into both today I find that the pumps for the tailgate window are located just vice versa in the two entries. So I think I have checked the wrong pump.......

Post by **jvl** » 20 Apr 2018, 13:37

Aha, checking the wrong plug/pump would explain! I remember pulling out the pump and trying it on the workbench (you can use an external 12v source directly connected to the pump).
Mine did not run. Opening it up and cleaning and greasing its internals solved it for me.
I then tested if it would actually pump by holding it (not entirely!) in a bucket of water.
I hope this is the cause of your problems: from what I read, changing out the stalk isn't too much fun.
Good luck!

Post by **BEJinFbk** » 20 Apr 2018, 14:05

If the wiper is cycling, the stalk is OK.
The wiper relay sends out power to
the pump for a wash input as long
as the switch is held.

I'd agree that a bad pump is most likely the
issue. Just be sure to check the right one.

Franz47 · Post by **Franz47** » 27 Apr 2018, 13:56

I have purchased a new pump for 15 € and will replace it when I find the time. Checking the wrong pump must be the explanation.

Post by **jvl** » 28 Apr 2018, 15:20

Glad to hear you found one. I'd be curious to hear how a new pump works out for you!

Joost