Washers on with wipers! How to fix?

[960CD]

Hi,

I have a usual fault that has started this morning on my 07 XC70 D5.

When I put on the wipers the washer jets spray continuously.

I recently replaced the washer pump but today is the first time I have this issue.

Any ideas on how to sort this?

[XC70Bob]

I think the wash/wipe circuit is the same on the 07 as the 05



Washer pump does both front and back it just runs in different directions for each, its driven directly from the CEM as shown in the diagram (6/1227 is pump ).

So unless its a fault in the switch on the stalk or you have it pulled back to do a wash and its jammed then I would be a fault in the CEM , on this year all relays are internal to the CEM to no user replaceable.

You could try pulling fuse F34 in the CEM to stop the pump as a temporary fix.

Have you checked the pump to make sure you have not damaged any wiring when replacing the pump.

[960CD]

Thank you XC70Bob.

The diagram will come in handy. I’m away so pulling the fuse will be helpful for a quick fix in the rain.

The pump and washer keys work fine on pulling the stalk to clear the windscreen. But in rain the pump is running with wipers on and the tank is now empty.

Where is the CEM and can I just replace it with another of the same part number?

[960CD]

I don’t have a 34 fuse on drivers side fuse box. In fact most are empty.

Where could I look?

[4x4]

Fuse 34 is under the steering column/above the pedals

[960CD]

Great, thank you!

[XC70Bob]

No you cant just replace the CEM everything is coded to it.

If it does prove to be the CEM that faulty then talk to volvo diagnostic ( https://volvodiagnostic.com/ ) They do CEM repairs.

[Joe Harding]

STOP. Don't start pulling control modules yet!!!

We had exactly this fault in our last car. It's easy to explain. The washer/wiper control has a digital encoder switch to send a few bits to the relevant computer. e.g. 1100 means 'I want variable wipe' 1101 'I want washer jets' etc. (BTW binary codes made up but you get the idea.)

If there is wear in the switch so that the extra bit is activated accidentally, it puts the washers on continually. Exactly our problem.

Here's two fixes. Cheap - get some contact cleaner and lubricant. (Some people use WD40 but I prefer the electrical switch cleaner.) Insert straw down back of switch and wiggle it around a few times. Fault may well now clear. Ours did for a year, then came back, Repeated the exercise and bought a few more months.

Expensive solution, buy a new switch. Easy to install, no need to remove steering wheel like Haynes manual says. Problem solved for another 100k miles.