2005 xc90 wipers randomly coming on.

[xarlock667]

I have a 2005 xc90 and the wipers are nutz.

Symptoms:
1) They turn on and off without being told to do so.
2) They stay on for random amounts of time, from as little as 10 seconds and as long as 45 seconds.
3) They will NOT turn on with the stick.
4) They will NOT adjust the speed with the stick.

What I have checked:
1) Fuses and Relays
2) The Wiper Switch
3) The Motor

What I have found so far:
1) The wiper switch contacts inside the switch were dirty, I cleaned them with an electronic parts cleaner. I double checked that the switch worked with another xc90.
2) I have power to the fuse, and power to the on/off relay.
3) The on/off relay fires at random. This is not the relay's fault, I have several other relays I have swapped it out with and they all do the same thing. SOMETHING is making the relay fire. More on this in a moment.
4) I checked the motor connection. The Blue wire on the motor is recieving power from somewhere at random. This wire is the source of the on/off to the motor, but I need to know where it is coming from.

I am open to all thoughts and suggestions.
*One more thing, it DOES have HID lights stock from Volvo, I disconnected them to be sure they were not part of the problem.

[swedishdragon]

Are there rain sensors on this model? That could be throwing a false signal. Otherwise, you've checked everything I would have checked!

Any other wiring issues?

[volvo for ever]

CEM- water ingress

[D5Gill]

Originally Posted by volvo for ever

CEM- water ingress

Or could the steering wheel module (SWM) A new one will have to be coded

[xarlock667]

There is a rain sensor, but could it make the wipers come on on their own? Or ignore the manual controlls?

As for the CEM, when I had the cover off the wiper motor, I examined the wiring. It went into a semi-sealed box that I found out later was the top of the CEM. It is possible that water got in it.

Can I pull the CEM, dry it out, clean the corrosion off (Electronic parts cleaner is EPIC) and then just plug it back in?

Can I pull the rain sensor without breaking it or the window? How do I remove the cover?

[xarlock667]

SO, I removed the CEM and cleaned it with electronic parts cleaner, There was a lot of corrosion under the larger of the 2 upper connectors YAY. I got it as clean as I could then reinstalled it. FAIL. It started doing the exact same thing almost instantly. Any more ideas?

[xarlock667]

Got hold of a GOOD scanner.
CEM-8F2D
CEM-8F2E
CEM8F25
PSM-E003
DDM-E010
UEM-0080
DIM-0001
DIM-E003

SO, Any help? Is there a place I can find all the Volvo codes?
ONE more quick question, do you have to program the CEM when you replace it?

[Clan]

Originally Posted by xarlock667

Got hold of a GOOD scanner.
CEM-8F2D
CEM-8F2E
CEM8F25
PSM-E003
DDM-E010
UEM-0080
DIM-0001
DIM-E003

SO, Any help? Is there a place I can find all the Volvo codes?
ONE more quick question, do you have to program the CEM when you replace it?

you have a known fault from about 10 years ago , the cure is a NEW CEM and new top multi-connector plugs , there are two ..also the waterproofing modification Kit to stop more water getting in . You could be talking of £1000 or so , best let the dealer do it properly for that kind of money .

Yes you have to get the CEM original factory software put in the new unit .. second hand units won't work , they hold all the security info unique to your car ..

[diro]

Originally Posted by Clan

Yes you have to get the CEM original factory software put in the new unit .. second hand units won't work , they hold all the security info unique to your car ..

Software can be transfered to the donor CEM
Only 1 condition - donor CEM numbers, "mask" must match original CEM

[SwissXC90]

Originally Posted by xarlock667

SO, I removed the CEM and cleaned it with electronic parts cleaner, There was a lot of corrosion under the larger of the 2 upper connectors YAY. I got it as clean as I could then reinstalled it. FAIL. It started doing the exact same thing almost instantly. Any more ideas?

Water damage can not always simply be cleaned off.

if causes corrosion to circuit board tracks and components, resulting in failling tracks (open circuit) and failled components.

Unless you are able to repair surface mount electronics at component level, with access to the right tools and spare parts, you have no choice but to fit a new CEM