2005 XC70 need help diagnosing wiper problems

[dreiher2]

I get a CEM-8F21 code. . . wiper signal problem

When I turn the stalk to intermittent wipers, the wipers go high speed.
I monitored the parameters in VIDA. The high speed relay is activated.
When I push the stalk down one more click, The wipers remain on high speed and the front washers run continuously
In VIDA, the parameters match what happens.

I tried activating front wipers with VIDA and the front wiper ran at low speed.

I tried changing the wiper relay and high speed relay. No change.

Should I go to the junkyard and get a SWM along with the turn signal & wiper stalk. . . for like $40 and a wiper motor for
around $30.

How do I narrow down exactly what the problem is with the front wipers until I start throwing parts at it?
How do I narrow down the problem with the rear wiper?

ALSO. The rear wiper does not work at all. No sounds from the rear door.

- Don Reiher

[jonesg]

I would try the stalk swap.
or spray it with de-oxit elec cleaner.

[dreiher2]

Thanks! I had to replace both the left turn signal stalk, and the right wiper stalk (one from a salvage yard, one from ebay). All the problems I was having went away. The right turn signal now works and no longer turns on the hi beams, and all the wiper functions now work.

- Don Reiher

[jonesg]

thats a big saving over new parts plus labor. !