I have a 95 Volvo 850 Turbo Wagon. I've had a very intermittent problem where, when I use my front washers, the wipers and washer pump will not shut off. Sometimes this clears itself in some unknown way, other times it does not. What seems to trigger it is holding the wiper stalk in the washer position for more than a second or so but this happens so infrequently that it is hard to tell.

When this first happened over a year ago I thought that I had diagnosed it down to the wiper controls on the column so I replaced this unit. The problem went away. Then, sometime later, maybe 1-3 months (?) the problem reoccurred, so I then replaced the wiper relay. The problem went away, although at some times the washer would stay on much longer than normal after releasing the stick but it always cleared itself. I seemed to be able to avoid the problem by simply pulsing the washer control as opposed to holding it.

Well now the problem is back and seems "stuck". Any good way to diagnose this? Since I've replaced the other two major components in the system, could this be something to do with the wiper motor? Or wiring?

 

That sound like a tough one, and rare. Usually the wipers will wipe 3 more times when the switch is released. Other than the switch and relay, not sure what it could be.

 

+1

Do the wipers turn on and off normally when you us them in the rain? If so, I am thinking the switch. If it was the relay, they would get stuck on all the time and also, the water pump would stop pumping because that is on a different relay.

 

I looked at the schematic for this circuit for a long time on this one...

There's a "park" switch on wiper motor that, if it were sticking, could cause the wipers to keep running, but not the washer motor too. The only way that could happen is if the park switch was bad in one of the headlight wiper motors AND a diode in there was shorted too; pretty unlikely...

So here's what I'm thinking; it's the switch, again.

Why? I am thinking the washer motor (and/or one/both of the headlight wiper motors) is drawing excessive current, which is melting the contacts on your wiper switch. Ck fuse 34; supposed to be 25A; make sure someone didn't put a bigger fuse in there.

BTW: If I can believe the schematic, the current for all 3 motors (washer and 2 headlight wipers) runs through that switch w/o a relay! Poor design IMO. Hard to believe that switch can handle 25 amps...

I would pull the fuse 34, insert an ammeter on 10 amp scale. Unplug all 3 motors (washer and 2 HL wiper). Activate the washer switch and note the current draw. Then, one at a time, plug in the washer/HL wiper motors, again activate the switch, and note the current draw. My guess is one of them will be excessive.

 

Gdog,

I'm back on this board after not having visited since I posted this issue. I wanted to let you know that it was indeed a problem with one of the headlight wiper motors. My mechanic at the time said that it was not all that uncommon in Saabs and also Volvos.

So very good diagnosing on your end.