weird windshield washer problem (c900)

Hi,

I'm experiencing a very weird problem with my 1992 900s. I drove a few hundred miles this weekend, and the car functioned perfectly in every respect. I especially enjoyed using my newly repaired cruise control. I parked the car as usual last night, and went to bed a happy Saab owner.

This morning, when I started the car, the windshield washer started spraying immediately, wipers going, and headlamp wipers/washers going. Very strange. I fixed the problem temporarily by pulling fuse #8, which is labeled "headlamp wipers," and appears to also govern cruise control and the power side mirrors.

So, my question: what could cause the wipers/washers to behave this way? I might blame the switch, although it was replaced only a year or two ago. I'm a little worried that my cruise control repair is somehow involved, since the two things are on the same fuse.

Any ideas?

Thanks,

John

Reply to
John B
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You could try to disconnect the headlamp wipers, just to be sure you don't have a problem in one of the headlamp wipermotors. There are a 3 terminal connector about 20 cm from each motor that you could pull to test.

/Mats

Reply to
Mats

Thanks, I will try that. I have a hard time imagining, though, how a problem with the headlight wipers could somehow feed back to the intermittent relay, thus activating the windshield wipers and washer pump. And yet it seems like that's what is happening.

John

Reply to
John B

Hi John,

The same thing happen to me about two years ago except I was in the middle of traffic. I pulled the fuse then found that when I disconnected one of the headlight wipers things were OK. When I looked up the circuit diagram for the car (a 94 9000CSE) I figured that it had to be a shorted diode but when I took the wiper motor apart there was no visable diode. As it turns out, the diode is embedded in a rubber like plug of stuff on the edge of the motor housing and one does not have to disassemble the wiper motor. There are probably diodes for the main motors as well so it could be one of them. The purpose of the diodes is to allow the wipers to return to their resting position after the power to them is shut off. There are internal switches in the motors that get there power through the diodes. If anu diode shorts out it sends power to the all the motors and the washer pump.

The alternative is to simply replace the whole motor assembly. They come up on Ebay all the time.

Good luck, R. Frist

Reply to
R. Frist

This solution is the only one that makes sense, although there are some weird arrangements. Is it possible that the manually operated switch is so constructed that it can fail to a condition that it can "Transfer" power from one circuit to another (continuous or intermittent) but not "Interrupt" the power to both?

I still like the diodes, however.

Malcolm Mason

Reply to
Malcolm William Mason

Thanks for the replies. I finally had a chance to check things out today. First, I tried unplugging both wiper motors. This resulted in the problem going away. So then I tried having each plugged in, one at a time. Still no problem. So finally I plugged them both back in, and the problem still failed to manifest itself.

So it seems as though unplugging and re-plugging the motors has solved the problem. However: the left side motor doesn't seem to be working. The plastic panel on the back of the motor isn't totally attached, and the wiper moves freely when the motor is off.

So I'm thinking I might want to replace that motor. It looks like I'll have to pop the headlight assembly out to do it. Will it be necessaary to re-aim the headlight after this? This is a 1992 900 (slant-front headlights).

John

Reply to
John B

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