How Diagnose Intermittent Wiper Problem?


#1

Car: 95 Olds Cutlass Sierra sedan, 3.1 V-6, just 62K miles (was mother-in-law’s car, now driven by my wife).



Problem: The wipers sometimes will not start working when you turn them on, in any setting (mist, intermittent, slow, fast). Most times they will turn on. My wife thinks that this happens only when turning on the wipers. She doesn’t recall them stopping after they were working.



Question: How do I trouble-shoot this problem? It’s like the old Arkansas Traveler joke: “Farmer, why don’t you cover your house?” “Well, when it’s raining, I can’t, buddy. And when the sun’s shining, it don’t leak!”



In order to diagnose the problem, it has to occur. Most of the time it doesn’t. My wife refuses to drive the car, because if it does rain, and the wipers refuse to work, then she’s stuck somewhere out in the boonies (I can’t argue with this reasoning). So I keep the car at home, taking it out on short errands; the wipers work fine.



A friend suggests the “throw parts at it” approach: “Put in a new wiper motor.” This sounds both inelegant and expensive.



Is there a better way?



PS: Here’s a clue: When the wipers don’t work, the windshield-washer pump doesn’t work, either.



And here’s another: If the wipers won’t start working, they might start working after driving for a while.



Sounds to me like an intermittent open circuit. If it’s in the steering column or the wiper-control stalk, forget it. I’m probably not going to pull off the steering wheel. But taking this to a shop, when it’s so intermittent, seems fruitless.



Any ideas (a) what the problem is? or (b) how to diagnose it?



Suggestions welcome.



PPS: I have a service manual for my now-defunct '89 Olds Cutlass Cierra wagon. As far as I can see, the wiper assembly looks the same as on the '95. Unfortunately, the only trouble-shooting chart is for steady trouble, not occasional.



/Mr Lynn


#2

Bad ground likely between engine and body. Make your own ground wire and try it. Do clean up the contact at the body for the old one. It will cost you some time on your clock but as long as you have time…


#3

If I had to guess I think it is you multifunction switch (wiper switch). Just a guess tho. You need to get a repair manuel on this car that has a wireing schematic and it should show you how to test the multifunction switch (wiper switch) and the wiper motor. That saves at throughing parts at it.


#4

Do you mean between wiper motor and body? Everything else works fine.

/Mr Lynn


#5

I have the '89 manual, which I think is essentially the same car. There is a test diagram for the multifunction switch, which you can test with a voltmeter at the wiper-motor connection.

Problem is, when it’s working there’s no problem to troubleshoot. It only stops working once in a while. And if it’s raining and stops, you can’t work on it!

I will check the connection between the wiper motor and the firewall, as I think pleasedogevan was suggesting above.

What I was really hoping for was a Click-‘n’-Clack moment of revelation, as when Ray says: “I know what it is! Happens to all of them! Just do X”

Anyone?

/Mr Lynn


#6

What I typically do for an obnoxious and very intermittent problem like this is mount a series of lamps or LEDs to a small panel and connect them to strategic points in the problem circuit. The panel gets mounted somewhere out of the way inside the car. When the fault happens, you look at the lamps and can tell immediately if there’s voltage to the necessary parts, and even if there’s voltage where there shouldn’t be.

Takes some work to set it up, and some thinking to pick good places to electrically place the lamps, but it goes a long way towards troubleshooting intermittents.


#7

If the set-up for your wiper motor is the same as on my 1978 Oldsmobile, a lead that is always hot runs to the wiper motor. The switch inside the car completes the path to the ground, For a lower speed, the path goes through a resistor. The intermittent feature goes through a timer mechanism. To see if this is the set-up, use a test lamp and connect one side to a chassis ground or the negative terminal of the battery. Probe the connections on the motor with the switch off and see if on one connection, the test light comes on. If this is the case, then you can check the motor by grounding the other terminal to the chassis. The wipers should come on. If you can catch the wipers not working, follow the above directions. If the wipers then come on, the problem is in the switch or the ground beyond the switch. If the wipers do not come on and there is power to the wiper motor, tap on the motor and see if it starts. I think on your car the wiper motor also drives the pump.


#8

It is most likely the switch on the steering column. It is also most likely that the steering wheel doesn’t need to be removed to replace it.


#9

This problem is almost always the wiper controller/module on a GM car. VERY common problem, It is available at any parts store for about $30. The controller board screws into the back of the wiper motor assembly.


#10

Good suggestions, guys!

I didn’t realize I could just pull out the wiper-wash/turn signal/cruise-control stalk-switch, but after NYBo mentioned you didn’t have to pull off the steering wheel, I looked in the manual. I pulled it out and noticed a break in the insulation on the individual wires in the little bundle that disappears into the column, so conceivably that’s the source of the problem. It was too blinking cold to sit out there fiddling with it this evening, but maybe tomorrow. Jiggling the wires, couldn’t make the wipers stop, so not sure that’s it; might be coincidental. But there’s plenty to try now. Thanks.

/Mr Lynn


#11

I think the advice from TXdealer may be the answer to this problem. If you have any doubts you could check the voltages on the module before the problem happens and then check them again when the trouble occurs and compare the results. For thirty dollars though it might be worth the gamble to just replace it. If you can get into the module and look for bad solder joints try that.