97 Pontiac - wipers stop midway in delay function

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  #1  
Old 06-29-03, 10:19 AM
dishguy
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97 Pontiac - wipers stop midway in delay function

1997 Pontiac Grand Prix SE
Posted this once before without solution but since I had such success with another post on same car, am trying once again.

When you select the delayed wiper action (intermittent setting), the wiper blades have their "pause" portion of cycle directly in line of vision near center of windshield.
The low and high speed wiper actions are normal & wiper comes to rest in proper place when turning off. Peculiar that the various "delay" choices on the control do result in corresponding lengths of delay before the cycle repeats but yet always pause in wrong position. I was thinking if the rheostat in the control was faulty (worn thru wire) that this adjustable rate of delay would not still give the expected variations of delay. IE, if it were bad I would guess that it just wouldn't function at all in delay mode.

Two mechanics have suggested that it actually is the control "switch" assembly in the steering column and so am leaning towards that but since I would like to try to tackle the repair myself, I am a bit hesitant on dealing with the "airbag" issue involved in the steering wheel and working in steering column. I did find at the library, a procedure to disable the air bag but knowing how much misinfomation I have come across, am not 100% comfortable with that.

Wish there was a way to speak/write directly to a GM knowledgeable person that could assure me what the problem must be before delving into the wrong area.
Any other tips appreciated!
Best regards, do
 
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  #2  
Old 06-29-03, 11:04 AM
Joe_F
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If you're not sure with the airbag, don't mess with it. Leave to a pro. SRS disablement must be done correctly.

Beyond that, if you are going to tackle it yourself, this is a job that requires the GM service manual, or at minimum an Alldata.com subscription.

I believe I stated the switch could be bad the last time you posted on this.
 
  #3  
Old 06-29-03, 11:57 AM
dishguy
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I remember that you suggested the wiper "switch" was at fault. I described in my "discussion" however, why I was having trouble being convinced of that.... the mechanic telling me it was the rheostat portion that wears thru.... so thought there could be no harm in asking again in hopes that another person may happen upon this question and know precisely what part of the "switch" fails and how it (electronicly) results in the symptoms displayed.

Guess I will be careful to not ask more than once but thought that other board voluteers / users may see my post that they wouldn't have seen the first time.

May have to "bite the bullet" on this one and take it to a "mechanic" but wanted to try to narrow this down to absolutely the switch in steering column or the "underhood" portion that I would feel better about tearing into.
Again, thanks for your time and assistance.
 
  #4  
Old 06-29-03, 08:29 PM
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GM usually uses what's called a pulse motor on thier wiper systems (the type with variable delays) it's mounted directly on the wiper motor itself. The next time the wipers halt in an incorrect position, give the black plasic cover a LIGHT rap. If the wipers begin to move, that's most likely the culprit. I've replaced 30 of these for every 1 switch assembly.. Usually, there are 3 or 4 torque screws that hold the pulse board in place (t20 I think??) you can unplug the wiring harness connector, remove the screw, and "tug" the board off the motor. (it plugs into the wiper motor with spade terminals.) Flip it over, and chances are you'll burn marks on the circuit board. This is a WHOLE lot easier to remove and check than the switch, and a whole lot more common.
 
  #5  
Old 06-30-03, 06:00 AM
dishguy
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OK... that sounds hopeful for finding a cause that may be a lot easier to solve!

Since I won't be able to get at working on this for a while again, I wanted to make sure I understand what you are telling me.

First, to clarify myself again, when wipers are in any of the delay settings the rate at which they operate corresponds directly with the setting chosen (which is what it should be...).
However, instead of their "pause" portion of cycle being down at the base of windshield, they consistantly "pause" at the same incorrect area of the windshield..... about midway across. Since they are consistant in "where" they incorrectly pause, do you still feel that the "board" could be the cause for this? My experience with bad connections (resulting from a combination of environment effects ---heat,cold,air polutents and vibration) makes it a bit more unpredicatable as to when they "make/break" and so equally random will be the times of the result.

Bottom line..... have you had to replace this "pulse" "timer" "delay" board or is it possible to clean and repair the burnt board area and jumper/splice around the bad connections? Obviously if it is too burnt and includes some "active" components then replacement would be the only option, I suppose.

Again, thanks for the tips and glimmer of hope for a more manageable self fix!
 
  #6  
Old 06-30-03, 08:19 AM
Joe_F
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If the board is wasted, it should be replaced. Most times GM services it separately.

Cars and computers..not always the same with regard to electronics
 
  #7  
Old 06-30-03, 04:35 PM
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If a person can do circuit board repair, then yes usually it can be done. At work, it's not cost effective for the customer or us to do this.
Yes, it is possible to have a totally different problem than the pulse board. But it is something very quick and easy to check, and, in my experience, the most common problem out of the whole system. Why they seem to stop pretty much in the same place is a mystery to me...But yes frequently they do that..
 
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