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Wipers work on high speed only

10K views 19 replies 8 participants last post by  Dlwoa's 
#1 ·
1997 Safari, wiper work on high speed only......I know the pulse boards can cause issues but not sure about the combination switch either. Can anyone provide a schematic so I can diagnose it properly and not guess. I used to work at GM but no longer have access to Service Info anymore. Thanks in advance,
 
#5 ·
Here is a wiring diagram of the wiper circuit,,I'd have to dig for the schematic of the board,
I just did the soldering of the board on mine today , will install when the rain stops . Mine seems to be more temperature sensitive , last fall and winter when the temps dropped it would start working then just stop in the middle of the windshield , or when starting it would slowly drag the wiper a few inches then stop ,when the spring came with warm temps , never had a problem all spring or summer , but lately early in morning with cool temps and moisture on the van it started doing the same as last year. So I pulled the board and inspected it ,,did not see any noticeable solder cracks on board , just added some solder on known problem areas , hopefully that helps ,
 

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#6 ·
Thank you for providing a wiring diagram. My recently acquired 97 Safari had working washer and wipers when I got it a few weeks ago, and now they don't. I replaced the board with one from a junkyard car (no change) and I re-soldered the solders for the pin connector (no change). I have checked the fuse #11 and it is OK.

I will use the wiring diagram to try and see if power is getting to the plug that plugs into the wiper assembly.

I saw reference to a diagnostic procedure for the switch, wiper, etc. Is that posted somewhere, or is it only in the service manual...?

thanks
Scott
 
#7 ·
The wiring diagram was helpful but didn't solve my problems. I have two boards, the original and a junkyard board. The 5 solders on the original have been re-soldered.

Using board one:
key in off possition:
Black wire is ground, as it should be, yellow wire not hot.
key in ACC position
Black wire is not grounded (?), yellow wire is hot, as it should be.
None of the multi-function switch funcionality works.

If I add an external ground wire to the casing of the assembly, everything works correctly while key is in ACC position.

Using board two:
key in off possition:
Black wire is ground, as it should be, yellow wire not hot.
key in ACC position
Black wire is still grounded, yellow wire is hot, as it should be.
None of the multi-function switch funcionality works.

If I add an external ground wire to the casing of the assembly, everything works correctly while key is in the ACC position except for the Washer function.

My conclusion is that both boards are messed up in different ways and that my choices are to buy a new board or add the external ground wire as a more permanent solution.

Does anyone know why GM went to such trouble to isolate the unit from ground???

thanks
 
#8 ·
scoot said:
The wiring diagram was helpful but didn't solve my problems. I have two boards, the original and a junkyard board. The 5 solders on the original have been re-soldered.

Using board one:
key in off possition:
Black wire is ground, as it should be, yellow wire not hot.
key in ACC position
Black wire is not grounded (?), yellow wire is hot, as it should be.
None of the multi-function switch funcionality works.

If I add an external ground wire to the casing of the assembly, everything works correctly while key is in ACC position.

Using board two:
key in off possition:
Black wire is ground, as it should be, yellow wire not hot.
key in ACC position
Black wire is still grounded, yellow wire is hot, as it should be.
None of the multi-function switch funcionality works.

If I add an external ground wire to the casing of the assembly, everything works correctly while key is in the ACC position except for the Washer function.

My conclusion is that both boards are messed up in different ways and that my choices are to buy a new board or add the external ground wire as a more permanent solution.

Does anyone know why GM went to such trouble to isolate the unit from ground???

thanks
IF
scoot said:
None of the multi-function switch funcionality works.
You may have more problems ,, the cruise control is part of that circuit and the turn signals , di you check the fuse for the cruise control ?
Do you get the same test result when key is on or in the run position?
 
#11 ·
Phantom said:
You can run test jumper wires directly from battery to wiper motor to see if that shows the motor to work , , there are connectors to the washer pump you can test with a meter to see if voltage is getting to the washer pump
Both wiper motor and washer motor work if I add a ground wire to the wiper casing. I bought a new board at NAPA that I will install in the morning, hopefully that will allow me to remove my improper ground wire.
 
#12 ·
UGGGGGGG !!!! New board does _exactly_ what existing board does. Everything works if I add a separate ground wire to the board housing, nothing works if I don't. (and cruise control does work regardless). Why...... ?????? GM clearly went to lengths to insulate the housing from the car rather than have it ground directly...
 
#14 ·
Phantom said:
The wiper motor has a black wire that connects directly to chassis ground .

The washer pump has a black wire that goes to chassis ground at a different location

Go to the chassis ground locations and remove the ground wire and clean the connections at both places , then test for continuity .
Let's ignore the washer for a moment. The wiper motor does have a black wire, the center pin in the set of 5 pins in the plug harness. The wiper moter and board assembly are explicitly isolated from ground in the manner that they are installed. Unlike everything else on the firewall, they appear to be isolated with rubber grommets or something. Or maybe that is just for making things less rigid.

Anyway, I'm assuming the ground wire is the center pin black wire of the connector. Are you saying that there is an additional ground wire? If so, where does it connect to the wiper motor or board assembly?

My current situation is that the black wire, center pin, and wiper board/housing are all grounded if the key is in the off position, and that they are all NOT grounded if I move the key to the accessory position. Is this consistent with a bad ground? Perhaps. If so, where do I find

"S206" (1997-1999) "Left side of firewall above battery" and "G104" (1996-1997) "Left side front of dash above battery" ? I understand (I think) where the firewall ground is, but I have no idea where they want me to look for "left side front of dash above battery". Is there a picture that shows a map of "S206", "G104", etc?

thanks
Scott
 
#15 ·
scoot said:
"S206" (1997-1999) "Left side of firewall above battery" and "G104" (1996-1997) "Left side front of dash above battery" ? I understand (I think) where the firewall ground is, but I have no idea where they want me to look for "left side front of dash above battery". Is there a picture that shows a map of "S206", "G104", etc?

thanks
Scott
The ground is very easy to see when you raise the hood , it is a stud with a nut on it that has a black wire attached to it...only a small portion is seen easily , the wire goes down and into a harness that goes to the wiper motor

Try running a wire from the black wire on the wiper motor plug to the ground stud above the battery and see it wiper works then .
 

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#16 ·
Phantom said:
The ground is very easy to see when you raise the hood , it is a stud with a nut on it that has a black wire attached to it...only a small portion is seen easily , the wire goes down and into a harness that goes to the wiper motor
The wiring diagram shows "S206" and "G104". Do I need to find two points? In any case, I have the picture of what I think is the same ground point on my van (see below)
WiperGround1.jpg


And if I add this little green ground wire everything works, but why are there rubber buffers? (see below)

WiperGround2.jpg

sorry I got the attachments goofy.
 
#18 ·
Grommet are to minimize the vibration caused by the wiper motor and mechanism that make noise , that vibration would resonate into the interior of van ,
wiper blades that are not wet make a lot a noise themselves :lol:
Yea the green wire hook there should be fine , you may have a dirty connection or broken wire at that ground location

Not sure right off what that red wire is for , I would test to see if it has voltage with key on and off , it may be for an option your van does not currently have
 
#19 ·
So...Just learned a lot from this posting, but whave a slightly different problem....99 astro. So you said the yellow wire is hot? MIne is not. The other three are. Red is hot all the time, and the other two shift in voltage as a I move the switch between speeds...

My problem is wipers and washer pump just stopped working...zilch. Luckily it would seem the switch works. but i would still like to clarify the role of the yellow wire and why it shows zero voltage when I measure it with the hot wire on my meter and the negative meter wire onto the center black ground wire. Any ideas what might be going on here?

Thanks.
 
#20 ·
I have an 04 Astro that I had similar problem on. ( caused by being lazy and using wiper motor for ground during jump start!) I had another circuit board inside the wiper motor that had an open trace. Solder jumped it and I no longer needed the additional ground wire. The new pulse board didn't fix the intermittent wipers though. I only have 2 speeds, low and high. I figure I fried something further down the line but don't have access to a schematic to find out what got cooked.
 
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