Fast Wipers only, no washer spray

[Panama Red]

Hi everybody!
New to me Rainier owner here. I have searched the forums, and I think I have an idea, but I would like a little verification.

My front wipers will only run at fast speed, all other switch positions return the wipers to rest. Also no washer action.
I have verified that the washer pump works. If I leave the switch on one of the other speeds, occasionally they will turn on then quit shortly thereafter. I thought about the pulse board circuit, or the multifunction switch{MFS}, but after reading posts, and studying wiring diagrams, I found that there are two rotary contact switches in the MFS that one failure could cause all my symptoms.

So. Is the MFS my most likely culprit?

Thanks!
TJ - Panama RED

2005 BuicK Ranier CXL AWD 4.2L 150K miles approx.

 

[TJBaker57]

Hi everybody!
New to me Rainier owner here. I have searched the forums, and I think I have an idea, but I would like a little verification.

My front wipers will only run at fast speed, all other switch positions return the wipers to rest. Also no washer action.
I have verified that the washer pump works. If I leave the switch on one of the other speeds, occasionally they will turn on then quit shortly thereafter. I thought about the pulse board circuit, or the multifunction switch{MFS}, but after reading posts, and studying wiring diagrams, I found that there are two rotary contact switches in the MFS that one failure could cause all my symptoms.

So. Is the MFS my most likely culprit?

Thanks!
TJ - Panama RED

2005 BuicK Ranier CXL AWD 4.2L 150K miles approx.

In testing I tend to go to the low hanging fruit first.

By removing a few lower dash/steering column panels/covers you can access C201.

There you could test the funtioning of the multi-function switch as it pertains to the front wiper system.

I would first check for the low voltage power supply to the switch and if that tests good then test the return signal back to the wiper motor/control board.

C201 — 2005 Buick Rainier AWD L6-4.2L VIN S Service Manual | Operation CHARM

Detailed repair manual for the 2005 Buick Rainier AWD L6-4.2L VIN S.

charm.li

Electrical Diagrams — 2005 Buick Rainier AWD L6-4.2L VIN S Service Manual | Operation CHARM

Detailed repair manual for the 2005 Buick Rainier AWD L6-4.2L VIN S.

charm.li

While everything is connected you cannot read the resistances through the switch but given the resistances we can compute what each operational mode voltage return signal should be.

That said it is not really necessary in your issue to know the various voltages, it will be enough to know if the supply voltage is there and that varying voltages are present at the return signal wire.

 

[Panama Red]

In testing I tend to go to the low hanging fruit first.

By removing a few lower dash/steering column panels/covers you can access C201.

There you could test the funtioning of the multi-function switch as it pertains to the front wiper system.

I would first check for the low voltage power supply to the switch and if that tests good then test the return signal back to the wiper motor/control board.

View attachment 114749

C201 — 2005 Buick Rainier AWD L6-4.2L VIN S Service Manual | Operation CHARM

Detailed repair manual for the 2005 Buick Rainier AWD L6-4.2L VIN S.

charm.li

Electrical Diagrams — 2005 Buick Rainier AWD L6-4.2L VIN S Service Manual | Operation CHARM

Detailed repair manual for the 2005 Buick Rainier AWD L6-4.2L VIN S.

charm.li

While everything is connected you cannot read the resistances through the switch but given the resistances we can compute what each operational mode voltage return signal should be.

That said it is not really necessary in your issue to know the various voltages, it will be enough to know if the supply voltage is there and that varying voltages are present at the return signal wire.

Thanks, I'll check that out!