A/C fan 3rd speed

[LarryMart]

I got my 91 A/C working, except for the evaporator fan speed #3. When 3 is selected, the rad fan engages and runs, but nothing from the back. Reading through the archives, there was a discussion of the A/C relay being the culprit, yet others found it not to be the case. I have not been able to find how to rectify this problem and looking for help.

Thanks,
larry
91 multi

[jlrftype7]

'If', you have 4 speeds, and the lower 3 are through a Resistor to lower the speed, you would need to look for the resistor and test there. It seems like the switch is working since you get a response from the Radiator Fan kicking in for A/C Condenser cooling once you've selected speed 3 on the switch. I don't have my Bentley in front of me, do you have 3 or 4 speeds for the A/C Evap blower?

Found a few threads on this. 4 speed system, Relay for Speed 4, I believe, and two resistors in the A/C cabinet for lower blower speed control [ Westy Rear Cabinet System, and I believe the MultiVan/Passenger Rear Mounted System

https://www.thesamba.com/vw/forum/viewtopic.php?t=757441
_________________
'68 Westy- my first VW and vehicle/Bus- long gone.- sold it to a traveling Swiss couple....
'67 Type 3 Fastback, my 2nd car- gone
'69 Semi-Auto Stick Shift Beetle-gone
2017 MINI Coopers, our current DDs
‘84 Tin Top - Hilga....Auto

[Howesight]

If I recall correctly, both of the two evaporator fans are controlled from the same evaporator fan switch. However, each of those evap fans has its own resistor. If both fans will not run on speed number 3, then that suggests that the problem is the evaporator fan switch, not the resistors.

The fan switch is the easiest part in the system to access, so you may be in luck. If you remove the switch, you can bridge the terminals (look at the wiring diagram first) to see if the switch is at fault. They do fail, so it might be a simple fix.
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'86 Syncro Westy SVX

[crazyvwvanman]

You rectify the problem by replacing the A/C relay that controls fan speed 3.

Mark

[LarryMart]

Thank you for your help!

I do have a 4 speed switch. Is that switch in the dash called the "evaporator fan switch" or ? Ref the A/C relay - I was going to automatically to replace it, as initially it did have a sticky relay in it, plus from all the problems others wrote about. But; I can not locate a relay Is there a substitute relay that can be used, as I did not come across a recommendation within the threads that I found.

Thanks again for your help.

PS. I also can't find a recommended fan relay Meistersatz 7M0-951-253 A / 4H0 951 253 70amp

All leads would be appreciated!
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larry
91 Multivan

[crazyvwvanman]

The A/C relay is the tallest relay in the rear D pillar A/C wiring area.
This relay has multiple functions including evap fan speed 3.

Look at the photo in the first post of the following thread.

https://www.thesamba.com/vw/forum/viewtopic.php?t=757441

Mark

[LarryMart]

Thanks Mark,

I was referring to unable to locate as in to buy a relay, as I haven't found anyone with any in stock.

Thanks again
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larry
91 Multivan

[crazyvwvanman]

It was used in millions of VW vehicles.
Used ones are available.
New aftermarket ones also.


Volkswagen (VW) Cabrio/Cabriolet 1982, 1983, 1989, 1990, 1991
Volkswagen (VW) Cabrio/Cabriolet 1.8L 1992, 1993
Volkswagen (VW) Cabrio/Cabriolet 1.8L K-Jetronic 1984, 1985, 1986, 1987, 1988
Volkswagen (VW) Corrado 1991
Volkswagen (VW) Corrado 1.8L G60 1989, 1990
Volkswagen (VW) Corrado 2.8L 6 Cylinder 1992, 1993, 1994, 1995
Volkswagen (VW) Fox 1990, 1991, 1992, 1993
Volkswagen (VW) Fox 1.8L KE-Jetronic 1987, 1988, 1989
Volkswagen (VW) Golf 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996
Volkswagen (VW) Jetta 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996
Volkswagen (VW) Passat 1991, 1992, 1993, 1994
Volkswagen (VW) Passat 2.0L 1990
Volkswagen (VW) Passat syncro 1991, 1992, 1993
Volkswagen (VW) Quantum 1983, 1984, 1985
Volkswagen (VW) Quantum 1.6L T-Diesel 1982
Volkswagen (VW) Quantum 2.2L KE-Jetronic 5 Cylinder 1986, 1987, 1988
Volkswagen (VW) Quantum syncro 2.2L KE-Jetronic 5 Cylinder 1985, 1986, 1987, 1988
Volkswagen (VW) Scirocco 1982, 1986, 1987
Volkswagen (VW) Scirocco 1.8L K-Jetronic 1983, 1984, 1985
Volkswagen (VW) Scirocco 1.8L KE-Jetronic 1988, 1989
Volkswagen (VW) Vanagon 2.1L 1986, 1987, 1988, 1989, 1990, 1991, 1992
Volkswagen (VW) Vanagon syncro 2.1L 1986, 1987, 1988, 1989, 1990, 1991, 1992

[LarryMart]

Replaced the suggested relay, and #3 evap fan still does not run. As before, 1,2,4 runs..

What to try next?

Thanks,
larry
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larry
91 Multivan

[djkeev]

These A/C units were designed by some demon possessed madman.

Go to this link and read about this fan and the related wiring problems.
You might just consider doing a redesign while you're in A/C mode.......

https://www.thesamba.com/vw/forum/viewtopic.php?t=757441

Dave
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Stop Dead Photo Links how to post photos

Ghia
http://www.thesamba.com/vw/forum/viewtopic.php?t=392473

Vanagon
http://www.thesamba.com/vw/forum/viewtopic.php?p=6315537#6315537

Beetle
https://www.thesamba.com/vw/forum/viewtopic.php?t=482968&highlight=74+super+vert

[crazyvwvanman]

It is a pretty simple area of the wiring.
The fan switch has a single contact for speed 3.
A single wire goes from that switch contact back to the A/C relay speed 3 control pin.

When you switch from speed 2 to speed 3 that relay should click ON.
When you switch back to speed 2 it should click OFF.

Mark