Home Technical Discussions Volkswagen Passat: 1995-1997 (B4)

Volkswagen Passat: 1995-1997 (B4) Location of 3rd speed coolant fan control switch thermal switch?


Permlink Replies: 40 - Pages: 3 [ 1 2 3 | Next ]
Last Post: Apr 2, 2014 2:32 PM Last Post By: bill4
Gus G

Posts: 31
Registered: 10/04/04
Location of 3rd speed coolant fan control switch thermal switch?
Posted: Oct 7, 2005 5:49 PM
  Click to reply to this thread Reply
Does anyone know where the location of the 3rd speed coolant fan control switch thermal switch? It is identified as F165 on sheet 21/2 of the Bentley wiring diagram. I cannot locate this switch in the bentley book.
Gus G

Posts: 31
Registered: 10/04/04
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Oct 11, 2005 10:18 PM   in response to: Gus G in response to: Gus G
  Click to reply to this thread Reply
It's okay no one needs to reply, I figured it on my own.
wohlfarth

Posts: 1,744
Registered: 10/31/03
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Oct 12, 2005 9:50 AM   in response to: Gus G in response to: Gus G
  Click to reply to this thread Reply
Can you let us know where it was located and any more detail that might help someone else down the road?

thanks,

Stan
Gus G

Posts: 31
Registered: 10/04/04
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Oct 12, 2005 12:15 PM   in response to: wohlfarth in response to: wohlfarth
  Click to reply to this thread Reply
The correct name for this sensor is the "A/C Cut-out Thermal switch/3rd Speed coolant fan switch". It is the brown sensor located in the thermostat housing underneath the coilpack. It is visible from the front of the engine beside 2 other similiar sensors.

Basically, when I would turn my ignition switch to position 2 or start the car, the 3rd speed fan would kick-in immediately and remain running until I turn-off the car. Just had to replace the sensor.

Unplug the connector, remove the Uclip around the sensor with a screwdriver and pull-out the sensor. Also get a new seal for it while you are there. You will lose coolant so you can plug the hole temporarily while you are replacing the sensor or just swap the parts as fast as you can. Either way you will have to add whatever coolant you lost back into the coolant reservoir.
wohlfarth

Posts: 1,744
Registered: 10/31/03
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Oct 12, 2005 12:25 PM   in response to: Gus G in response to: Gus G
  Click to reply to this thread Reply
Now that's what I'm talking about! Glad you could figure it out and thanks a lot for putting words to the solution. Hopefully it will help someone else out in the future.

I'll be taking a look at my own '95 Passat tonight for that sensor. Right now I have my starter out getting it repaired at a local starter/alternator shop. The braided connector wire between the solenoid and starter was all cruddy and broken.

thanks,

Stan
meyerhd

Posts: 10
Registered: 03/30/05
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Nov 3, 2005 12:31 PM   in response to: wohlfarth in response to: wohlfarth
  Click to reply to this thread Reply
Removed
jahulobo

Posts: 2
Registered: 08/29/10
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Aug 29, 2010 1:39 PM   in response to: Gus G in response to: Gus G
  Click to reply to this thread Reply
Thank you, thank you, thank you!!! Your post was invaluable! I can't believe how long I have searched for this information. If everyone on every forum could just quickly follow up their findings the way you did there would be far less chatter and faster and easier repairs being made to our vehicles.

Thanks again! You are my hero! :)
bill4

Posts: 31
Registered: 10/30/11
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Nov 5, 2011 11:18 PM   in response to: jahulobo in response to: jahulobo
  Click to reply to this thread Reply
So what are the other 2 sensors for???
Just wondering as my cooling fan only runs when I turn the car off.
Also how do you know if it is 2 speed or 3 speed??

Edited by: bill4 on Nov 5, 2011 11:19 PM
FKH161

Posts: 7,594
Registered: 12/29/05
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Nov 7, 2011 8:18 PM   in response to: bill4 in response to: bill4
  Click to reply to this thread Reply
Attached is a wiring diagram.

How many wires are on the radiator harness plug?

Speed one & two are controlled by the rad fan switch on the side of the radiator (battery side).

The brown temp switch in the thermostat housing is the a/c cut-out switch.

The yellow sensor is for the dash gauge & coolant after-run pump.

The blue sensor is for the ECM.

Make sure fuse #19 in the car is ok.

There are some fuses on the coolant fan control module (black brick next to coolant reservoir), make sure those fuses are also ok.
bill4

Posts: 31
Registered: 10/30/11
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Nov 7, 2011 10:08 PM   in response to: FKH161 in response to: FKH161
  Click to reply to this thread Reply
3 wires on rad harness plug
fuse 19 ok
fuse 30 on coolant fan control moduel ok
FKH161

Posts: 7,594
Registered: 12/29/05
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Nov 7, 2011 10:27 PM   in response to: bill4 in response to: bill4
  Click to reply to this thread Reply
If the radiator fan only has 3 wires, then it's a two speed fan.

Did you mean the rad fan thermo switch has three wires?
bill4

Posts: 31
Registered: 10/30/11
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Nov 7, 2011 10:41 PM   in response to: FKH161 in response to: FKH161
  Click to reply to this thread Reply
The fan motor has 4 wires
The sensor on the side of the rad has 3
Is there any way to test the cooling fan control module
FKH161

Posts: 7,594
Registered: 12/29/05
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Nov 7, 2011 10:47 PM   in response to: bill4 in response to: bill4
  Click to reply to this thread Reply
On the thermo switch plug of the radiator, bridge the hot wire with one of the other two... see if the fan spins.

Is the engine actually overheating or is it just that you always hear the fans run after shut down?
bill4

Posts: 31
Registered: 10/30/11
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Nov 7, 2011 11:05 PM   in response to: FKH161 in response to: FKH161
  Click to reply to this thread Reply
Engine overheats and no fan untill engine turned off
Fan runs when wires jumped
FKH161

Posts: 7,594
Registered: 12/29/05
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Nov 7, 2011 11:10 PM   in response to: bill4 in response to: bill4
  Click to reply to this thread Reply
If the thermostat is not opening, then the switch in the radiator will not trigger the fan.

Or

If the thermo switch is not working, then the fans won't come on.

My guess is faulty thermostat.
bill4

Posts: 31
Registered: 10/30/11
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Nov 7, 2011 11:10 PM   in response to: bill4 in response to: bill4
  Click to reply to this thread Reply
Fan only runs when I jumped 2 wires
I jumped power to one wire it ran then jumped power to the other wire it did not run
FKH161

Posts: 7,594
Registered: 12/29/05
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Nov 7, 2011 11:21 PM   in response to: FKH161 in response to: FKH161
  Click to reply to this thread Reply
Don't worry about not running off of the other wire... for now.

From a cold start, monitor the radiator temp by touching the core with your fingers from top to bottom. You might have to poke through between the rad fan blades ... so be careful.

Even if the thermo switch only works on one speed, it should still keep the engine temp low enough to keep it from overheating... as long as the thermostat is opening correctly.
bill4

Posts: 31
Registered: 10/30/11
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Nov 7, 2011 11:29 PM   in response to: FKH161 in response to: FKH161
  Click to reply to this thread Reply
ok will try this tommorow night.
Think I will change the thermostat anyhow I have heard that they cause problems in these cars.
I will run the temp in rad test first and watch my fingers.
will let you know how it turns out.
FKH161

Posts: 7,594
Registered: 12/29/05
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Nov 7, 2011 11:33 PM   in response to: bill4 in response to: bill4
  Click to reply to this thread Reply
Don't forget to reattach the rad fan thermo switch... better yet, once it starts to get warm, bridge the wires that cause the fans to run. See if it still overheats then.

Good luck.
bill4

Posts: 31
Registered: 10/30/11
Re: Location of 3rd speed coolant fan control switch thermal switch?
Posted: Nov 7, 2011 11:36 PM   in response to: FKH161 in response to: FKH161
  Click to reply to this thread Reply
OK will do this before i change thermostat

Point your RSS reader here for a feed of the latest messages in all forums

Popular Discussions:
No popular dicussions.