Cooling fan testing

[Monkeymagic]

I was sat stationary for a while today and noticed the temp guage had crept right up and i hadn't heard the fan kick in. After switching the engine off i could hear the after-run pump! I have never heard the after run pump in my ownership. I realise it does not kick in until 110c.
I have disconnected the plug from the thermal switch and bridged the two outer contacts and the fan kicked in on what i believe was hi speed.
Despite any other configuration i could not get the fan to kick in.
With the jumper wire in the red/green and the centre contact i could hear a faint click in from in the car.
Im sorry i couldn't really see the wire colours as it was dark. I belive the green/red is the 12v feed., I have to admit my auto electrics aren't the best.

Am i right in thinking the low speed fan circuit is dodgy somewhere? That said if the after run pump had kicked in then the hi speed fan should have kicked in first shouldnt it.

My understanding is low speed fan kicks in at 95
the hi speed at 102
After rn pump at 110.

The only thing i can think has changed was i changed the mfts for a genuine one as my old one was setting the coolant warning off on occasion.

[twoqu]

Mfts has nothing to do with cooling whatsoever!
This of any use?

http://www.s2forum.com/forum/showthread.php?t=59802

[Mikes2]

There are 3 speeds

Speed 1 : if your car has air-con, it will run this all the time if the air-con is switched on and the outside temp is above 5 degrees C. This is also the after run speed which is triggered by the 2 pin sensor on the water rail

Speed 2 : normal fan speed for engine cooling. triggered by the thermoswitch in the radiator

Speed 3 : high speed fan for extra cooling when the water temperature gets too high for speed 2 to cool. this is also triggered by the thermoswitch in the rad

[twoqu]

Sounds like the 2nd stage relay is faulty.

[Monkeymagic]

I have just been out in the car and left it to run. the temp gauge was dead centre between 90 and 120 and the fan kicks in for a few seconds then off again maybe three times then on the fourth kicked in for about 8-10 seconds then off agaiin as it always has.
Weirdly though I have never seen the gauge go that high before, that said since i swapped the mfts the gauge reads anotch or two higher than previously anyway.
Am i worrying about nothing?
Only odd thing is as I have bridged the thermo switch terminals shouldnt i be getting two speeds as i bridge the two outer terminals and then the outer and middle terminal.?

[Monkeymagic]

PS I dont have a/c.

[Monkeymagic]

When my after run pump was pumping away the fan was not active. Also when the temp gauge was 2 notches above 90 i thought i heard a faint click from a relay. The problem is i guess is that I need to determine wether the fan i do get is stage lo or hi. It kicks in with some speed but only for a short while.
Im beginning to think the fact I only get one speed when bridging the wiring terminals would suggest the lo speed relay is at fault.

[UrS4boy]

After-run pump and fan and thermostat info

When my after run pump was pumping away the fan was not active. Also when the temp gauge was 2 notches above 90 i thought i heard a faint click from a relay. The problem is i guess is that I need to determine wether the fan i do get is stage lo or hi. It kicks in with some speed but only for a short while.
Im beginning to think the fact I only get one speed when bridging the wiring terminals would suggest the lo speed relay is at fault.

I can offer these:

After-run pump and control module info:

http://forums.quattroworld.com/s4s6/msgs/21503.phtml

Thermostat info:

http://forums.quattroworld.com/s4s6/msgs/21881.phtml

Rad Fan wiring pgs. 16/17 and 17/17 of this pdf:

http://www.s2central.net/S2_Schematics/A/A17.PDF

After-run pump (and Stage 1) fan schematic:



Annotated Watertemp gauge:

[Monkeymagic]

Ok so its fair to assume my lo speed is not kicking in then. Only problem is wiring schematics may as well be in chinese. Where is the relay on a 3B? Ill get a new one ordered. Many thanks Steven

[UrS4boy]

Ok so its fair to assume my lo speed is not kicking in then. Only problem is wiring schematics may as well be in chinese. Where is the relay on a 3B? Ill get a new one ordered. Many thanks Steven

Since you replied I added a link to some 3B wiring pdf info. Check it out.

The location of the 3B relays in question and the 324 control module are shown in my after-run pump post, linked above, and again here (you need to read it - ALL ):

http://forums.quattroworld.com/s4s6/msgs/21503.phtml

[Monkeymagic]

The problem I have is that vehicle electrics and trying to read that ,my brain just tunes out. I was the same with maths at school. Maybe its time to find an auto spark. Thank you for the help. Steven.

[Error404]

To test the after-run fan speed, just bridge the two spades that go to the after-run pump switch on the water rail.

To test the 2nd and 3rd stage speeds on the 3B, bridge the terminals at the temp switch on the rad.

Bridge pin 2 to pin 3 to trigger the 2nd stage fan.
Bridge pin 3 to pin 1 to trigger the 3rd stage

HTH mate

[Fat Audi 80]

The new 2 pin MFTS will read two notches higher. This is not an accurate temperature measurement any more. If your fan is kicking in on speed 2 for 10 - 20 seconds then your cooling system is working normally.

P.S. mine is the same...

HTH

[Monkeymagic]

Alex do you mean bridge terminal 1 to 1?
when you bridge the after run contacts should the fan come on with the pump?
my fan kicks in but for less than 10 seconds

[UrS4boy]

Bridge pin 1 to pin 1 to trigger the 3rd stage

Hmm....seems perverted?