AAN 'mfts' sensor query

[brizer]

Hello folks..

Currently own a SWB replica with an AAN engine conversion. I bought as a 99% finished car, so i have almost all the wee problems sorted.

However i am trying to get the cooling fan working, and have read about the multi function temp sensor. The problem is that there are no wires connected to this sensor on my engine, and i cannot find a plug / wires around the engine bay which fits the 3 pin mfts socket.

Can anyone help me identifying which colour wires goes to this mfts sensor ?? If i knew this then i will have another look to find these wires....

Cheers Brian

[irishs2]

You might find what you need here

http://forums.quattroworld.com/s4s6/msgs/22584.phtml

[brizer]

Thank you Eric...

Do you know which sensor kicks the fan on when engine temp gets too hot ??

Not high up on the electrical side of things......

Cheers again

[irishs2]

I think the fan is controlled by the thermo-switch in the rad itself.

This might help

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

[brizer]

Ah ok... In the water rail beside the mfts sensor there is another wee sensor - the smallest one in the pic below... Does anyone know what its function is ....

[irishs2]

It looks like the one for the coolant pump..
Pointed out here : http://forums.quattroworld.com/s4s6/msgs/22584.phtml

[UrS4boy]

It looks like the one for the coolant pump..
Pointed out here : http://forums.quattroworld.com/s4s6/msgs/22584.phtml

Brizer/Brian: Just got up (7:30 AM here in Vancouver BC). Got your message but decided to check the forum postings first. Saw your thread. I was very pleased to see that IrishS2 has been pointing you to the resources I created for everyone to use. (Thanks Eric, had I known, I would have slept in for another 30 min. )

Anyway, to do my bit, the direct link to the after-run coolant pump switch is here:

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

It triggers a brown relay (324) that used to live in one of the kick front panels on the UrS4/S6s (e.g., right hand on the LHD cars). In turn, the 324 triggers a 214 relay in the lunch box relay panel under the bonnet. That 214, along with another 214 in the same panel, controls power to the fan (once energized by the rad temp switch, etc). http://forums.quattroworld.com/s4s6/msgs/152019.phtml

That said, as others pointed out, there is a switch on the AAN rad that feeds back to that 214 relay and would bring the fan on while the engine is running if the temps were high enough. The Automatic A/C system would also trigger this fan coming on.

You might have to rig up a manual switch and a 214 relay to control the fan if you don't have all of the C4 UrS harnesses.

[brizer]

I for some funny reason think the previous owner has done away with the after run coolant / pump setup when he built the car. No doubt it probably isn't a good idea to run without it so may look about buying one for it.

The reason i say this is because there is a temp switch, part 049 919 501b (small sensor pictured above) screwed in where the after run pump temp sensor should be. So obviously this temp switch is for turning fan on/off. Plus i can't find the after run / electric pump setup.....

Can anyone please advise anymore on this ......


Cheers

[UrS4boy]

I for some funny reason think the previous owner has done away with the after run coolant / pump setup when he built the car. No doubt it probably isn't a good idea to run without it so may look about buying one for it.
The reason i say this is because there is a temp switch, part 049 919 501b (small sensor pictured above) screwed in where the after run pump temp sensor should be. So obviously this temp switch is for turning fan on/off. Plus i can't find the after run / electric pump setup.....Can anyone please advise anymore on this ......
Cheers

I guess you haven't had time to check the link to the after-run coolant pump that I posted above: http://forums.quattroworld.com/s4s6/msgs/21503.phtml

As you will read, that pump is only triggered to come on when the engine is off and the coolant temp rises to 110 C. Once the switch (PN 054919369B) is triggered (the two wires to it are "hot" all the time), the 324 timing relay runs the pump and the fan for 10 minutes. If the coolant was still over 97C, then the cycle would repeat, as needed. The 054919369B closes at 110C and opens at 97C (or cooler).

For a purpose-built car like yours, you could have a manual switch to do this.

049919501B is an older switch, e.g. from a 1987 KV 10v. It has an activation temperature of 120 C, not 110C like the 054919369B. Both are 2 pin and both have M10x1 threads. 120C is too hot for the 20VT after-run pump circuit. Replace with the 054919369B.

[brizer]

Read through all there now sir... Not big up on the electrical side of things in fairness.

Thanks Dave............

[macspring]

I guess you haven't had time to check the link to the after-run coolant pump that I posted above

Dave, you have to remember to remain cool, calm, and collected when dealing with mere mortals such as myself, and Brizer etc.

If you don't you'll harm your karma, and blow a core plug.

Not everyone appreciates your logical / methodically approach.

Kind regards.

[UrS4boy]

Dave, you have to remember to remain cool, calm, and collected when dealing with mere mortals such as myself, and Brizer etc.

I am in the middle of doing a C4 heater core using the DIY *I* wrote so I am a little less patient than I need to be. (The new DIY will be "new and improved" with more photos and hints) Duh.