water temp gauge reading up and down.

[K7ERG]

Over the last few weeks I have noticed the temp gauge going up to 90ish but drops off down to near cold. This can happen during running so should be relatively constant and on idle stuck in traffic.

I am wondering if it is a dodgy thermostat or coolant temp sensor.

[spink]

either stat or mtfs.coolant temp sensor isnt used for any gauges.mtfs is same as any 20vt one,but if your connector has only 3 pins you must only fit a 3 pin mtfs.4 pin wont work

[K7ERG]

Will have a look today. Fitting new discs and pads on the front. Should have one kicking about somewhere.

[johne]

I think you need a new thermostat.

John

[UrS4boy]

MFTS and Thermostat info

Because it goes up and down, it is most likely the MFTS. Have a read on this:

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

[K7ERG]

Thanks for the info. I think its the switch. If this is not working right will it have any affect on performance. It is the 2.5tdi 5cyl engine code AEL.

it is the 3 pin version.

could someone find a part no for it?

[spink]

Thanks for the info. I think its the switch. If this is not working right will it have any affect on performance. It is the 2.5tdi 5cyl engine code AEL.

it is the 3 pin version.

could someone find a part no for it?

doesnt have any affect on performance on these(on mine it doesn't at least),the other day my gauge was reading 50'c max had a look and one wire to the mfts had snapped off and the connectors were rotting away.Spliced in a new connector a few inches down as the actual wiring was starting to go brittle aswell, still wasn't reading more than 50'c so put another mfts on and it is now fine.

Incidently the broken wire to my mfts was causing the coolant level sensor wiring in the expansion tank to only output 0.3v instead of 12v,I have had the warning on the dash for several weeks but hadn't had chance to investigate(I knew the level sensor was ok)

[K7ERG]

Will check wiring but think I will change the sensor

[veneto rs2]

never had this problem on the RS2 but....
On the Cabriolet the same issue that you have was caused by the screws that are connecting the gauge to the instrument cluster I change the washers of those screws with the "toothed" ones and a little bit of very fine sand paper on the cluster contacts where the washers are sitting and tip top the aguge started to work back again (in all honesty I had both gauges petrol+water not working properly) before this I tried the thermostat the sensor the all lot but those connections where the problem.

I remember that on S2/RS2 there should be bolts instead of screws but it could worth a try?

Stefano

[RS2]

I'm in the middle of wiring up my AAN into a VW Transporter Syncro.

Which of the coloured plugs do the Brown/Yellow wire (pin T), Black/Blue (pin +) and Blue/Yellow (pin C) go to so I can wire them in?

I'm guessing as I don't have the mirror control module, my MFTS currently won't be getting a feed?

MG

[UrS4boy]

I'm in the middle of wiring up my AAN into a VW Transporter Syncro. Which of the coloured plugs do the Brown/Yellow wire (pin T), Black/Blue (pin +) and Blue/Yellow (pin C) go to so I can wire them in? I'm guessing as I don't have the mirror control module, my MFTS currently won't be getting a feed? MG

Don't know if you saw this chart (below) or not (from my MFTS post (with diagrams)):

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

[RS2]

I have that table printed out.

It doesn't list which connectors the wires go to.

From what I can see, as my engine is a 1996, it may have a 3 pin sensor. Will check later on.

MG

[UrS4boy]

I have that table printed out. It doesn't list which connectors the wires go to. From what I can see, as my engine is a 1996, it may have a 3 pin sensor. Will check later on. MG

You will have the 3 pin MFTS most likely. Have you not gone to the link I keep pointing to and the diagrams that show which colour wire goes where?

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

[RS2]

Hi, yes and I've saved the table as I stated above along with the photo of the sensor.

I could be being blind, but I can't see anywhere listing the connector blocks... Just where the wires go to. As I don't have a car... Just the loom and engine, this doesn't help. There are many wires in the 6 or so connectors, some are the same colour, some are interlinked and give interesting readings when trying to trace which is which.

The lack of info on the connector blocks... Known as T6a, b etc is the main reason that it's taken such a long time to work everything out with my wiring.

MG

[UrS4boy]

MG: Based on the fact that what you are trying to do, i.e. install an AAN in a T3, the only thing that you should want/need is the coolant temp gauge. You don't have the automatic climate control so no need to worry about the Blue/green wire. You don't have a mirror control module and you might have the 3 pin MFTS (you'll have to check) so no worries about power in the Black/blue wire (Note: you might end up supplying switched power to 3/+). You don't have an Autocheck module so you don't need to worry about the Blue/yellow wire. That leaves the Brown/yellow wire from pin 1/T to be connected to the T3 water temp gauge (assuming it had one, splice into the wire to the gauge).

Remember for the AAN, the MFTS does not influence the ECU. The ECU gets its coolant temperatures from the G62.

http://forums.quattroworld.com/s4s6/msgs/20985.phtml

You have seen this AAN ECU pin-out post, right?:

http://forums.quattroworld.com/s4s6/msgs/21009.phtml