Scirocco Register

Hi all, trying to get my temp gauge to work, the red light flashes a few times on start up like normal but the needle never moved despite the engine being got enough to get the fab to kick in.

I've bridged the connector and the needle shoots up as expected so I thought duff sensor, replaced it with the only same fitting "temp sensor" vw heritage sold, a blue one, (part no: 025906041A ) but still got nothing happening

Any ideas?

maybe the needle is broken on the display ? just a thought

Does the GTII have a single pin sender screwed into metal or the 2-pin push in type?

2 pin push type

Two things come to mind - either a duff sensor or an air gap around the sensor - did you top up the coolant and let it run with the cap off?

Had a similar problem on my car, turned out to be a dirty ( bad ) contact between the plug and the sensor. Might be worth cleaning the inside of the plug if you can , especially the earth side.

Sprayed some contact cleaner in the plug so it's clean, also took the sensor out, cranked open the cap and let the water level rise to the brim of the sensor hole then pushed the sensor in (displacing the water) so there's definitely no air in there,
The other day my engine threw it's water pump belt and the needle rose up pretty quick, maybe the stat is stuck open?
I have noticed that the needle does actually move a bit when driving, from below the white zone on the first start up to the middle of the white zone when fully warm

Not quite sure what you are describing above in that last post, but suffice to say the needle is moving now ? If its not moving up to the middle of the gauge where it should be when "normal", then the culprit may well be the thermostat. However, I'm running with no thermostat in my car at the moment and the needle will always creep up to a quarter of the way across the gauge , and if the car comes to a standstill for more than a minute of so, the needle will move up to the central position. Just wonder if it could be the voltage stabiliser on the back of the instrument cluster that might be giving you problems, but would have thought it would affect your fuel gauge readings too then ?

Put your thermostat back in, that will help control the water temperature as they do close when the car is moving and the air is cooling the radiator.

sorry for the late reply guys, if I describe the problem a bit better it may help, crawling around town the needle is at the high end of the white zone (cold zone), on the motorway the needle barley moves off its rest position (not even reaching the white zone) and if you rag it up a hill or drive it hard then stop the needle is slightly above the white zone and the rad fan comes on, ive only seen it rise to the middle of the gauge when the pump belt snapped and I had to drive to euro parts without it

Does your rad fan ever kick in?

Yes it does if your ragging it around or sitting in traffic for a long time

OK, so that implies that the engine is reaching the correct temps - at least in the radiator. To quickly and easily check the temps I would invest a tenner in one of the many Infra Red thermometers on Amazon/eBay etc. - if only for peace of mind. Once you have that, check that the temps are similar throughout the system - especially at the point where the sender lives.

If you have similar temps throughout the cooling system then it's not a flow problem - which leaves you with you sender/gauge/instrument panel.

A notorious instrument panel issue is the voltage regulator on the back - worthwhile having a google to see if others have had similar problems.

had a search and yes the voltage reg does seem to throw up similar problems, also explains why the fuel gauge is a bit erratic, ill pull the cluster out and see what kind of voltage im getting off it,
does anyone know where I can get a replacement regulator if it is this problem?

Yes, I've got a new one sitting on a shelf ….but check out how much they cost before I offer it to you.