Temperamental Engine Temperature Gauge?

Hi All

I'd be very grateful if anyone out there can help me as this problem has been driving me crazy! My engine temp. gauge on my 1990 Cabriolet GTI has been giving me grief for too many years now and I've had enough.  It would either work or not but 90% of the time the needle wouldn't move (from it's 10 o clock position) yet the red warning light would flash intermittently and not even at the same pace.  A bang on the top of the dash with a fist quickly puts a stop to it, until a few minutes later when it starts playing up again.  Combing this fault with an intermittent fuel gauge over the last 2 years (working, then not) plus only 1 working dash bulb at night, you can only imagine the frustration! So I recently bought a new dash foil from VW Herittage (155-919-059/F) and fitted it last week.  Everything worked for about 2 days and I was very pleased with myself as my electrical skills are limited.  However the troublesome temperature gauge and red flashing light are back to it's former state. Once again, a bang of the fist on the dash stops the flashing red light but the needle more often than not doesn't move. It's obviously a loose wire connection somewhere but I haven't the faintest idea where to start looking?  I have to pull the dash out again as the dash light bulbs I replaced have come loose so whilst it's all out I really want to solve this problem once and for all!  The temp gauge is probably the most important instrument on the dash and I'm tired of constantly having to ignore it whilst also having to check under the bonnet before every journey to check my coolant levels are OK! I've just had a brand new cooler bottle installed with new coolant and I don't think the sensor is more than 3/4 years old. My golf runs fine and doesn't overheat and when the temp gauge does work (very rare) the needle never goes above half way. I'd really appreciate any help you can offer!  The only similar post I've managed to find is from a 1983 golf and the problem isn't the same.

Thanks in advance!

Darren

I had a similar issue that then changed to the flashing light and the temp being almost of the gauge (top end) even when started from cold.  

The solution is not quite what you'd expect.  I talked to my car asking why she was punishing me (after several cans of choice ale).  The next journey started the same but half way through the gauge settled down and has been fine ever since.

If that doesn't work. there are some sensors on the coolant flange which comes out of the front of the engine.  Not sure if this is the sensor you mention.

Check the readings of the multipin that plugs into the clocks.  I think rubjohnny had a link showing what the readings should be.  Ill see if i can find it

sounds liek the contacts inside the clock plug are a bit loose, look in the end of the plug and tweak any pins that sit a bit low