Temp Guage light

Has anyone any ideas please why the red light on my temp guage continues to flash all the time even when engine cold? I have checked the water level in the tank thingy and cleaned the probes for want of a better technical term, (i'm no mechanic).

take the plug off and bridge the pins, if that helps the sensor is bust. if not, pull relay #42 or 43, that will disable the level sensing circuit. if that helps its the relay or wiring at fault. if not, its the dash temp sensor, wiring or the clocks

Hi John.. Thanks for the advice. I have bridged the pins and that did not solve. Tried looking for relays 42 & 43 and cant find them. Are they near the fuse box, if so I dont have any numbered as those? Can you help please?

the relay is clipped above the fusebox, if the car is a lower spec model then the relay wont be there. easy way to tell is to check the top of your header tank, if it doesnt have a 2 pin plug on it then you dont have the level sense system fitted to your car

Hi John, I have the header tank with the two pin plug. My GTI is a very late Campaign model 1984 and the relays are as you say above the fuses. I just dont have any numbered 42 or 43?

I had the same problem but gaffer tape saved the day. there were 2 pipes shorting out againt the temp senser, i  wrapped these lines where they are coming into contact to the temp senser with insulating tape and the red light was no more.

look above the fusebox for an extra relay holder, there should be at least 1 there for the level sensor relay, maybe another one for idle stabilisation circuit.

if you look at the back of the relay holder the one for level sensor is the one with a red/yellow and blue/yellow wire coming out the back of it

Perhaps the mix of water / anti-freeze aint correct   :dontknow:

ive heard arguments for and against the sensor being able to detect anti-freeze mix, im not sure myself but have seen a few cases where it has done the trick. on my own mk2 i ran it on plain water for a bit when i was flushing the system and it didnt trigger the warning

It definately worked on mine. I had been topping her up with water   :roll:  then the light started flashing even tho the level etc was fine.  Added some antifreeze in & hey presto, the light stopped blinking.
Might have just been coincidence tho….   :wink:

I've been reading the Haynes manual searching for a solution for this beeping flashing light. The wiring diagram , with my limited knowledge, suggests that there is only a relay somewhere near the guage?? I'm still to have a close look at the fuse area however, waht can go wrong with the guage/light? Any further advice please?

the relays can die with age, and they can also be damaged by water leaks above the fusebox. in rare cases apparently if the sensors fail and leak water into the plug coolant can wick up the wiring and get into the relay that way? not something I have seen but someone said it happened to them.  then the sensors can fail or get gummed up with crud, removing them and cleaning the sensor tips can sometimes help.  after that the coolant temp sensor can also cause this fault, or a wiring issue or the clocks themselves