Temperature warning light constant flashing

Can anyone help me please my temperature light flashes all the time this has only come on recently it comes on the moment you start the engine even when from cold. I have recently pur new radiator waterpump thermostat header tank and i know all these are fine and the car does not run hot .fan kicks in as normal. But the light flashing is off putting .. any sugestions or help please.

Iam wondering myself if its an earth fault as i discovered a earth strap lose from the engine bay ???

Yes, it's a common problem, can be a variety of causes.

If you do a search on the forums using the Google search option in here (scroll down the page you are on until you get to the black section and you will see it - well certainly if you are looing via a tablet/iPad, not sure if other devices it looks same) and then type in temperature light flashing you wil get lots of topics to look at.

This is just one of them, with a solution, you will fing others with different issue fixes.

View topic: Temp warning light flashing - The Mk1 Golf Owners Club

if it has ,low coolant sensor in header tank unplug it and bridge the 2 pins together. if that doesnt help try pulling out the 42 or 43 relay above the fusebox.

if shorting the plug stops it remove the level sender and clean the pins. if still not fixed replace the senszor

rubjonny said

if it has ,low coolant sensor in header tank unplug it and bridge the 2 pins together. if that doesnt help try pulling out the 42 or 43 relay above the fusebox.

if shorting the plug stops it remove the level sender and clean the pins. if still not fixed replace the senszor

It isn't a dead short, bot about 150 ohms.  
If the coolant sensor in the tank can be removed you can try cleaning the pins of the sensor, they can get calcified and stop working..Cleaning them is a good thing.  Also if you aren't using a 50/50 blend of A/F to water, you can change the value of the resistance of the coolant and cause the same thing as you are describing.  Too Straight mix of AF causes issue and too much H2O to coolant will cause funny things to happen as well it is like the "BABY BEAR" and has to be Just right.

aye but if you short the pins on the plug together this tells you if its a problem with the level sender side of the circuit, or an issue with the wiring, sensor or the control relay

one thing that can happen is the level sensor splits at the pins and coolant gradually works its way up the wires and rots out the control relay, I've seen it often on wiring looms I've had in for conversion

another issue I've had is with a faulty coolant temp sensor causing the light to be triggered. even though the dash gauge reads perfectly fine, some kind of problem with it triggered the light even when the engine was started cold. I went crazy messing about trying to figure out the issue, before I finally resorted to trying the temperature sensor from my own car and problem solved!

All I can think of was it was starting to fail inside and would intermittently short to ground, triggering the warning. but not for long enough that the actual reading would change on the cluster

Thanks a lot guys i solved the problem turns out to be the sender plug had slight corossion so i cleaned it up and now works fine .thanks everyone for your hrlp/solutions

Good Day gents Ryan here I'm new to the site my problem  I'm having  is the red lihgt on the water temp gauge  doesn't  come on at all how ever if I put 9v directly  to it ,then it works  

Year an model are nice to know, as the latter Cabriolets had a low coolant switch in the expansion jug.

But some of the earlier ones had a Gauge test circuit, and some don't.

The Coolant temp circuit sender can get flaky, or bad and that is on the water outlet flange, and usually black single pin connector. The wires get brittle with age, and
loose tension or break if man handled.

You didn't state where you put 9V on it at so I can't guess where the issue is.

Water Temp gauges get internally cold solder joints that make them erratic/flakey/non-functional.

In the archive section How-to's or click the link on my signature and I list the typical issues that I have seen with them.

Briano1234 said

rubjonny said

if it has ,low coolant sensor in header tank unplug it and bridge the 2 pins together. if that doesnt help try pulling out the 42 or 43 relay above the fusebox.

if shorting the plug stops it remove the level sender and clean the pins. if still not fixed replace the senszor

It isn't a dead short, bot about 150 ohms.  
If the coolant sensor in the tank can be removed you can try cleaning the pins of the sensor, they can get calcified and stop working..Cleaning them is a good thing.  Also if you aren't using a 50/50 blend of A/F to water, you can change the value of the resistance of the coolant and cause the same thing as you are describing.  Too Straight mix of AF causes issue and too much H2O to coolant will cause funny things to happen as well it is like the "BABY BEAR" and has to be Just right.

From “Temperature warning light constant flashing”

I have the exact opposite  mine is the one with the coolant temp sensor  I rebuild  the cluster all new tem and feul Ganges  the temp Ganges works fine but the red lihgt on it doesn't  work at at all ,but if I take a 9v batry to the back of it positive to the right leg and negative  to the center  thin leg the lihgt works

 
I have the exact opposite  mine is the one with the coolant temp sensor  I rebuild  the cluster all new tem and feul Ganges  the temp Ganges works fine but the red lihgt on it doesn't  work at at all ,but if I take a 9v batry to the back of it positive to the right leg and negative  to the center  thin leg the lihgt works

does the gauge still work as expected? check all the nuts on the back of the gauge are tight and dont have insulating washers under them as they provide the electrical contact to the board

you should get a test flash ignition on, then if coolant is low (if you have the sensor and relay that controls it fitted) plus overheat

you can test the overheat warning by shorting the coolant temp sensor wire to ground, the gauge should go to full and light flash

The gauge  does go to full but no red light  I will install  new relay  it's 43? If I'm not mistaken

43 is just to warn low coolant, if you get no light flash when shorted or test flash ignition on its a cluster/guage fault

But that's exactly my problem  it doesn't  flash when I turn on the ignition  nore does it tests flash the gauge  is brand new oe one witch  is VDO

model and year are nice to know.

Well the harness  is from a CITI SHUTTLE THE CLUSTER IS FROM A 2009 CHICO    BUT THE ENGINE  IS NOW A 1.4 CARB AND THE BODY IS 2009 MODLE

Sorry but that is a little too new for me as my limits for MK1's are mostly VW Westy Rabbits and Diesels and 89-93 VW Cabriolets.

EXZACTLY  the citi shuttle  is a 92 model  and the wireing has remained  EXZACTLY  the same from 83 to 2009 in South africa  

So the wireing is from a 92 model