temperature guge

Hi all,my temperature guage has stopped working and sometime springs back into life ,i put a new sensor in but still the same  the red light comes on at start up and goes off,any simple test ?thanks matt

Yes, in the Archive section, for how-to's under Briano
I have a list of How do I do thats.

One is a wonky water temp gauge.

First question is the Year of your ride??
Why? Because if you have a latter 90 ish as in Cabriolet, you can test it with out turning the car on.

A 9V DC battery can be used to give the Gauge voltage / current from the engine compartment and the gauge will deflect if the gauge doesn't then you have a gauge or wiring issue between the sender and the gauge.

Since you say that it is intermittent then the issue is usually cold solder joints with in the gauge itself.

This too you can test by removing the Fascia and controls
Tilting the cluster and apply the 9V dc Battery to the rear of the cluster and watch for the needle to move, then leave the battery on as the gauge will get hot, and if it flakes out, then it is a cold solder joint on the wires.

All this is in my how to.

Recapping,

The internals of the water / fuel gauge are the same.

If both gauges are wonky at the same time then that is the 10V stabilizer issue.

If one or the other are off, and you have verified that the sender is good, then you proceed.

The internals of the Gauge are 2 studs that connect the gauge movement to a source for ground and 12V.

This is a Bi-metallic spring wrapped in Nicachrome wire (same wire that is in a toaster, but smaller gauge.)

As this spring gets heated the spring moves and deflects the needle.

If the Gauge starts, stops, and then comes back on, it is because the joints where the Studs come through the housing get hot enough to melt the solder away from the wire, and or stud.  It opens the circuit the spring cools off and goes to 0.  The cold solder can re-attach
the wire to the current source and the gauge starts to move.  A never unending cycle until you get the older solder off clean the connections and re-solder.

Where are the links?

View topic: My DIY list of things for a 90ish Cabriolet (digifant2) part 1 - The Mk1 Golf Owners Club

thanks for the reply mine is a 89 g reg,regards matt

update guage started working tonight it went upto 3/4 but the fan didnt kick in! where is the stat ?i ran the heater on full but didnt seem too hot,can someone tell me where the fan stat is so i can take it out and put a little heat on it to test its working? regards matt

The fan switch is in the lower left hand side of the radiator. Below the Battery tray area, I suspect that is why they call it the Radiator Fan Switch….

Yes you will get (douched, wet) by removing it.
If you want to test it, I suggest buying a new one, test that, then wrap t with teflon tape and remove, and re-insert new.  If you are really quick about it, you don't loose to much fluid.

In the Archive section I have a DIY on how I flush and back flush my Radiator, and if you haven't done it, you might just want to and install a new t-stat as well.


You did jump the motor to 12 and earth to verify that it spins?…Easier to find that the fan doesn't work first.

 

thanks again i will try taking the 12 and going to earth what colour is 12? also if my temp guage is playing up im guessing its probaly not getting to 3/4 but alot less? wil try when i have a day off!