Temperature gauge

I need a wiring diagram for the temperature gauge please . It is not in the Haynes manual. Or if someone has the patience to explain how the red and yellow wire on top of the temperature sender ends up in the cluster? When i short the sender nothing happens to the gauge. But the gauge  works sometimes. Thank you.

Anyone please??? I hope it is not a how long is a piece of string question?? A photo of a page with diagram would be great. Thank you.

year/model, would be nice, IIRC it is an 84, and I don't have the schematics for that specific year.

1989 MK1 golf gti cabriolet... thank you

In my Haynes which goes up to 1995, the red/yellow cable goes from the sender to D29 on the relay plate/fuse box, and from there to the coolant level relay (normally a 42 or 43). Another red/yellow comes out of B7 on the relay plate/fuse box, and goes to the guage.

Hope this helps

Thank you very much. My new Haynes only goes to 1992.???
Anyway I will have a look then with that information.. might be the wire from B7 to gauge. The gauge worked solid for a week then I took out cluster to be repaired (rev counter) car didn't move for a week put cluster back in. Still no rev counter and no temperature gauge. So the only wire to move was that B7 to gauge (I think!).

On the cluster t14/4 is the red/yellow wire to the gluster water temp gauge.

It goes to the yellow/red wire on the single pin (usually black) sender on the water outlet flange.

I would check for continuity between the Sender end and the Cluster end.  If that has continuity then you have either a sender issue, or a issue between pin t14/4 on the connection, or a issue with the water temp gauge.

Now with that being said, did you add a new ground (EARTHING) point to pin 2 of t14 (brown) to the frame behind the cluster?

Have you replaced your main Grounds between the Battery and frame and frame to engine.  If you haven't them you are throwing hot water in the wind.

The water temp gauge and the Fuel gauge, along with the rev counter acting the fool tends me to think that your issue is the cluster (clocks) unit.  

Check for 12V B+ on pin 14 (black) and Pin 2 (brown) on the cluster.

If you have that there, then check the 10V stabilizer (chip looking device with 3 legs) The middle leg to pin2 (brown) is ground.  

The other 2 legs are 12VB+ from Pin 14,  and 9.5-10V to pin2(brown).

If you have that there, then check the water temp gauge for 10V or your reading from the leg of the stabilizer to ground on the temp gauge (big nuts).

If you don't have 10V, then check from the frame ground to the gauge.  You should have 10V, if you don't then your issue is the mylar circuits between the pins and the
Gauge or 10V stabilizer.

Read more about it here.

How to fix your flaky temp gauge, and test it.
Repairing your Flaky Water Temp Gauge | Volkswagen Owners Club Forum

And

How to back feed your Broken mylar.
90ish Cabriolet Mylar repair for 10v stabilizer. | Volkswagen Owners Club Forum

my fuel gauge is ok. yes I put in the earth behind cluster.

IF the fuel gauge is working then your issue is either the continuity between the sender, and the Gauge or the Gauge itself.

As a test, Short the sender wire to ground (key off).
Then measure for resistance between Frame ground in the cabin, to PIn 4 yellow/red wire on the cluster connector, if that reads 0 Ohms, or maybe 0-5, then your issue is between the pin4 and the nut of the water temp gauge so test that connection  If that is 0 Ohms, then your issue is the Gauge and you probably have the cold solder joints on the studs as I have mentioned before.

Removal of the Gauge, cleaning the old solder out, and adding new is the key.

You can test the Gauge in the cluster by applying a 9vDC battery to the 2 pins (not the middle).  The Gauge should deflect to 3/4 to full hot….Leave it there for 2 minutes to see if the pins heat up and the gauge goes to 0…. (cold solder joints.) if the Gauge doesn't move, then you either have a really bad gauge, or Cold solder joints no way around that save for removing and repairing.

Of the 4 Cabriolets that I have owned, I have had to repair all 4 water temp gauges for cold solder joints.

You rev counter issue is probably ground as well and if you fix the Temp gauge I would imagine that your rev counter will start working.

I had an issue with the 10V stabilizer that allowed the Fuel gauge to work, but no water Gauge, and the rev counter was off by 800 rpm……  Which is where I found out that backfeeding it from the 10V stabilizer tended to correct all issues.


 

Thank you Briano... I will get all that tested.. The gauge works when I drive over rough ground for a while then might not work the next day !!

Temperture gauge sorted. it's working now. We did the 9V test on it and it didn't move. so we undid the nuts and touched the copper and the gauge moved. so we put some copper grease around and put nuts back on and it worked. ! So we're thinking either the track wasn't making contact there or the gauge is faulty. So if the gauge goes again soon it must be the gauge.
Rev counter is the next thing. I need to find a new one I think.

 

Thanks for letting us know how you fixed it.
Sorry can't be an help wit the Rev counter.