Speedometer/Odo/Cruise Not working (99.5 TDI Golf 5-speed)

So my 99.5 Golf speedometer/odometer/cruise stopped working along with a wonky fuel gauge. Just like that a few days ago.

Did a bunch of searching on here and tried all the usual sugestions including 2 new speed sensors (just in case the first new one was bad), the sensor drive gear is not broken or stripped, it turns as it should when you drive the car, fuse #7 is fine, all the wiring looks good and the ground to the switch checks out.

Any more places I should look/check?

Thanks for your time.

Did you replace the drive pinion or just inspect it?

I had a similar issue a while ago. Replaced the sensor. All was good - for a couple of months then it started all over.

Bought a new sensor. This time I pulled the pinion out of the trans to inspect it. The sensor has a square pin that fits into a square hole in the pinion. That square hole was all rounded off - undoubtedly due to the old sensor starting to seize up.

Replaced the pinion and all has been good for thousands of miles.

The pinion is two parts - 02A 409 197 is the pinon shaft, 02A 409 193 is the "guide". Get them both as you'll likely ruin the guide if you try to pry the shaft out of it.

I'd do a search on "coolant migration".

-J

Thanks for the tips. I was able to ride on top of the engine while my wife drove the car so I could see that the sensor was indeed spinning. I was able to even reach down and put tension on it with my fingers and it seemed to be spinning and not slipping but I will check again that its not worn out like you suggested.

I read about the "coolant migration", but all is dry there at the tank plug.

When checking the square hole in the pinion for signs of being rounded out, also look at the square pin on the sensor. Mine showed obvious signs of slipping in the bore - the edges were all chewed up.

If the pinion is OK (and it might be worth $10 to replace it just to be sure) then it's time to check the wiring. Wiring that "looks good" doesn't mean the wires are conveying electrical signals properly.

First check for chafing or broken wires right at the sensor connector.

The wiring to the sensor is pretty simple, only 3 wires.

Pin 1 (blk/white) is 12v from fuse S7. I assume you'd get 12v only with the ignition on. Check for a blown fuse, too.

Pin 2 (white/blue) goes to the instrument cluster, blue connector, pin 28. Check for continuity.

Pin 3 (brown) goes to ground somewhere in the cowl plenum. Should have continuity to chassis ground.

Todd

Hi Todd, Thanks for the help.

I finally got a chance to do some testing and it is the power wire (blk/white) to the sensor that is not working. No 12v at the sensor, but the fuse is good and the back up lights are working.
The other two wires check out for continuity to ground and to the back of the cluster accordingly.

Not sure where to check next.

I don't want to thread jack, but I'm having the same problem. I checked group 3 of the trans and I have a speed reading there, but the speedometer just crapped out.

I have the old trans and not sure which one is the speed sensor. Can anyone point me in that direction?

I did a search on the forum and found the sensor that goes to the speedometer. I pulled the connector and there was some fluid and blue corrosion in there. I sprayed it with electrical contact cleaner and compressed air. Works fine now. I'll keep an eye on it for coolant migration. I washed the engine a couple of times recently and I hope it was just water.