The spedometer in my 96 Polo 1.4 has stopped working. The needle stays at 0 and the odometer doesn't tick up. Everything else in the cluster seems to work, including the tach. I recently had the gearbox replaced with a used one. What could cause this?

Thanks.

Edited 20 November, 200718 yr by tulanian

Speedo cable not reconnected to the gearbox? Or the cable got damaged?

The spedometer worked for a bit more than a week after the gearbox replacement. Is the cable coming from the gearbox obvious or hidden by other stuff?

The spedometer worked for a bit more than a week after the gearbox replacement. Is the cable coming from the gearbox obvious or hidden by other stuff?

Had a similar problem with my daughters 1.6 litre Polo, 98 model - don't know if your car has same type speedometer.

Her car had an electronic sensor attached to the gearbox on the firewall side.

There is a connector plug to the sensor with 3 wires attached.

One wire should have 12 volts, one wire should go to an earth point on the engine - check less than 0.5 ohms with a multimeter between the terminal and engine block. The third wire is the signal back to the instrument cluster unit. Check continuity on this circuit.

Hope this helps,

regards from down under,

engineerthomson

Okay, now my fuel gauge is behaving erratically. As I'm driving it will drop to below half a tank and rise back up to over full. I've been driving for a week since the last fill up, so I know it's got somewhere between a half and full tank. Could the speedo and fuel gauge problems be somehow related?

Okay, now my fuel gauge is behaving erratically. As I'm driving it will drop to below half a tank and rise back up to over full. I've been driving for a week since the last fill up, so I know it's got somewhere between a half and full tank. Could the speedo and fuel gauge problems be somehow related?

That is a weird fault - might be worth checking that the 12 volt supply and earth connections to the instrument cluster are solid.

Any result from checking the speedometer sensor and connections?

regards,

engineerthomson

I'm pretty ignorant about autos except for the basics. Is the connector plug visible from the top of the engine compartment or do I have to go beneath the car to see it?

Thanks for the advice so far.

The sensor is accessible from above - it is located on the gearbox on the cabin side low down. You might be able to see a small electric cable in that area and trace down to the sensor. Next time I see my daughter with her Polo I will photo the sensor and send it to you.

Well, the speedo just started working again. I was driving on the motorway (first time since the speedo went out) when it started up again. It dropped to zero a couple times on the trip but came back after a second or two. The petrol gauge is also working correctly now. Does this sound more like a instrument cluster problem, now?

Well, the speedo just started working again. I was driving on the motorway (first time since the speedo went out) when it started up again. It dropped to zero a couple times on the trip but came back after a second or two. The petrol gauge is also working correctly now. Does this sound more like a instrument cluster problem, now?

I would suspect an intermittent wiring connection. The vibration as the car travels could cause loose wiring connections to make or lose contact with the terminals where they are attached. Intermittent wiring connection could also be caused by corroded terminals.

Speedo and petrol gauge could be two different faults or could have a common cause like power supply to the cluster.

Check out all connections and make sure they are OK.

Regards,

engineerthomson

Hello Tulanian,

According to my haynes book, the earthing connections for both the speedo and the fuel gauge share a common point. This could explain your problems.

It is a 6MM stud located on the engine head near the distributor on the cabin side. there are 2 wires connected to this stud.

You will have to remove the plastic trim cover over the engine to access this.

Check that the nut is up tight.

I have taken photos of the stud and the speed sensor to help you locate same.

I am not able to attach these to this reply. If you want them email me at

engineerthomson@optusnet.com.au

and I will send them.

Good luck,

engineerthomson

Where is the speed sensor? I dont know where to look.

Edited 24 March, 200917 yr by miikey