Vdo Speedo Stopped Working

[Guest ians2B]

I have a vdo speedo which is pulsed by a four magnet setup on the propshaft. Nothing seems to be damaged there.

 

Speedo lights up and the needle gives a little jump and the total mileage is displayed when I switch on the ignition.

 

But when I drive the needle doesn't move !!!

 

Was working perfectly!!! for the last two years!!

 

I have jacked the rear up and run the car in gear and moved the position of the sensor but this has not changed anything.

 

How can I?

 

1. test the sensor for magnets to see if it is generating a pulse

2. test the speedo, suppose that could be faulty but how can I check it its electric?

 

As always cheers for anybodys help.

[Snapperpaul]

You can check continuity of the cable with a simple bulb and battery (disconnect from speedo first) moving the prop to see if the magnets open and close the switch.

 

If there is a fault with the speedo this is harder to find, back to the manfacturer.

do check all your connections for broken wires or joints.

[niduncan]

I use the diff flange bolts on my VDO speedo and to test it I used a pillar drill:

 

 

 

I have since changed to a differnt type of sensor:

 

[Guest ians2B]

Cheers for the responses will try the lighbulb trick.

 

Otherwise as you say back to the manufactureers

 

Ian