Gday mate. I have just repaired a later model vectra with the same problem. it had a dry solder join on the printed circuit of the dash board. you need to remove the instrument cluster and dismantle the cluster this can be tricky if you haven't got experience in this sort of stuff. the fault is in the connection for the ribbon to the circuit board.
Replace the speedo head assembly. It is a sealed unit, with no servicable parts. If the speedometer is working, then the cable and the speedo drive gears are working. The failure must be inside of the speedo head assembly itself.
Why is my Renault megane scenic 2005 speedometer not working?
The gauge has failed.
Yes and no, the actual odometer and speedo assembly will fit but the the whole VP cluster will not, although it will bolt in the wiring is different and you will fry the dash or under dash wiring.
Switch ignition OFF, Press and hold button at speedo. After approximately 3 seconds the letters "INSP 0" will appearin the display. Continue holding button at speedo,depress brake and switch on ignition ON. The letters "INSP---" will start flashing in the display to be replaced after approximately 10 seconds with the message "INSPxxxx Km". Release button at speedo and brake pedal and switch off ignition.
If the speedo stops also, it is the speed sensor. If just the odometer, take it to a speedo shop.
Check Ignition switch. Does your speedo or tach work? If not it's the ignition switch. The transmission needs 12volts to operate and if the ignition switch is not working right you will not have first gear or overdrive, the suburban will try to take off in second and seems like your tranny is slipping!
Hold the speedo reset buton down when tirning on ignition after about 30 seconds it will reset.
Turn ignition to 'accessories' (not 'ignition on'), then press the trip computer button for about a second, and release. The display should flash 'km/h / mph'. Press the 'M' of the hours and minutes clock adjustment, at the left of the display, to select the speedo reading you want.
Hey Tony==Either manual or electric spedo if this happens the problem in in the speedo and needs to go to the speedo shop. GoodluckJoe
Replace the Distributor, i did this on my 87, and my speedo started working again.
could be the speedo cable?