Renault Alpine GTA Turbo 1989 the speedo has gone mad

Help - my speedometer has gone mad - any idea's if it's possible to buy a new one??? Seems ok until you get to 20+ miles per hour then it bounces about between 140 - 160 mph and won't stop until you come to a standstill - all help gratefully received!

Hello ,welcome .
Sounds like a dodgy sender or bad connection .
I do have some quality used ones in stock though if not

This topic has been discussed many times before. A quick forum search should throw up several threads discussing all the possible causes. Try reading through these:

http://www.renaultalpineownersclub.com/ ... ght=speedo

http://www.renaultalpineownersclub.com/ ... ght=speedo

http://www.renaultalpineownersclub.com/ ... ght=speedo

Two things spring to mind going on what you have described, the only way the speedo can over read is by the corruption of the speed signal passing through the car from the speed sensor to the speedo, in which case there is a possibility that the screening of the cable has lost its earth somewhere, which might be a poor connection in connector R17 in the pic below, and the other is the speedo driver transistor BC 337-25, on the speedo circuit board in the instrument cluster feeding the speedo motor, going into thermal runaway, The only way to check this is by substitution of the transistor...... pic two.
I would go for checking and cleaning R17 first, as these connectors seem to give members quite a bit of trouble

[phildini]

Don't Panic!.... My GTA did that, I just disconnected the battery for few min and on again job done

Oh ..... and I think I pressed for 10 sec the reset computer switch thing....

I have found that if the battery is a bit flat and the car only just starts that the speedo will be erratic. I just drive for a short while and stop then restart the car and all is well. The low voltage on starting does appear to be the problem.

I have found that if the battery is a bit flat and the car only just starts that the speedo will be erratic. I just drive for a short while and stop then restart the car and all is well. The low voltage on starting does appear to be the problem.

Agree with Alan. I've been stuck in the garage with a too-low-charge battery going nowhere but reading 170! You should see the odometer go round at that speed!