1990 740 2ltr Speedo (again)

Hi,

a while ago I posted about an issue with my speedo packing up. I've finally
got round to sorting it out and have hit a brick wall in terms of progress.

I managed to find a working speedo in another 740 (same year, same engine
etc). I drove the donating car to check the speedo and it worked a treat all
the way up to 50mph.

I've now transplanted the known working speedo into my 740 and, guess what,
it ain't working!

I've check the contacts in the dashboard and they're clean. What would you
suggest I look at now?

Thanks,

Richard (keen amateur)

 

Make a thorough check of the speed sensor fitted to the rear plate of the
differential. It has a two wire connector which dissapears into the luggage
area (boot or trunk). This then follows the loom to the front of the car
along the left hand side, turning up under the dash and crossing over to the
instrument panel. In the luggage area the wiring (a twisted pair) is routed
via a small black plastic terminal box on rear face of left rear wheel arch.
If your car is fitted with ABS the sensor wiring splits to ABS and
instrument panel as the speed sensor acts as the rear ABS sensor as well.
Then check the panel printed circuit for faults.

All the best, Peter.

700/900/90 Register Keeper,
Volvo Owners Club (UK).