So I'm going through my recently now again running functional '94 Regina 940 wagon, I got it on the road and legal this past week, and forgot the spedo is shot. I'd like to know how fast I'm going...

I've seen some online stuff saying that there's a circuit that can go bad behind the in dash display, but this SEEMED to be linked to the cable, as in the needle would bounce, from 0 to the speed being driven just before it failed, or would work, not work, etc.

I can't remember if this thing runs of the transmission or if it's Saabs I'm thinking of, it's been awhile since I've been ambulatory.

thanks guys!

 

wires are at differential. as long as they are intact your trouble in the speedo itself or the circuit board behind the instrument panel. try refloating the solder points, if that doesn't do it, the speedo's capacitors are bad (most likely scenario).

 

to clarify what lev said... this is an electronic speedometer, there's no mechanical cable like there was on most 240s. the speedo sensor is in the back of the differential, upper third, has a twisted pair of wires (brown or brown-white, and green-white) that go from the differential to the left side of the trunk compartment behind the rear wheel well, then forward under the left side door sills to the dashboard where it goes to the speedometer in the instrument panel.

failure modes can either be that wire is broken by the speed sensor, its broken somewhere in the middle, or the speedometer itself is having electronic problems. the speed sensor itself rarely fails as its a simple magnetic coil.

 

Thanks guys. That'll put me in the right direction for sure. I was thinking about an older 240 I had now that you mention it, that the spedo went on.