Hello. The speedo on my 91 740 stops at 45. Wont go higher than that no matter what I do. Any ideas?

 

the 91 and 92 740/940 speedos get flaky with age. sometimes replacing the capacitors and resoldering the circuit fixes them but it didn't on my 92.

and you can't swap different years, there's various engineering changes that make them incompatible.

 

Okay I'll try that. Thank you. So odd that it stops at 45 rather than not working at all

 

Our clusters are electronic then right? Someone suggested it could be the cable from trans to cluster but that would be analog correct

 

if the cable was bad, you'd get no speed readings at all. the sensor in the rear axle outputs some number of pulses per full rotation of the rear axle.

 

okay so I should start at the capacitors and go from there

 

well, its worth a try, if you're competent at PCBA repair and soldering.

I think this is the guide I followed, and I definitely had leaky capacitors, with black crud under the chip similar to the picture there, I quite carefully cleaned it all up, yet it didn't fix the problem for me.
Notes on 740/940 Volvo Speedometers

 

Thanks. I'm also exploring the route of replacing just the speedometer in the cluster but I'm not sure how that works yet

 

yes, the speedo comes out of the cluster and can be replaced seperately. removing the 740 instrument cluster requires a pair of flat thin steel tools you insert into slots to press some clips so the metal bezel will come out, then the instrument cluster comes out pretty easily, but you need to be very careful around the needles.. its been a few years since I touched one, so I don't remember any specifics past that. when its all out and apart, its a good idea to carefully polish the plastic lens, reducing any scratches and swirl marks from 30 years of sloppy dusting.

as I understand it would have to be another 91/92 speedo from, a 740/940, they changed things considerably in 93, and earlier ones won't work either as the whole dash got a redesign in 1991 (first year of the 940, the 91/92 740's are essentially a feature stripped 940 w/ left over 7 series body trim and trunk pieces). apparently if you use a 93 complete instrument panel, your gas gauge will be wildly off (at least thats what I remember hearing or reading). also watch out for the 1991 940SE, that's really a 960 and has a completely different dashboard.

 

Do I have to take whole dash apart to pull speedo? And how do I set the mileage to what mine is if I get another one

 

the instrument panel comes out of the front of the dashboard, as I said, you use two thin metal tools to depress some hudden springs then the metal bezel around it comes out and the rest is easy.

https://www.volvoclub.org.uk/faq/Ele...ngeability.htm

ok, that also goes into all the differences in model years and instrument clusters.


more here,
https://www.volvoclub.org.uk/faq/Ele...anelRepair.htm

and more on fixing thje speedo here
https://www.volvoclub.org.uk/faq/Ele...eterRepair.htm

 

Thank you!!!

 

OH, here's the article on actually removing the cluster...
https://www.volvoclub.org.uk/faq/Ele...ClusterRemoval