I would like how to access the speedometer sensor on differential 92 volvo 960

 

my speedometer failed and it has been suggested to check the sensor on the differential and i don't know how to access it.

 

from "New Member" to the 960 section.

 

Try this link to troubleshooting information from the Volvo manual. This is primarily for ABS but it includes specific information for testing the rear speed sensor on the differential. This is from a 1994 Volvo 960, same body style and same drivetrain that you have.

Anti lock brake system including rear speed sensor at differential

Scroll down a little over half way down the page until you find "Rear (Axle) Speed Sensor". It tells how to check the resistance of the sensor up front at the connector which attaches to the ECU, between terminals 7 and 9. Disconnect the ECU connector and with the rear wheels turning check the resistance between terminals 7 and 9. Perhaps easier said that done if you're by yourself. I would assume the rear of the car would have to be lifted on jack stands on a level floor, with the car in neutral and someone to turn the rear wheels while you measure the resistance reading from the sensor at the front of the car, at the point where it attaches to the ECU.

I have not personally had a need to do this test myself. I just found this in a search result. Hope this helps.

 

thanks that is a good idea, that sensor is so buried into the differential mounting apparatus that you can barely see it through a small opening and to replace it looks like one hell of job however it looked intact and chances are the problem may be the resistors in the speedo itself. thanks again ron

 

You're welcome. I hope that helps. I can say from personal experience that my speedometer is on the fritz. It intermittently does not work or will jump a bit and start to read and then immediately stop, often right when I first start out in the morning. If I bang on the dashboard with my fist once or twice it will start working again. If I leave it alone or if I don't notice at first that the speedometer is not working as I pull out of the driveway and head down the street, the up arrow on the lower part of my dashboard will light and the shift mode lights will alternately flash. This will continue until some time after I get the speedometer working again by banging on the dash.

I pulled the speedometer cluster a few weeks ago and cleaned all of the contacts where the different connectors attach to the back side of the speedometer circuit board. I put it all back together (this is my daily driver so I can't leave it out of service to investigate in more detail) and the problem still persists. It's not every morning and not even every day that it does it.

I'm saying all of that to say that in my case I am 100% certain that the problem of my speedometer not working has nothing whatsoever to do with the speed sensor in the rear axle. It is almost certainly a cold solder joint on the speedometer circuit board or some other connection problem in the speedometer cluster itself. I plan to pull the cluster again one day when I have several hours to work on it. It is definitely possible that the problem of the speedometer not working can be caused by the speedometer cluster itself.

 

Thanks Tom these volvo's are great cars no doubt but there are things that come up that makes you want to pull your hair out. In your case since you have to pull it out of the dash again why not get a replacement from a salvage yard that works and save the hours trying to repair yours that is unless you come onto something right away, anyway good luck on yours and i hope i have a little myself. take care tom and thanks again ron

 

The rear sensor is rarely the issue. Usually it's the speedo head, more accurately the diodes inside which go squirly and cause issues.
What symptoms are you having? No speed reading/no odometer may be the rear sensor but any intermittent reading flaws are not coming from there.

 

thanks for answering me lev I was driving and it just quit and of course the cruise went with it now it returned once for a little while then quit altogether and that was a couple weeks go. i'll be interested to learn what you think on this, i sure don't want to tackle that rear sensor it looks like a hell of a job. thanks ron

 

Your problem is not the real sensor if it comes and goes. But the speedo itself is not easy either as the capacitors inside are not easy to change.
https://www.brickboard.com/FAQ/700-9...eterRepair.htm