I am working on a '92 240 for a friend. Initially the speedometer worked fine but the odometer did not work. She wanted to fix or replace the odometer. After some searching on the Internet, I found and confirmed that the problem with the odometer was a broken tooth on the little gear. I ordered a new gear and installed it, put the instrument cluster back in and then not only did the odometer still not work, the speedometer has stopped working. Note: I put the instrument cluster back in and the speedo had continued to work while the gear was on order. When I removed the instrument cluster the next time and replaced the gear, the speedo quit.

The other lights and gauges work, all except the speedo and the odometer. Being an electronics technician by trade, I looked over the instrument cluster circuit board and touched up many of the solder joints; I have confirmed that the speedo head is seated on 4 pins on one side and a single pin on the other. I have measured 12 volts on one of the wires on the connector which attaches to the back of the speedo head. I have removed the instrument cluster, placed a meter set to AC volts across the two pins which carry the signal from the speed sensor in the differential to the speed head. And with the car moving I am measuring a signal across those two pins.

We then ordered a good used instrument cluster off of ebay, which reportedly was tested in a running Volvo with all gauges and lights working. All except the speedo and odometer work when I install this new instrument cluster in my friend's 240.

So, I am at a loss for what to try next. I am open to any and all suggestions and would appreciate any help or advice.

Thanks in advance,
Tom McMillion

 

Are you sure you have all the proper wires hooked up?

 

Thanks for asking. Yes I am definitely sure I have all of the wires correctly connected. When I first pulled the instrument cluster, I read up on the procedure which is well documented with photos on the Internet. I also listed on a piece of paper where each wire and each connector wen. Also it is virtually impossible to connect any of the three connectors backwards or off by one pin or something like that. All connectors are keyed and only fit one way.

I have also removed all of the fuses from the fuse panel next to the driver's side door, and cleaned the terminals where the fuses attach. And with the battery disconnected, I have measured and verified continuity across all fuses in that panel. I have a PDF file with 23 pages of wiring diagrams for a '92 240. I have verified that there is 12 volts from ground to the connector which supplies power and the speed sensor signal to the back of the electronic speedometer head.

I guess I don't have any additional details to offer at this time.

 

hello was wondering if you could tell me where to find a a connector plug for the rear speedo sensor mine is shot 90 740 gl sd thank you in advance p.s cheap as poss.

 

Junkyard is your best bet.

 

I have a 92 940turbo and my speedometer and odometer don't work but the rest of the gauges work. Some of my research found it is the gear in the cluster has broken teeth others say its the plug on the back of the rear differential. I pulled the plug in the diff but its small and simple and can't see why it would be the problem. I picked up a used cluster from a junk yard put it in and it still isn't working, yes I know that this cluster could have a worn out gear as well. Any advice on the next step I can do?

 

mine quite working and it had come lose at the pumpkin. you have to jack the car up by the frame so the rear can drop down it's located toward the top and to the back of it. the wires rot and break off easy fix with a soldering iron.