Yeah, I have now fixed two inop odometers on two different Volvo 240 in the past year, but this time my '89 is grieving me. The first time it was an electrical problem and getting the "guts" from a '92 Volvo 240 fixed the problem. Now six months later it is inop again! This time I found the gear having one broken tooth. The broken tooth was stuck on the old Assembly, and I had ordered a new gear "plate" assembly where you have the two gears. Installed and no workey da. I even did the try turning the gears with a sharp plastic pointer thing. Still no work.
On two occasions, I did note that at start up, the speedometer would jump way up, maybe another electrical problem? It doesn't do it every time though.
Tried the wait a week thing. No go. Maybe the 12 Gage Remington 870 mod will be in order.

 

Well I took the cursed thing apart again, I changed the gear cluster out, and the electric motor that drives the gear. Still inop. Any Ideas?

 

I would bench test it to see if the stepper motor is stepping. Take a look at this page: Electronic Speedometer Notes

 

Wow, that article is over my head, I don't have an Oscope.
I do have a D.C. power supply that I could attach to the board, but would have to scrounge up a the connector from a junk yard.
Thanks, and God bless.
mike

 

No need for a scope but you do need an AC signal. I believe he used an 12vac supply for the signal (it's been a while since I read the article). The ac source acts as the speed signal from the differential.

The main thing you need to test is whether the little stepper motor in the OD is stepping. Hard to do with the unit in the car. Many times the solder joints to the stepper motor crack and get an intermittent connection. They can be re-soldered if you have a soldering iron.

 

I don't have an AC generator, I do have a good soldering iron, I do antique radio repair as a hobby, so I have some meters, and such. All of the junked out 240's in the local yards and there are a total of 5, ALL have their instrument clusters removed, and then the rest just dumped in the back seat of trunk, the odometer gears removed and sometimes the circute board removed from the cluster as well.

 

Try resoldering the solder points on the stepper motor. It might solve the problem.

When you replaced the odometer gear, did you make sure you found all of the missing teeth? They will get in there and jam the whole thing.

 

Yes, it had only one broken tooth, bent over and not in the "works" I also made sure the rest of the gears and wheels moved freely. That is why this has me stumped, I replaced the gear and it should work.