I have a 1993 Volvo 240, my odometer completely stopped working, it ironically will work sometimes once in a blue moon. I have read about changing the gear but in my Bentley Manuel it says it is all electronic. My speedometer works just fine too.

 

Supposedly the bad speedometers, with leaking capacitors, we're from '91 to '92. But I have a '93 940 that was working fine until one day it just stopped. Pulled it from the dash and I could see rusty leakage on the circuit board. I tried to clean it up but didn't make any difference. Got a used one from the local pick-n-pull for $20. Or you can have them rebuilt for around $200.

 

My first thought would be that the odometer drive gear is toast. You can buy those all over the place and I think that its the same gear that goes bad on the old 850. As soon as digital odometers came into vogue, the problem went away.

 

the speedometer may be electronic but the odometer is electro-mechanical with an emphasis on mechanical as in a little box of tiny plastic gears.

Moe, the 91/92 740/940 have a completely different speedometer than the 240.

 

Didn't know that. Since his is a '93 are they the same. And if his does work once in a great while then the gears have to be working and it's the electronics that are shot?

 

sorry, I shoudl have said, ALL 740/940 speedos are completely different than 240. the 91/92 740/940 speedos are unique to 91/92 740/940 and have their own extra sets of problems

 

That's a common problem with our 240's as they age. One little gear decomposes and eventually breaks a tooth or 2. Instructions to replace and the part are available numerous sources for around $25. A DIY-able job; be sure to clean ALL bits of the broken gear(s)-otherwise you will get the sometimes-works and sometimes doesn't situation. And remember NEVER reset the odo while the car is moving- that's what usually finally destroys the gears.