I have a '92 B250 with the Aero conversion pkg. The speedometer needle occasionally moves, usually rocks biack and forth and will stick at 100mph. The odometer is completely non-functional. The guy I bought it from said the trans. had been rebuilt before he owned it and most likely something broke off when re-installing the transmission. His words not mine. I'm wondering if the vehicle speed sensor is what I should be replacing and if so, where is it?

Any ideas are much appreciated!!

Thanks,

Geoff

 

Change the speed sensor, it's on top of the differential.

 

My 98 1500 6 cyl has a similar quirk. Above 30 MPH its fine but drops back to 0 at 30 MPH. Won't even come off the peg till I hit 30 MPH. Had it tested for accuaracy and above 30 MPH it is accurate. Even the odometer doesn't register during the acceleration to 30 MPH. I put about 6 miles a day comuting to work which doesn't show up on the odometer.

 

Thanks alloro,

I will change it this weekend and post the results. Much appreciated!!

Geoff

 

Ok I replaced the vehicle speed sensor on the side of the transmission and the speedometer seems to be partially functioning. It gets up to about 50mph and does not surge to 100mph and back to zero. So it seems its working but not accurate. The guy at O' Reilly said the one on top of the differential is the wheel speed sensor and the computer uses signals from both and computes an average to give the actual speed. I guess I'll order the wheel speed sensor and hope for the best. By the way the odometer is still not working at all.

I'll post results.

Thanks,

Geoff

 

If the speedometer works and the odometer doesn't, then the problem is inside the instrument cluster.

 

Today I replaced the speed sensor on top of the differential. After a test drive it does not seem to have made a difference. The speedo works but still seems to be 15-20mph lower than actual speed. The end of the sensor is still magnetized so I am assuming it still works. I don't know what can go bad on those other than it becoming de-magnetized.

Thanks Alloro for the direction on the odometer, I'll be getting into the dashboard to see whats going on there.

Geoff

 

FWIW, your whole problem between the odometer and the accuracy issue could be in the instrument cluster.

 

It's probably the gear inside the cluster. I had to replace the one on my '90.



It's the little green gear in this pic (not mine) - mine was either white or black (I can't remember now):


I got the replacement gear here:
http://www.speedometergears.com/chrysler-odometer-gears

It's the first one on that page. I didn't have to replace the second one to make mine work.

 

Leeann,
Thanks for posting the info. I pulled the gauge cluster out today to see if anything looked bad but unfortunately didnt see anything. The speedo in your pic looks a little different than mine. Mine does not appear to have a gear in that location. It looks more like a small coil on the shaft of the speedo needle. It does have the circuit board like your pic.

Next try might be the junkyard to find one thats the same...worth a shot.

Geoff