Odometer won't turn

[cabinetman]

I had purchased a 1988 Chevy ¾ ton pickup that originally had an overdrive transmission I am not sure if it was called a 700R4 at that time or not. The previous owner changed the transmission to a TH350 because he was pulling a lot. The speedometer works fine but the odometer does not turn. Can anyone advise me as to why that may be? I have noticed a white plastic 4 contact pigtail connector hanging loose above the tranny and transfer case. Any help would be much appreciated.

[cabinetman]

I don't feel so bad now, I usually can figure odd things like this out on my own but with no replies to this thread I guess I am not a total idiot.

[piecesparts]

I believe that the odometer still feeds off of the rotating assembly of the speedo, even in this truck. I may be wrong. So if the speedo turns, then the odometer should respond to it.

[bwood]

The same thing happened on my 91 GMC Sonoma, the trip counter quit working one day. It didn't really bother me, but about a week later so did the odometer. THen I started to scratch my head. I pulled the cluster (also to replace some lights), I couldn't find anything serviceable, so I put it back in and it worked until I sold it. Don't know what I did other than replace the bad guage lamps.

[cabinetman]

I had a replacement cluster from an '89 that I was going to replace it with but found out that from '88 to '89 they changed the electrical harness. So I've had mine out and back in, just didn't have your luck.

The more I think about it the more I believe it has to be electrical some how, some sort of a pickup sensor or something.

Well swap meet season starts in a little over a month, maybe I can find a replacement cluster. I'll just dink with the one I have for now and maybe get lucky.

[JohnO356]

Your odometer and trip mileage are driven by plastic gears which just wear out. My trip mileage quit working long ago on my '88, and now the odometer sometimes takes a few miles before it rotates.

[cabinetman]

Would it be safe to assume that that plastic gear is on the other end of the speedo cable? not the transmission end? there is nothing that goes to the back of the cluster, does it connect to the ECM?

[Scott68-93-97]

speedo is electronic signal and theres a little motor that burns up that turns the odometer its easily replaced in the back of the cluster, this usually is caused by the tripometer freezing up putting drag on the odometer and frying the motor its actually common in the 88-94 trucks

[cabinetman]

Thanks for the help everyone. Now if you can tell me how to put more than 24hrs in a day I'll be set

[piecesparts]

Originally Posted by cabinetman

Thanks for the help everyone. Now if you can tell me how to put more than 24hrs in a day I'll be set

NOW ain't that the pits, we solve the guy's problems and now he thinks we are smart, too. Sheesh, you know that you will have to wait until daylight saving time to get more time.