I have a '95 Blazer LT 4X4, 4.3 L. After replacing my heater core (fun job....not), I put the gauge assembly back in and my speedometer and odometer quit working. They are traditional gauges (not digital), but they are all electrically operated. On the back of the gauge set is a flexible plastic membrane with a printed circuit. All of the other gauges (tachometer, water temp., oil pressure, fuel, volts) appear to be working properly. Just thought I'd see if there is anyone with some suggestions before I tear back into it and sit there scratching my head.

Thanks.

You are going to have to get back into it and see what, if anything, is amiss.

Thanks swartlkk, I figured that would be the case. I have never seen the flexible printed circuit like that. I tried not to disturb it when I removed the gauges. Do you know, are they really fragile?

They should not be fragile, but if it got snagged on something, it could pull it loose from its connection.

Thanks. If that did happen is there a home fix I can do or is it going to have to be replaced? I wasn't rough with it but in hindsight, after finding out what was back there, I could have been a little more careful.

I took the gauge cluster out and nothing looks wrong. Can anyone tell me how the speedometer works on 1995 Blazer? It appears to be completely electrical--there is no mechanical connection for the speedo or the odometer.

Does anyone know anything about the flexible circuit boards that supplies power to the gauge set? If something goes worng with them can they be repaired or replaced separate from the gauge cluster?

Many thanks.

The VSS (vehicle speed sensor) feeds speed information to the PCM or ECU/DRAC module (depending on your engine control configuration). From there, the signal is sent to the gauge cluster along with many of the other gauge displays.

You should try pulling the electrical connections and making sure that the flexible circuit board contacts are all fully seated into the socket.

Thanks for the information. I really appreciate it. I have already removed the gauges and looked closely at the socekt where the connection is made and it appears to be engaging fine. All of the other gauges (oil pressure, temp, volts, tach, and fuel) are working fine. How do I tell what kind of computer I have in my Blazer.

Thanks

Just an update. I was able to identify the problem. On the male half of the connection I found one contact that was bent. I have poor eyesight and had to use a magnifying glass to find it. Once I bent it back in shape, the speedometer was up and running.

Thanks for the help.