1991 gmc speedometer

[javelinsst]

I typed the title into the search and speedometer wouldn't come up?
I'm having an issue with mine,not working. Should there be power at the wire on the transmission? Mine doesn't have power there.

[ChevyTech]

The vehicle speed sensor produces voltage. It does not get voltage from the wiring harness.

Is the odometer logging miles?

Is the ECM storing a code 24 for a VSS problem?

Are the anti-lock brakes storing a trouble code for a VSS error?

Does the cruse control work?

If the VSS (Vehicle Speed Sensor) does not work the ECM will set a code 24, the anti-lock brakes will set a code, and the cruise control will not work.



The most common problem is a poor connection between the instrument panel and the dash connector.

[javelinsst]

Thanks for the quick and informative response. I checked the vss and it works , there are no codes, the odometer works as well as all the other gauges (sweep style) and no cruise control option. Can I check the speedometer on the cluster with it out somehow?

[javelinsst]

Originally Posted by javelinsst

Thanks for the quick and informative response. I checked the vss and it works , there are no codes, the odometer works as well as all the other gauges (sweep style) and no cruise control option. Can I check the speedometer on the cluster with it out somehow?

With the truck off the speedometer is sitting at 20 mph. It will move up slowly to about 50 mph and seem to stick there and only come down to 20 after I've stopped.

[ChevyTech]

It sounds like the speedometer in the cluster is bad.

1991 clusters are not interchangeable with other years without doing wiring modifications.

In 1992 the DRAC was moved outside the instrument panel.

Early 1991 had the moon style speedometer.

Some late model year 1991 trucks had the needle style gauges but no separate DRAC.

Off the top of my head, I don't know of any testing you can do to the speedometer itself.

[javelinsst]

So what's my best option at this point?

[ChevyTech]

Where I live instrument panels cost $15 at the U-Pull-It.

If you don't have any salvage yards close by, then I would ship it out for repair. For a little over $100 there are repairs that come with a warranty. I can't find the name of the online repair site a friend of mine used, and was very happy with. If I find it in one of my other computers, I will come back here and post it.