Speedo works, then doesn't work!

[Jack K]

The last few days, when I first start the car, the speedo in my ‘89 Carrera doesn't register - nothing ... zilch. Somewhere along the way - usually after abt 15 or 20 minutes, it starts to work just fine.

The following day, same story.

Any ideas of what could be wrong and how to fix?

Tx

[Bobboloo]

I assume that 89s' have electric speedos?

Anyway, it could just be a dirty connection. Either at the back of the speedo or where it hooks up to the sensor located at the...distributor? I'm guessing where the sensor would be because my car has a mechanical speedo so maybe someone else with an electric speedo can chime in on it's location.

That it starts to work after 15 or 20 seconds suggest that maybe its heat related. So you might check in the engine compartment first as opposed to the speedo.

What happens to electrical connectors over time is they corrode a little. When the parts heat up they swell a little and close the gap,that was created by corrosion, thereby completing the connection.

So to remedy just pull the connector off and clean it and replace. Use of some di-electric grease wouldn't hurt either.

Good Luck
Bobby

[Rod Walter]

Another possibility is that you have a failing speedometer sensor on the transmission. The part is around $50 - $60 and isn't terribly difficult to replace. The wiring disconnect is beneath the tunnel access cover behind the front seats and the sensor is mounted on the left side of the transmission near the axle shaft. The hardest part is reinstalling the rubber grommet where the wire passes though the body.

These sensors do tend to go bad and the symptom that you describe is exactly how a failing sensor begins to show itself.

[JDaniel]

Every now and then my speedo stops working. Usually when the car is cold. Interestingly enough a shift from 4th to 3rd, or 3rd to 4th brings it back to life. I've probably got a loose connection. Since this happens so infrequently It's always slipping my mind...