Speedometer Diagnostic

Tracking an intermittent connection in an electronic speedometer can be a hit or miss affair if each time you think you have it fixed it needs to be buttoned up and test driven. Jacking up a wheel and running the car in drive is an option, but using a common household item will make the testing of the gauge safer and easier.

Get the wall transformer hooked up and put the key in KP-II for a test. Mine just happened to be working at the time.

Pull the cluster out and set it on top of the steering wheel. My suspect is the L-shaped plug, because when I touch that, the needle dives to zero and the odometer stops ticking.

The gauge can be removed from the cluster and tested by itself, if a jumper is connected to provide power around the flex fuse on the cluster circuit board. ABS gauges from 92-93 have four terminals here instead of three, so the jumper needs to go on the innermost two.

Here's how I fixed my particular problem. The gauge wire's terminal was not squeezing the circuit board edge connector well. This wire is blue from 86-89 and green/white 90-93.

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