Tech Area

Inaccurate Temp Gauge

Question: I own an '85 2.8L GT and my temp gauge appears to be functioning but displays incorrectly. When first starting the engine the needle rests in the middle of the thermometer icon; at normal operating temperature, the needle moves to bottom of the icon and pretty much stays there. On a hot day (95F+) the needle will move to about the 100 degree mark.

I've taken it the local GM service center and their diagnostics indicated that the gauge itself was functioning properly, hence it must be one of the sensors/sending units. Subsequently, they replaced every sensor, but the problem was not corrected.

Any suggestions?

Answer: Apparently the needle has slipped. This happens frequently since ALL Fieros are somewhat miswired. 12v is applied the instant the key is turned to start. This "buries" the needle and upon time rotates it on the stem.

Often, the needle can be removed and relocated on the stem for correct calibration. After that is done (super glue works), the miswiring can be corrected.

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