Fuel Gauge Sending Unit ?
Parts Nerd Extraordinaire
Joined: Sep 2010
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From: Western NY
Those stock gauges do not operate on an ohms/resistance model, but the King-Seeley protocol. These sending units supply a full 6V through the heater wire in the gauge in the form of a square wave with the duration of the "on" being the variable determining the gauge reading. The longer the duration, the more fuel in the tank. It is this full 6v of current which heats the bi-metallic strip in the stock gauge that causes the gauge to read via a small gear train.
The way to test things is to test the gauge independently first with a D cell battery. It should swing to the half way point. If the gauge is good, the sending unit should be replaced (provided wiring and a good grounding has been established).
The way to test things is to test the gauge independently first with a D cell battery. It should swing to the half way point. If the gauge is good, the sending unit should be replaced (provided wiring and a good grounding has been established).
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Hopsing69
1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks
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Mar 16, 2014 09:38 PM
