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73-87 Chevy _ GMC Trucks => Interior & Equipment => Topic started by: 79K20 on March 30, 2009, 11:21:47 am
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Hey all.
Just trying to diagnose why my temp gauge quit working. Its a '79 K20 w/ 350 eng. I believe it is a vacuum-type temp sensor, right?
Anybody know how these things work? Is there an easy way to test the sensor and the gauge separately to see which is malfunctioning?
Thanks.
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No, it's a thermistor. Take the wire off of the sending unit screwed into the drivers side head and ground it with the key on. See if the gauge moves.
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I thought the sending unit was on the thermostat housing...?
That blue thing with the four vacuum lines coming out of it...?
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Should be on the left side head behind the first spark plug
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That's just a thermostatic vacuum switching valve.
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A What-Ditty-What? Here it comes... What on Earth does a Thermostatic Vacuum Switching Valve do?
Haven't had a chance to ground that sensor wire out. Will do it later today and see if the gauge works....
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When temp goes up it allows vaccum to pass through.