Fuel Selector Issues.

[hesutton]

Hey guys. My project truck is having issues with switching between the front and rear tank. The issue is.........it will not change from the front tank to the rear. Does anyone know how to test the in cab switch and the valve on the frame rail? Also, my new front sender is way off. It is reading more fuel than is in the tank. Any ideas on that problem too?

Thanks boys and girls.

Heath

 

[argve]

The OEM fuel tank switching valve is a motorized valve - it runs on 12v (naturally) all the switch does on the dash is reverse the polarity to the motor. So the easiest way to see if it's working is to hook up a voltmeter to the two outbound wires and see if the polarity flips...

 

[F350camper]

well, here is my best attempt at being Pete....

http://home.comcast.net/~robert.fox2/fsv.htm

 

[Agnem]

Correct. Pins 1 and 2 of the 5 pin plug are where the motor voltage goes. You can easily bench test the valve by applying 12 volts to these pins, and then reversing them. You should hear the valve move, and you can see it move through the ports. There are diodes inside the valve, which if they go bad, can prevent the valve from returning to the opposite position.