fuel gauge test

[quickster]

Hey all, is there any way to test the fuel gauge to see if it works without pulling the cluster? On the '87 the needle is pinned above full for both tanks. No movement when switched. I know the mid tank is not full. Fuses are good all around. Probably something easy, but I never had to do a fix like this. Any help is much appreciated.

 

[ifrythings]

Usually pegged past full is an open circuit condition, this can happen if the full switching valve messes up or if both sending units wear out, that’s what happened with my 87 is both senders wore out.

This is the resistor piece in the sender that wears out, you can see the missing contact area in the sweep range.

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They do get dirty over time also

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[dgr]

• Ford up to 1986 - 73-10 Ohms
• Ford 1987 & up - 16-158 Ohms

Open circuit on an 87+ will peg the gauge. Open circuit on 86- will show empty.

The gauge moves when you turn the key on so you have power to it. Two wire plug at the sending unit. There should be some voltage on the colored wire for the tank you're switched to. Disconnect it and jumper across them. The gauge should drop to empty. If it does, your sending units are bad. If it does not, there is an open circuit between the gauge and the tanks or the ground wire isn't grounded. Next candidate is the tank selector valve.

 

[quickster]

Thanks guys. Will look at it Monday.

 

[Clb]

@Colton Stevens

 

[Clb]

Bump