I have a 1980 yota longbed 4x4 the fuel gauge doesnt work. I tested to see if there is power at the plug on top of the tank with a test light. What could the problem be? the float is stuck? sending unit?

 

Well what did the test tell you? Was there power? Could be the gauge, could be the sending unit.

 

sorry there was power.

 

I'm pretty sure the factory service manual describes a way to test the actual gauge, but I'm not sure what it is off the top of my head. If you can find another cluster, you can always just try swapping a different fuel guage into your cluster and see if that works.

Maybe somebody here who's run into this before will speak up.

 

there was power coming into the plug and power going out so I think the gauge is ok I kinda think the float is stuck, but im not for sure. And where the heck would I find a float/sending unit for a 1980 toyota?

 

I'll bet the dealership would have it, or a junkyard, or a site like this.

Although it seems to me that if there's power at the sending unit, but the guage isn't showing anything, it would be the gauge that isn't working..

 

the gauge moves alittle up to the empty mark when the power is turned on.

 

Most fuel senders are grounded and do not us a positive wire going to them. they are basically a rheostat (think volume control) and read the resistance (ohms) from the gauge to ground. you can test the gauge by grounding the sender wire (working your way back from the gauge to sender). to test the sender use a ohm meter and raise the float up and down the numbers should slowly go up and down. If there is no resistance or it jumps erratically the sender is bad. Toyota may be different but I don't think so. I don't remember.

 

Refried is right.

If you got power at the sender, your probably testing the wrong wire.

Test the gauge by running a jumper from ground to the signal wire on the back of the gauge cluster (look at the circuit board you can figure out which is which) If the gauge goes to FULL, then the gauge is OK. Run a jumper from your sender directly to the signal wire on the gague cluster. If it works OK, you have a wiring issue. If it still doesnt work, your sender is bad. I've had many floats become saturated with fuel and loose boyancy, thus sinking in the tank and not giving true readings.