12v to the fuel sending unit
 

So I think I may have screwed up. I installed a boyds tank in my truck, hooked up the fuel gauge to the fuel gauge spot on the fuse block. It worked great till I moved the wire to a 12v spot on the fuse block. Now the gauge seem stuck in the 3 o'clock position. Did I fry something? Gauge? Sending unit? I'm hoping it's an easy fix. Any help is appreciated. Thanks

Re: 12v to the fuel sending unit
 

You don't want to put 12 volts to the sending unit directly. You risk heating the resistor element in the tank and igniting the fuel vapors in the tank

Run the terminal on the fuse block to a good ground and watch the gauge with the key on it should go to empty. If it does it means that the wire to the tank sender has lost it's connection.

If it does nothing, check the cluster feed fuse in the FP.

Re: 12v to the fuel sending unit
 

Vettevet, thanks for the reply. I looked at it again last night. I moved the wire back to the fuel gauge position, The needle is at 3 o'clock position with the key off. Then I turn the key on, it moves a little but not to where it should be.
Knowing my luck, I fried the resistor in the brand new sending unit.

Re: 12v to the fuel sending unit
 

You can put an ohm meter on the sending unit terminal and the ground, and you should read between 0 - 90 ohms if it's good, If you have fried the resistor it will continue to read past full.

You should ground the fuel terminal on the fuse panel and watch the gauge go to empty, which will tell you that the gauge is working. You have to be sure that the tank and the sending unit flange is grounded to the truck for the gauge to read.