First of all my 1955 ford went down the road fine and passed inspection with no problems but the fuel gauge was reading full and I put 25.00 worth of gas in it and temperature read hot but it was not over heating and the radiator felt normal not excessive hot.

Rod,

Yep, It was a simple very basic drawing to illustrate only.  You're absolutely correct, as my 55 is wired as you say.

In each case, the actual 'second wire' is vehicle chassis ground.

In the case of the original question in this thread, with both guages at their 'top', there is probably a problem with power getting to the guages from the ignition switch; had it been only one problematic guage (especially the fuel guage), I would suspect the ground connection (engine temp. sender would be difficult to imagine having 'lost' its ground; but, fuel tank sending unit losing ground is quite common - either between the tank and chassis, or between the sending unit and tank itself).

Thanks,   JLB

55 Ford Crown Victoria Steel Top