I know I’ve asked about the fuel gauge before but I just want to be sure my diagnosis is correct. I replaced the resistor on my 69 fuel gauge, with everything connected my gauge reads full. It does not read at the 3 o’clock like the Wilcox video/documents say, it reads at full. I have directly grounded the input connection at the gauge to the ground in the frame and even the battery with no change in the gauge reading. I have reviewed every Wilcox diagram, document, and video I could find along with searching the forums multiple times. At this point I believe my gauge is bad does anyone else agree? I have continuity on the input wire from the sending unit all the way to the gauge so I know there’s no break, besides I grounded with a jumper wire direct from the gauge to the battery. I have ohm readings on the sending unit fairly accurate to what I eye ball is in the tank. And I have power and ground to the gauge as I have the temp gauge connected and verified with meter. I have done everything to diagnose this as I can think of I just don’t want to throw money at it if the gauge isn’t the culprit. Thanks guys

 

If the fuel tank hole in the 69 is like my 68's then you should be able to take a coat hanger and move the float assembly up and down. If you cannot quite see then remove the top part of the assembly and you can wiggle it by hand. If you do that and you don't see a response then it could either be your gauge or assembly in the tank.
Worse comes to worse you can transfer your fuel to another vehicle and then when the tank is empty pull the sender assembly out and exercise it outside the tank. You can even clean the sliding contact once you have it out..... probably worth doing this before replacing the gauge since if something is wrong within the sender assembly you won't know even if you replace the gauge.
Doesn't cost anything but time.

 

Thanks for the reply I’m not sure that is the problem though as per the wilcox instructions I should be able to ground the input wire and get the gauge to respond by going to E. It doesn’t move at all

 

Rookie question....have you taken an ohm reading on the gauge terminals with a digital ohmeter? When i get home I'll take some readings on my gauge.

 

I have taken an ohm reading from the input contact on the gauge all the way back to the sending unit and have continuity. I have 90 ohms resistance across the resistor. And my gauge is not grounded nor is it over torqued to where I have continuity from the contacts touching the housing. My gauge is pegged at full it’s not past full at the rivet it’s just sitting at full and no matter how I try and ground the input wire I cannot get it to go to empty. So I’m assuming the gauge is bad. It just sucks cause I just bought a new resistor from Wilcox.

 

Sounds like you are only measuring the resistor on the back of the gauge and that you have 'infinite' resistance elsewhere. That would indicate a broken wire or connection with the rest of the circuit. If you have continuity between the gauge and the sending unit, all that is left is a missing ground connection. Have you verified that the other side of the sending unit has a good connection to chassis ground?

 

Thanks for sticking with me with 7T1 yea I’ve even jumped a ground directly to the contact on the gauge from the battery and still get no response.

 

The ground connection needs to be made between chassis and the sending unit. If the sending unit doesn't get grounded, you get no signal from it.

You should NOT find electrical ground at the gauge terminals. You should only have the resistance 'signal' from the sender line and 12vdc power on those two lugs. Grounding is done at the tank sending unit and on the gauge housing (from the bezel).

 

Ok thanks I’ll double check everything and see what happens. I appreciate the advice.

 

Hey guys not sure if anyone is interested but figured I’d follow up today. I ended up grabbing a fuel gauge from the local parts house and wired it up as soon as I hit the key Bam went right to a quarter tank which is what I got! So at least I know my old fuel gauge bought the farm so I just gotta order a new one. I guess I have an extra Wilcox 90 ohm resistor now.