Dash Cluster Headache

[Taylor father son]

Ive been restoring a 79' F100 Custom for the last year or so and the last thing I really need to do is to fix the dash cluster. The Fuel and oil pressure gagues do not work, havent been able to take it out to test the Speedo. None of the backlights work either. The bulbs are good, I have a new sending unit and plug on the tank and I have a steady pulse showing on the test light on both ends and the oil gague. I cant figure out what's wrong. I'm thinking about just buying a new cluster. Any help on fixing it or where to get a cheap replacement would be appreciated. The numbers on the back of the cluster are
D8TF- 10848-CA
Will any cluster number work?
Thanks.

[sargentrs]

This is often the culprit if your gauges don't work http://dennis-carpenter.com/m/product.a ... AZ-10804-A

[Taylor father son]

I got a used cluster @ ebay. Put in another fuel sender that I checked by plugging in before installing it in tank which worked. Still doesn't work @ guage. The oil guage doesn't work, I checked power @ the sender on motor with test light, do have power there. My dad & I could really use some help. This is the last thing I need to do so I can get title & inspection. Been paying insurance on this truck & still not driving. Can We PLEASE GET HELP.
ARE WE PUTTING THIS ON THE RIGHT PLACE SO ALL THAT ARE ABLE TO HELP CAN. THANK U.
Sorry for the double post

[sargentrs]

First things first. The fuel sender actually works off of the ground, not hot. Grab a test lead, wire with alligator clips on the end, to test the gauge. Have the key off and pull the black rubber boot plug off of the sending unit, at the tank. Clip one end of the test lead to the inside of the rubber boot, being sure you're touching the metal plug inside. Clip the other end to a good ground on the frame or crossmember. Now, go inside the cab and turn the key on for a second. If the gauge pegs out full, your gauge is ok. Don't leave the key on more than a second or two or could burn out your gauge. If the gauge doesn't move, try sanding the paint off where you clipped the wire. If everything checks out on the ground test, then clip a wire to the neck of the sending unit where the fuel hose clamps. Clip the other end to a good ground and check your gauge again like before. The tank itself grounds to the frame through the straps that hold it in place. If the gauge checks out on the second test, you're not getting a good enough ground through your straps. Sometimes there's a metal clip on the sending unit neck with a wire that goes over to a screw/bolt in the frame. My '74 Dodge Dart had that kind of ground connection. As for oil pressure, just grab a $20 SunPro gauge at your parts store and hook it up with an adapter fitting where the original sender is and drive with it. Speaking of, have you replaced your oil pressure sending unit yet? It also works off of the ground. Perform the same test as with the fuel gauge, clipping the test lead on the end of the oil pressure sending up wire and then to a good ground. You're oil pressure gauge should peg out too. Remember, only have the key on for a second when testing. Same with the water temperature. Once you've verified that the gauges actually work, that points you in the direction of the real problem.

[sargentrs]

Btw, if you haven't already found it, we have a sister site for dentsides. Hasn't been up as long but accumulating some good information. Here's a link to the wiring diagrams available. http://www.fordification.net/tech/wiring.htm