What do I look for when none of gauges work on 1986 ford f250

Sounds like you might need to check that the ignition switch is working properly.

check to see if there is a small filter in the fitting before the carby . Normally there is a small brass gauge filter in that connection that blocks very quickly. Check that the float is not stuck in the bowl cavity and blocking off the fuel. Adjust the float level by removing the level plug on the side of the bowl ( brand new does not necessarily mean ready for immediate use as adjustments have to be made on the engine . Check and adjust the position of the idle mixture screws as they may be screwed too far in

What have you checked so far ?
It could be the gauge, the sending unit in the tank, or the tank switch if you have dual tanks.

DIST HARNESS BURNT TO BRAIN BOX, NEED COLOR DIAGRAM DIST ,WATER,OIL, BOX ON FENDER 86F2504X4 5.8 AUTO

check the fuses and fuse link wires by the battery pull the fuse link wire with your finger if it feels spongy or comes apart in your hand you need to replace it with a new fuse link wire

Wes, try checking your float in your tank, or check the sending unit.

It could only be a couple of things. First check the wires to the starter solenoid. There will be a positive cable from the battery to the relay. Then you will have two more wires that go to two terminals. Jump between the positive terminal and the starter terminal. It should crank over. Sounds like you already did this step. If it does not crank check your battery. If the battery is good and you have power to the relay then I would suspect the starter bendix is probably to blame. You can replace the bendix on the starter. If you still have no power you will need to start at the ignition switch. Hope this helps. Also the gas in the vehicles tank could be bad and causing it to not continue running. Sitting for a year with a fuel tank not full will allow condensation to occur in the fuel tank. Last but not least most fusible links are attached at the starter relay because this is where the main power distribution occures to the vehicles other systems

the sending unit could not have power or the fuse could be burnt out. Sometimes the sending unit does get stuck.

the ignition switch must be adjusted, it slides back and forth, did you check the adjustment? if not call me at home 925-459-0571

Repair your vehicle right away. Just click on the link I attached 2004 FORD F250 SERVICE REPAIR MANUAL