Good morning everyone! This last week I've starting experiencing some troublesome electrical problems in my 73' f250. I went to start it one day and had zero power to anything, no lights, no clicks from relays, not the even the electric fuel pump starts (key on power). I poked around didn't find anything obvious but had errands to run, later that day got home to find my lights on (left them on earlier), truck started and ran no problem for a day or two afterwards. When I tried to start it 2 days ago it was back to zero power anywhere. I did some more in depth poking checking for corroded/ loose wires with no luck.
So far I have:
- Replaced battery as the old one had a crack near the + terminal and was under warenty
- Replaced starter solinoid, I've had the truck for 13 years and its never been replaced
- Repaired a frayed wire on the ignition switch
- Checked fuses
- Checked and cleaned battery cable connections, cables do appear to be in good condition with solid connections.

Today I'm going to start poking around with a multi meter to see if I can find where I'm losing power. The alternator does look a little worse for wear and I have a new one on hand. To be honest the harness itself is kind of a mess and has been spliced into in multiple places before I got the truck I'm considering getting a new harness but that seems like an extreme solution to what could be a simple problem.

 

Welcome to FTE. I suggest you continue on with the meter. Otherwise, you are just "pulling in the dark". That truck would not have had an electric fuel pump as OE. The electrical ignition system on that truck, if stock, is about as simple as ever made. A patched wiring system does not sound good. A meter is invaluable to troubleshoot. Make certain the alternator belt is not slipping.

 

having a meter is a good idea and will save time... even the cheap $6 one at harbor freight will do what you need here, but 90% (completely made that number up) of electrical problems on old vehicles are ground related... the ground strap from the battery to the block, the block to the frame, the frame to the body, or at the device you are powering and a meter could show you having power at all these places but without a complete circuit, you still have no lights, no start, no fuel pump sound (unless you've changed it you wouldn't because it should be mechanical.) or anything else you mentioned.

with it being all these things at once and sporadic, after you make sure your battery terminals are tight, i'd start with the main ground straps.

 

Update:
-Replaced block to firewall ground
-Replaced battery cables just in case
-checked ignition coil for proper resistance

The only change I have found so far is suddenly the key on power circuit for the electric fuel pump and electric choke is hot with no power going to anything else i.e. no lights, starter does not engage when the key is in the start position.
The choke and fuel pump have been installed the same way on the same circuit for years with no issues whatsoever.

Could this be an indicator that my ignition switch is faulty?? I have not checked the starter motor or alternator yet.

Edit: Pulled the connector to the ignition switch and hooked the fuel pump back up circuit is still hot, so not the ignition switch

 

where is your fuel pump and/or choke circuit drawing power from? any relays added?
can you elaborate on "Repaired a frayed wire on the ignition switch"? is it possible something got shorted to power there?

with the ignition switch off (or completely disconnected), you should have headlights/horn/hazard flashes, so see if any of those work when you experience the totally dead scenario...

 

Assuming you have a power draw, the best way I have found to find it is:
-Measure voltage at the battery.
-Start pulling fuses until you see the voltage jump up.
-That is the system that is drawing power. Follow up and fix.

Short version, but you get the idea.