I have a 1992 Chevy C1500 W/T Cheyenne

Not sure I follow what your problem is, but in addition to servicing the starter and charging circuit as you have done, also look at the ignition circuit. If you are losing power to the dash then check bulkhead connectors or pass throughs, and that all grounds are present and intact. I find that lost grounds on older vehicles are the cause of many electrical problems.

Sorry sorry...The truck began running a little rough, losing power when driving. I used to work on my truck with my dad but now, I'm a bit stuck as he is no longer with us. I drove it home from work, went to the market and when I got home, it was still running. When my husband went to take my roommate to work, it just clicked. Nothing. Didn't turn over. Now, I had taken it to a mechanic who has worked on my family vehicles and he insisted it was the battery. Alright. So I went and got a new battery and put it in. Fired right up. Took it to the gas station, filled and took it home. That night, was going to the market and click. Nothing. Low power on the battery. Possibly alternator as it's been about four years since my father and I changed that out. So we changed out the alternator the next day. Still got a clicking noise when trying to start the truck. Starter. So we changed out the starter. Now she wants to turn over but she begin and then clicking. When I spoke of the ignition, I would turn the key and it would return to the run position but nothing on the dash lit up after starting. I would have to push in on the cover to get it to release and then everything in the dash would work. Heater, radio, gauges and the like. We've tried jumping the vehicle and using a battery charger but again, it just won't start. I've checked the negative ground and it seems fine. We changed out the motor about seven or eight years ago and it's a tight motor. No leaks or corrosion. I'm wondering if I need to change out the switch or the lock cylinder. We've checked all the other fuses. I think we spent, brother in law and myself, every possible fuse and the ignition coil. I'm stumped.

Have you checked the wire harness and batt cables thoroughly? How about cables running to starter, or try a voltage drop test to that (see pic). Be sure to check for corroded or missing grounds, as well. If you're convinced your not losing electrical power due to a faulty connection, then check the ignition switch. The ignition switch and ignition lock cylinder are two different things, you can change out the switch with little trouble, but the lock cylinder would require reprogramming the truck to accept new keys, and you don't want to do that unless absolutely necessary. The ignition switch can give you symptoms like yours. Google symptoms to see what I mean.

Here is a pic for voltage drop test:

Thanks. I'll keep you updated. As I said, I did check the cables and the leads down into the starter and they were fine that I could see. I'll have to have a mechanic check on it as I don't have a voltage meter. As it's a new starter, should not need to check this, should i?

Thank you for all your help and suggestions. I am pleased to report that my truck is now fixed and running again. I found the ground wire to be the problem.