I am working on a 93 4x4, WT1500 with 4.3, auto O/D.

4WD does not engage and there are no lights showing on the stick console.This truck has been sitting for 4+ years. was started, but not moved much. I know the 88-up 4x4's have trouble with a solenoid ,switches, and actuator but i never really got into em and not familiar with what is what down there.. Any pics of what i might need and pricing /advice on repairs/replacement parts would be apreciated. I can do most repairs here at home.

the A/c does not work. It's that time of year that AC makes a big difference in the sale so what are current prices for a conversion to whatever works now versus the R12?? I'm guessing R12 is near extinct so what kind of pricing am i looking at for a conversion. thanx , DAVID

After I had My 93 silverado converted to the new refrigerent I've had nothing but problems with different components failing. orifice-compressor-and every once in a while my system will just release all of its refrigerent. My problems my not be due to the conversion. This has been my experience with the AC. It has cost me alot of money and at this point I just don't use it anymore. My mechanic thinks he need to replace the part under the dash board now. I'm wondering if there is a pressure difference between the different refrigerents. also after the conversion the compressor constantly cycles which effects my idel. I hate the AC in this truck.

I'm wondering if there is a pressure difference between the different refrigerents.

Yes, there is, in a way. with 134a you will add less as it will operate at a higher pressure with the same amount of volume. General rule of thumb is 75%, but you still need a set of guages to set it correctly.

If the compressor is cycling too much, you are a little low.

For the 4wd problem... I would first check the vacuum actuator (it is under battery tray for S10s - not sure where on a fullsize) for tears, or leaks, and that the vacuum hose is connected... And, that the cable going to the diff is not siezed... that is a common problem on trucks that sit or are from a heavy road salt area.
If all is good there, then check the vacuum hose leading from the actuator to the switch on transfer case for cracks and dry rot.

well I found out there is a TLA(thermo linear actuator) and a switch. POSI-LOK makes a kit that will convert this to manual engagement. crossy