On my 1995 Chev C1500 truck, the a/c compressor won't come on unless I jump it. Any ideas what could cause this problem?

Try the solenoids that control the shifting. May need to replace them.

Fuel pump it's in the tank there good for that

2.0 lbs.

Jumping the switch is only recommended for very short periods of time to check the compressor itself. The problem with straight-wiring it is that the compressor will run all of the time. During normal operation, the compressor cycles on and off depending on the pressure inside the A/C system. If you run the compressor all of the time, you run a risk of causing substantial damage to your A/C system, your car, or even yourself. The compressor would be constantly pressurizing the system until something releases that pressure. It may be an A/C hose or it may cause something larger to explode under the tremendous pressure. Be very careful with the A/C system and get the advice of a licensed A/C technician.

Look under the dash on the passenger side. It should be near the firewall. Tan wire with a black tracer.

what kind do you replace it with? Cost?? if its a cheaper compressor that may be the problem, quality of the part

Try your coolant temp sender, if it's bad the computer thinks it's running cold all the time, therefor giving it more gas.

Probably have to replace the whole switch.

the control unit is no good.i had a similar situation with a 98 tracker,and installed a switch to give it a ground for the compressor relay that comes from the a/c computer module.
it works good and goes on and off with the a/c switch.

the only thing left unless you have a leak is the proportioning valve A soft pedal can also be caused by badly adjusted rear brakes but you shouldn't experience a pedal fade right to the floor with bad adjustment.