The drain tube from the evaporator is located on the passenger side extending only about 3/4" from the firewall. You can easily get to it from under the vehicle on a creeper. Roll under the vehicle just behind the right wheel and look up almost right under the suction accumulator, the black tank mounted on the firewall that gets cold and sweaty when the system is running. The drain tube is a black plastic tube that exits the firewall near the bottom of the wall. Take a shop vac and put the end of the hose up to the tube and suck out any debris, wont take but just a second to do this. I don't recommend blowing back up into the evaporator cabinet, as you will only push the debris back to eventually plug the outlet up again at a later date.
As for the hot floorboard, I would TRY looking for a vacuum tube leaking, allowing the damper to not fully move to the cooling position to allow only cold air to blow into the compartment. Look at it this way, when you do run the heat, you can divert the hot air to the floorboard with the selector switch on the dash. This is all contorlled by the vacuum system, so I would check the vacuum tubes and hoses in the engine compartment.
Now for the pressure readings, when the system is running, (and the engine needs to be revved up to, and maintain, about 1500rpm) so as to simulate moving down the highway, the pressures should be in the "range" of 170# + or - a bit on high side and between 25-30# on low side when fully charged. As the cabin cools down the suction pressure will drop accordingly and cyles the compressor "off" at about 25#. But a set of gauges needs to be used for this, don't guess.

 

Mine seems to do this too.. Overcharged is my guess as it raises temps 10-20 degrees on engine heat due to excess heat being drawn in through the rad thus decreasing the cooling ability being the air is heated up even more so.

Also can hear pressure let off on the high side when the compressor kicks on.. or when you turn off the system the pressure releases.

 

Thanks for the explanation. When I'm at my in-laws this weekend I'll try and vacuum the condensate drain tube out. Right now it's around 80+ psi on the low side at idle. I'm guess that's way too high. I haven't measured the high pressure side yet, I'll try to do that as well this weekend. I do quite a bit of driving between work and visiting friends/family on weekends so having a properly working A/C would be nice, especially since this has been a hot summer.

 

On those hand held cans of Freon those readings are not acurate at all you can not depend on the readings but 90 is way high and probabaly not the true reading in PSI


These readings are not my readings and not showing a good PSI for this truck the Blue is the low side gauge this gauge set is not the correct gauges for auto use.

 

They sell those gauges at NAPA or Advance I assume?

 

rent them new are $150

Oh and dont buy cheap ones not worth their weight in ****

 

Ambient temperature is simply the temperature of the air surrounding the car. The following automotive A/C chart outlines the proper pressure readings for a particular temperature range. For instance, if the ambient temperature (outdoor temperature) is 75°, the corresponding low side pressure should be between 35-45 psi and if needed the corresponding high side pressure would be between 150-170 psi.

These PSI readings are done with higher than idle engine rpm's use something like a credit card under the idle set point to keep the rpm's up you want to get the reading in a running condition not idle.

 

There was another post on this forum about this problem. That individual put a valve in the line to the heater and shuts it off in the summer. What happens is our heater is hot all the time and there is a door to divert the air around the heater when in a/c. Over time the door and gasket do not seal properly and when driving for a period of time hot air leaks through causing the a/c to not be as effective. Mine does the same thing after about a 1/2 hour of driving, so i am going to try the valve.

 

That would make sense, I didn't really think about that. It would make sense as to why it works for half an hour or so and then just gets worse. I'm still not sure that's the only problem. I'm concerned about the water on the floor and the pressure being to high, but the door seems like it could be a problem too.

 

It's a 2002. The doors are electric, not vacuum, but good thought.

Those pressures are good at 70 degrees. It varies by temp. Use 98's chart.

As to the valve, just bypass it with a hose for now and see what happens.