Need A/C help

[_TD]

New to the forums as I just bought an '04 Excursion PSD about a month ago with 109k miles on it. When I picked it up the A/C was working, but it wasn't very cold. I assumed it needed a charge and drove it home. Had it charged last week and it blew a little colder but nothing like it should after reading this forum for the past week. I just took it on a 500 mile trip and it just quit blowing cold air altogether, feels more like ambient temperature. Here is what I have checked...

• The clutch engages and disengages when I cycle the A/C, and it keeps running, no cycling on and off.
• The temp controls can change from dash to floor etc no problem.
• It has no problem blowing hot air when on defrost or temp is set high and going back to slightly cool when I put it back down to 60 degrees.
• I let it run for about 20 minutes in the driveway and while one of the lines going to the condenser is super hot (the top line) I don't see any lines sweating like I have read about. None are even close to "beer can cold".
• I didn't notice the fan running at all, but last night I drove 200 miles with ambient temperature at 72 and with all of that air coming through I didn't notice a difference in the temp at all, so I assume the fan isn't the issue.

I don't have a guage so I unfortunately can't give any pressure readings. I did take it back to the shop yesterday that did the charge thinking they screwed it up, but after having it on the machine for about 2 hours they said the refrigerant level wasn't the problem and they needed more time to figure it out. Unfortunately I had to leave town for the road trip and couldn't stay any longer.

Any thoughts on this one?

Thanks!

[eagledieselmedic]

Get your money back for the 2 hours! If they cannot check an A/C charge in less then 15 they are taking you to the cleaners.

1. The high pressure switch OR low pressure switch cold be bad. If the compressor clutch is engaging normally and staying engaged, not short cycling on and off, you can most likely rule these two out. Systems can be overcharged and the extra freon forms a slush in the system. Go to the local parts store and get a can of quick freon with a gauge on it. Do not puncture the can. Most are calibrated from between 20 to 60 psi and color coded for too high and too low. (quick and dirty way to check while on the road, may cost you about $20.00)

2. Orifice tube could be clogged, drier clogged. No easy way to check, sorry.

3. Since it is an 04 you may have an accumulation of crud on the evaporator coils. These are in the box under the hood next to the blower motor. It can be a pain but remove the blower and look up in there with a good light. Might need to clean with an old tooth brush some fresh water etc. I did one recently that would barely cool. It had a plastic shopping bag stuck in it. The reciept was from 2009!!! NO JOKE.

If no or little air is moving over the coils in that box no amount of charge in the world will help.