AC efficiency issue

[mgold]

My car was converted a few years go to R-134, but has worked well until about a year or so ago.  Here's the issue.  When its cool out (low 70's or cooler) or when driving at highway speeds the AC blows ice cold.  At idle or bumper to bumper traffic the AC blows cool, but not cold.  I've checked the system and it appears to have a full charge.  The aux fan does kick on when I turn the AC on.  I suspect that its supposed to kick on to a higher speed, but I'm not sure how to check for that.  I've been told that its likely the switch or the resistor or possibly even the fan clutch.  Thoughts or suggestions are appreciated.

On a side note, I checked out realoem.com and they show 3 similar parts called a temperature switch from two different locations and I'm not sure if any of those are applicable.  The first one is 61311378073 which is labeled part #10 here and the others are 61311364272 and 61311364273 which is part #6 here.  The second switch appears to be part of the aux fan assembly while the other is part of the radiator.

[D. Clay]

My car does the same thing. I can put a big shop fan in front of the car and it blows cooler. I am going to try wiring without the resistor. Just send 12v direct to the fan motor. A bad fan clutch will not pull enough air.
There are a lot of people that say their A/C works great. I am of the opinion that E30 A/C's are barely adequate. Of course, I live in central Texas. Without a windshield shade it gets so hot you can't touch the wheel.

[Wise Old Dog]

The aux fan is a 2 speed unit. The a/c switch powers the low speed side. If you remove the resistor, you will make it a 1 speed. More noise, shorter fan life, maybe better engine cooling.
I also think that the e30 a/c system is barely adaquate with the r12, much less with the 134. I removed my system.

[mgold]

okay, so if the AC system engages the low-speed, what sensor kicks it up to high-speed?  How can I tell if the resistor is bad?

[Wise Old Dog]

There is a 3 prong temp switch on the radiator passenger side. This controls both speeds. Remove the wire connection and jump the connectors inside to turn on low or high speed. If the fan works on hi speed but not lo speed, you have a faulty resistor.

[mgold]

thanks, I'll give it a try sometime.  I assume if it works fine then its the temp switch.