A few questions for those w/ working AC

[wolfsburged]

Just got my AC conversion to R134 charged and working. Still some improvements to be made, and a few questions:

1. There is a thermocouple-type thing that is connected to the AC control panel which I assume is a temperature cutout to keep the evaporator from freezing. I have this clipped in with the capillary tube from the expansion valve on one of the hard lines. Is this the appropriate place for this, and if not where should it be and how should it be fixed in place?

2. Was there ever a factory AC on/off switch that fits a blank spot in the dash? I want to rig some sort of switch so that the AC does not run on various vent selections other than heat.

3. Anyone have something rigged to trip the high speed fan mode at high pressure or idle? Notice a significant cooling difference sitting stopped with just the normal constant-on low speed fan in AC mode. I have an aftermarket binary pressure switch in the lines, was thinking of using one of those trinary switches to trip the high speed fans, or possibly also putting a selector switch in the dash for fan override control of "HIGH - AUTO - LOW". Anyone with experience here?

4. Odd issue - was driving around with the blower fan on "4" for my first round of testing, then randomly lost this speed completely. I thought I blew the fan fuse, but realized that I still have speeds 1-3. This seems odd as it usually would be the opposite and indicate a resistor issue. I'm thinking a bad connection somewhere...

Anyway its cooling decently right now, I think I have some more performance to get out of the system with some more tweaking. Also think I may end up needing to add a little more freon. Also need to make up some new cardboard ducts around the condenser. When all done I will post up a long detailed post with a lot of "lessons learned".

[theman53]

I am of no help, but am looking forward to your write up.

[R.O.R-2.0]

high fan speed is controlled by a relay, both heater fan, and rad fan..

[Powjetta]

My AC is working, with a slow leak at the compressor pulley.  I have to charge it up about once a year for optimum cooling.  It really takes HP, the NA is slow normally and with AC on it is dog slow.  I generally turn it off for pulling hills.
1. My controls don't have a thermocouple thing attached to them at all.  The left side is the AC and the right side is non AC positions.
2. No factory on off, but mine is '86.  The AC runs in the defrost position as well as the left side.  I basically have two positions, dash vents and foot vents that is non AC.
3. I have not done this, I watch my volt meter and turn my system down when the rad fan starts to take too much juice - I have a dual fan that takes all the power at full blast.
4. Haven't had this issue but R.O.R sounds right.
hope this helps

[wolfsburged]

So to clarify on the thermocouple thing, here is a photo of how I have it set right now:


The "wire" comes from the actual AC control panel piece with the vacuum distributor, and then into view in this photo from the top left, there is a tight bend and it comes back from the right and is currently clipped onto the pipe along with the expansion valve capillary.

I want to say it is supposed to be stuck into the evaporator core, but I can't remember and if it is, how am I supposed to make sure it is in good contact? I want to say this is there to keep the evaporator core from freezing up.

Hopefully this week I will remember to grab one of our calibrated digital thermometers with a lead to do some temp testing at the core and at the vents.