ambient air sensor

[rrobe99999]

I have a '95 240SX that I bought with an S14 SR20DET already swapped in. There are a few things that were not completed. The A/C only blows cold air, and the compressor does not cycle off. I cannot adjust the temp, and now I want hot air. I found the ambient air sensor behind the front grill. It reads as a short with my ohm meter. I took it out and heated it with a hair dryer, and did not get any different resistance. Is that good or bad? If I disconnect it, the A/C still runs the same. Is there a cabin temp sensor I should check out? TIA for any advice that will help me fit this problem.

[NISTECH]

is it manual or auto air? does it have a manual slide lever or dial for temp control?

[rrobe99999]

Its manual with sliders.

[NISTECH]

check your cable and air mix door for binding. ambient temp sensor will have nothing to do with inlet air temp if its not auto air.

[rrobe99999]

Thanks for the prompt replies. My last car had auto air, so I have a few questions about manual air that should get me through this problem. Does the compressor stay on all the time when the A/C button is on? Does coolant always cycle through the heater core inside the cabin? If these answers are yes, then it must be the air mix door as you suggested. The hot/cold slider is very easy to move, so it might not be hooked up to the cable. What is the easiest way to get to this? Do I have to remove the dash?

[NISTECH]

Thanks for the prompt replies. My last car had auto air, so I have a few questions about manual air that should get me through this problem. Does the compressor stay on all the time when the A/C button is on?

yes if the fan switch is in any position but off

Does coolant always cycle through the heater core inside the cabin? yes

If these answers are yes, then it must be the air mix door as you suggested. The hot/cold slider is very easy to move, so it might not be hooked up to the cable. What is the easiest way to get to this?Do I have to remove the dash?

no the dash stays in you should be able to see the cable from under the dash on the passenger side. operate the lever while looking toward the center under the dash. you should see a cable moving. that would be the cable if it is not disconnected at the box its at the control head which can be real fun to get out. check the bottm first see if thats it.

[rrobe99999]

I didn't find a cable, but I did see a rod connected to a spring loaded mechanism. This was pretty far back behind the center of the dash, and looked like it was part of the A/C. Its connected to at the bottom of one of the black A/C boxes. It seems like it could operate an air mix door inside the box. It did not move when I adjusted the temp control. Anyhow, I've nothing left to do but start taking this apart to figure out whats wrong. How so I get in there?

[NISTECH]

you should have 3 doors in there one for temp one for mode(def,dash,floor vent) and one for recirculation. the one you saw may have been one of the other 2 so try operating all three functions and see if the rod moves. to be sure its not one of the others.

[rrobe99999]

I've verified that this is the air mix door, and it won't move. All the other controls work fine. How do I get in there to fix it?

[NISTECH]

I will assume this is an actuator(electric motor) you will need to replace it most likely if its not moving and it is plugged in. should be held to the box by 2 or 3 screws. are the screws visable?

[rrobe99999]

fixed the problem. Thanks for steering me in the right direction. The air mix door motor is also connected to a cable that goes into the engine bay. This controls a valve that lets coolant into the heater core when the temp control is turned to heat. My engine harness was blocking this valve and causing the cable to restrict the opertion of the air mix motor. It only took about five min to reroute the engine harness away from the valve, but 3 hours to figure all of this out. I was able to see the air mix motor from the driver side and trace everything from there.