A/c Problems

[95_Nissan_240sx_s14]

I live in florida so maybe someone can help me get my a/c working. Normally i don't need any help when it comes to fixing anything on my motor but the a/c system stumps me. I have a 95 Nissan 240sx and i THINK i have an electrical problem. when i start my car and turn on my a/c i get no compressor. i can manually turn on the compressor by pulling out the relay and hooking it up to the positive battery terminal. I fill up the a/c and everything works fine. It blows cold and i have no problems. I figured it to be the relay but i've found that to be not true. I've traced the wires that come from the compressor to the fuse box under the hood but that couldn't be the problem because when i hook it up to power i get the compressor powered up, so i only can assume that somewhere between that fuse box and the control panel up front, that i could POSSIBLY have a short unless there's another relay that i might have missed? Also, the wire comes to the compressor, it branches off and goes to a sensor underneath the car. Looks like i would guess to be a free-on detector sensor. Can anyone help me. I would kinda like to get my a/c working again. It worked when i bought the car but quit 2 weeks after and i had it refilled but can't get the thing to work correctly. Its a KA motor also just for clarificationThanksAaron

[95_Nissan_240sx_s14]

Anyone?

[Brandon93240]

The sensor is a pressure sensor, with the car running and a/c on jump that sensor and see if you compressor kicks on, if so your pressure sensor is bad.

[95_Nissan_240sx_s14]

The sensor is a pressure sensor, with the car running and a/c on jump that sensor and see if you compressor kicks on, if so your pressure sensor is bad.

I jumpered that sensor and my compressor didn't come on so i'm guessing that it is something else..I'm stumped. I've tried everything that i can possibly think of without changing the interface inside the car. I guess thats next.

[Brandon93240]

Do you have a test light, if so with the car on trigger the a/c with the relay out, put your test light on the spade that gets the signal from the hvac control and let me know if you have power or not. By the way if you don't know what terminal to probe give me the year of your car and I can tell you which one it is.

[2000nisfrontier]

I have a 2000 nissan frontier and I have similar problems. My air conditioner will work somtimes and not other times. I have recently found out that it is the THERMAL CONTROL AMPLIFIER. It is located behing the glove box on my vehicle. This may or may not be the cause of your problem but you may want to check this out.

[Brandon93240]

Yes this is always a likely problem with nissans. Its a thermistor, based off of the sensors reading it will cylce the compressor off and on. Even when they are bad they will usually let the compressor kick on when first intiated but will cut the compressor off quickly, sometimes you can kick the evap case and if the compressor kicks off and on it needs a new thermistor.

[don m]

I too am having an a/c problem.my a/c compressor clutch only energizes when the radiator cooling fans come on,and de-energizes when the fans go off.HELP!!!!

[lindelc]

I have a 2002 Frontier V6 automatic with 74000 miles and had intermittent AC problems after replacing the AC compressor and bad high pressure hose. The AC would work fine for short periods of time then nothing. Living in Florida, I needed to find a fix for my AC problem. The solution was hard to find. But I had to replace the thermal control amplifier (http://www.nissanparts.cc/cart/?pn=27675-92000) which is located in the wiring harness behind the glove box. Part costs about $30 and it took about 15 minutes to install it. Now my AC works great.

[nissanfrontier2000]

same truck......same problem.............but I just relaced the whole unit in the dash and still nothing.....I don't know whats next?? maybe the thermal contl. unit?

[ghx407]

I don't know if this helps but I'll post it anyways...

I understand that 240SXs have a refrigerant gas pressure sensor. If the sensor detects low refrigerant pressure in the AC system it won't let the compressor work in order to protect it from lack of lubrication (refrigerant doubles as an AC system lubricant). The problem might therefore be that you have a refrigerant gas leak and when its pressure drops, the car "kills" the compressor to protect it from seizing.