A/C button not light up on my 90' 240sx

[nismo1003]

i have a US spec (KA24E) 90' 240sx , the A/C never been working since I purchsed the car , I am trying to fix it , I read up the 200sx FSM online and did a search on here, but I haven't find any thing yet. the problem is that the A/C button never light up, according to 200SX(Ca18Det)FSM A/C wiring digram for the A/C botton is that , it goes to the dual pressure switch . so does that mean that if there are no R12 in the system , it won't kick in? On my 98 Altima it light up even though it didn't have any R134 in it. by the way, can anyone send me a wiring digram for the A/C for my 90 240sx Ka24E? Thanx in advance.

[s13sr20chris]

wish i had that year fsm. i can tell you that the light not being on means you have a signal prob. try jumping the two terminals that are close together at the a/c relay.

[nismo1003]

thanx for the reply, I need to know where 's the relay at? is it bulid in to the a/c control unit? what's that relay goes to?

[NISTECH]

it is the relay that feed your compressor power. It is located under the hood in one of the black boxes. Be extra carfull not to jump terminals one and 2 in the relay as you will fry its controller. the numbers are printed in the terminal area of the relay flip it over and look next to the terinals with a flash light. match where 1 and 2 go in the relay socket and be sure NOT to jump those 2. should be 3 and 5 your jumping. Typically when the light does not illuminate when its pushed it means the system does not have enough freon to operate(pressure in the system is to low) if you can find the pressure switch(typically located on the reciever/dryer) try jumping that then push your a/c button if it activates your low on freon and need to get it checked for leaks.

[nismo1003]

thanx so much, I know there are none freon in the system, and there's a leak at the low pressure hose, I will have to get it replace, beside that, i just want to make sure if the eletrical system work such as the pressure sensor, and mainly the compressor. Thanx so much for the help NIStech and Chris

[s13sr20chris]

yeah, nistechs disclaimer is important. i should remember to include that same disclaimer.

[nismo1003]

i connect the Dual pressure sensor wire together and I press the A/C button the led light up..now I'm just waiting for to see if I can get the compressor working and if I need to replace the dryer, what is the condition that I need to change out the dryer?

[ricebike]

the compressor may start working again if you

replace that leaking low side hose, check the amount of oil in the compressor, evacuate the system/to rid any remaining h2o & to test for leaks again, & recharge the a/c system...

[nismo1003]

thank!

[ricebike]

... if I need to replace the dryer, what is the condition that I need to change out the dryer?

I sorta want to know this as well; how long can the dessicant in the receiver-dryer lasts w/ a prolonged exposure to the atmosphere/water vapor???

Is he safe enough to keep a vaccuum for a bit longer than normal to draw out the water in the system or would he have to replace the dryer while replacing the other known failed components?

are you thinking about upgrading to r134A? then u might as well change it over as well as most of the seals (i think u have to change the oil to a different type as well)

[s13sr20chris]

i have heard that the dryer can fail as result of exposure to air/water but i have never seen it happen.