2004 Nissan Titan A/C does not work

Question

My A/C quit working and I have checked the following. All fuses are good, freon level is good. Was told the low pressure sensor/switch was bad so I replaced it...no change. Thought a relay may be bad in the IPDM-ER so swapped it out(entire IPDM-ER)...no change. There is a pin on connector 119 in the IPDM-ER (Pin 11/Yellow/Black wire) that if you apply 12V to it, the A/C works fine. Dissasembled the intrument panel to get to the back of the control switch and it does switch when depressed (although it doesn't latch)...so thought about holding button in, and compressor still does not engage. My thoughts...one of three things...the voltage from the back of the switch is not getting to the ECM...the ECM is bad or the switch is bad. Any help or ideas would be greatly appreciated. Right now I have wired in a toggle switch that applies 12V to pin 11, Plug 119 in the IPDM-ER just so I can have air and not roast in this SC heat.

Answer 1

Pin 11 is the wire direct to the A/C compressor, from the A/C relay. What activates the A/C relay is the Body Control Module (BCM), but the signal is send via Control Are Network (CAN) not a voltage signal. You need an special scanner to read if the the BCM is sending the signal to the IPDM via CAN. You should be careful checking the wires without the proper instruments becuase you may damage the entire CAN system.

Comments

woulThank you.  Is the A/C relay something that can be replaced?  If so where is it located?  I was thinking it was integrated into the IPDM-ER circuit board.  Guess I will have to take it to dealer to have them put a scanner on it.  My usual repair shop used their scanner, but probably not as in depth as the dealer I would presume.  Thanks again.