a/c nippon denso wiring diagram
 

hey im looking for the wiring diagram for nippon denso ac on a s4. im getting no power at the pressure switch, and it is open circuit at the compressor. also where is the relay or fuse for the ac. i saw a few threads saying it the room fuse? just want to be sure

Look in the online series four wiring manual.

I's jumper the two wire plug to the pressure switch and then see if the compressor pulls in or not. If it does, then there isn't enough freon in the system.

The A/C RELAY gets a gnd from the ECU to pull the a/c relay in and put power on the compressor clutch.

The pressure switch........................not sure, but I think the ECU puts a gnd on the wire, not power. Just from memory, not sure, not a guarantee. The pressure switch wires are b/t the logicon and ECU and that other switch in the attached jpg. The ECU tells the LOGICON that the pressure is good (continuity thru the switch contacts) and continuity thru that other switch in the jpg and if there is continuity then the logicon gets the signal and then the logicon outputs a gnd to the a/c relay which pulls in and passes power to the compressors single wire.

Personally I'd use the HEATING AND A/C section out of the SERIES FIVE manual because it's the same thing but a better fault finding section vs the series four half ass manual for a/c.

Thanks I will check it out in the morning, and update my results

turned out to be a blown relay and some how my pressure sensor randomly started working again :). Thanks for the help.