I've got a problem with my A/C that I can't figure out. I keep blowing my "Elec Parts" 10A fuse in the driver kick-panel (bottom left fuse). At first I thought I was having the dreaded Radio issue, but the head unit checks out fine after taking it to a repair shop.

After looking at the schematics, the Elec Parts fuse connects to the climate controls above the radio, the compass, and digital readout above the clock, and to the A/C compressor.

If I disconnect the head unit, the fuse still blows. The digital readout above the clock has a blown (black, burned out) chip on it, but it DOES NOT blow the fuse while connected no matter what buttons/settings I use on the climate control. I assume that this may be collateral damage from the main issue.

The problem appears to be with the compressor. If I disconnect the green/yellow connector on the bottom of the A/C compressor, the fuse does not blow.

So I guess the question is... Is there something attached to / within the compressor that can be replaced without replacing the compressor? Is there some relay/switch between the climate control and compressor that I can check/replace?

It's a 2004 so I'm not in the mood to spend a thousand bucks on a compressor...

Thanks in advance,

John

 

I think this is a bit of an easier question to help me along. On the compressor, there are 2 connectors. One on the side and is black (for power). The other is on the bottom and is Green/Yellow. The Green/Yellow is the one that I've disconnected. How do I test the wiring? Should there be a voltage across the Green/Yellow? Should there be continuity? If so, only when the A/C switch on the climate control is on? If these test bad, then at least it may not be the compressor but something between the climate control / compressor / fuse / battery.

Any help would be appreciated.

 

The service manual is called atc.pdf and can be found here:
http://www.nicoclub.com/FSM/G35/Sedan/2004/

With patients you should be able to trace it but it's a bit convoluted. Here's an excerpt from that manual:

When A/C switch, AUTO.ECON switch or DEF switch is pressed, display and A/C auto amp. inputs compressor ON signal to BCM.
BCM sends compressor ON signal to ECM, via CAN communication line.
ECM judges whether compressor can be turned ON, based on each sensor status (refrigerant-pressure sensor signal, throttle angle, etc.). If it judges compressor can be turned ON, it sends compressor ON signal to IPDM E/R, via CAN communication line.
Upon receipt of compressor ON signal from ECM, IPDM E/R turns air conditioner relay ON to operate compressor.
When sending compressor ON signal to IPDM E/R via CAN communication line, ECM simultaneously sends compressor feedback signal to meter control unit via CAN communication line.
Meter control unit sends compressor feedback signal to display and A/C auto amp. Display and A/C auto amp, then, uses input compressor feedback signal to control air inlet.

So the magnetic clutch (blue/orange wire) comes from a relay in the IPDM, but only if the all the related sensors agree it's OK to turn it on... Hope this helps...