A/C P0656 CODE "replace fused battery supply/circuit" anyone "done" this one

[sandmanxx]

A/C P0656 CODE "replace fused battery supply/circuit" anyone "done" this one or PTC#1

Just wondering for my info if I need to do it!

Would like info form someone who has 'actually" done this..

Or the PTC#1 side if is a issue.

* 2004.5 truck * not a TPIM or whatever it's called truck

Thanks

 

[sag2]

Here is the wiring diagram that might make it easier to understand. The control side of the relay pins 85 and 86 are controlled by the ECM. Actually pin 85 should be hot with key on only. The ECM grounds pin 86 to close the contacts on the relay, pins 30 and 87. Pin 30 should be hot all the time. Pin 87 will only be hot when the relay works properly.

So this is what I would do. Jump battery voltage to pin 87 with the relay removed, the compressor clutch should click. If yes, the wiring to the clutch, the clutch, and the clutch ground are good.
Next check for voltage at pin 30 with the relay out. Yes, fuse 16 is good and the wiring inside the PDC is good.
Next check for voltage with the relay out at pin 85 with the key on. Good, the PTC and wiring inside the PDC is good.
Here is where it might get tricky. If you have no voltage key on at pin 85 normally you should be able to jump voltage to pin 85 with the relay installed, but if the PTC is blown, the ECM may be monitoring that and never ground pin 86. Also without a DRBIII to actuate the circuit it makes it harder to diagnose.


Wiring diagram View attachment 2004 AC Clutch Wiring.pdf

 

[sandmanxx]

Here is the wiring diagram that might make it easier to understand. The control side of the relay pins 85 and 86 are controlled by the ECM. Actually pin 85 should be hot with key on only. The ECM grounds pin 86 to close the contacts on the relay, pins 30 and 87. Pin 30 should be hot all the time. Pin 87 will only be hot when the relay works properly.

So this is what I would do. Jump battery voltage to pin 87 with the relay removed, the compressor clutch should click. If yes, the wiring to the clutch, the clutch, and the clutch ground are good.
Next check for voltage at pin 30 with the relay out. Yes, fuse 16 is good and the wiring inside the PDC is good.
Next check for voltage with the relay out at pin 85 with the key on. Good, the PTC and wiring inside the PDC is good.
Here is where it might get tricky. If you have no voltage key on at pin 85 normally you should be able to jump voltage to pin 85 with the relay installed, but if the PTC is blown, the ECM may be monitoring that and never ground pin 86. Also without a DRBIII to actuate the circuit it makes it harder to diagnose.


Wiring diagram View attachment 92615

Thanks - I should have waited to post this thread.. Pwong is helping me on the PTC#1 thread. Lets do this
I may copy your post over to that thread and please chime in with Mr Pwong.. I may close this thread.
I will post simple notes on that thread what I rechecked trmw.

PIN #30 (right now) I only get 12V with key off lol
PIN #87 does not jump from direct battery touch. Did isolate compressor and fire clutch (compressor is new lol )

I do have a smarty to see codes and clear them at least