Odd wiring behind dash in 98 TJ

Found the wire in the diagram F12-20-RD/LG. So I'll have to find it tomorrow and test for voltage when engine is running. If there is voltage when engine is running and there is also continuity between ground and C1 (C13-18-DB/OR) from a back probe at the same time then I'm going to be really stumped.

Screen Shot 2021-02-25 at 7.03.35 PM.png
 
Christoph said:
Found the wire in the diagram F12-20-RD/LG. So I'll have to find it tomorrow and test for voltage when engine is running. If there is voltage when engine is running and there is also continuity between ground and C1 (C13-18-DB/OR) from a back probe at the same time then I'm going to be really stumped.

View attachment 229233
Click to expand...
You said before that there was voltage there, the F12-20-RD/LG is connected to B8 which is the socket you circled in blue and had 13V.
 
I know the relay itself works for sure. And I know the PDC can give power to the contractors because the jumper works. So it's gotta be ground not coming from the PCM right?
 
I have continuity between Pin 1 of PCM and B8 of compressor clutch relay but no ground. There is continuity between B8 and positive terminal of battery but not negative terminal of battery. This is with both HP and LP switches jumped just to rule them out.

This is back probing with grey PCM plug inserted, vehicle running, AC on.
 
Going to resurrect this one more time in hopes that someone sees/knows something I don't.

I know for sure that pin one of PCM is not sending ground to relay cavity 85. I crammed a wire in cavity 85 along with the relay itself and started everything up, jumped wire to black terminal of battery to give it ground and the compressor clutch engaged.

The issue is definitely on the highlighted side of this circuit. Everything highlighted has also been tested and confirmed to have continuity. I have also bypassed both HP and LP switches so I can rule them out. That leaves me with two things. Bad PCM or bad AC Heater Control.

Does anyone know how I can bypass the A/C heater control here so I can rule it out?

I know this thread is getting dragged out but I really don't want to give up and hire a mechanic to figure it out just yet. My pride won't let me.

IMG_0972.jpeg



IMG_0973.jpeg

Screen Shot 2021-02-28 at 1.41.18 PM.png
 
Last edited:
Top Bottom
Back