I have the ATC in my 97 Grand. I like it, but then it hasn't given me any problems. Only thing with that one is the ABS light is on, and the shop says 600.00 for fixing it..
Ok, lets see....I sent the unit out to get the A/C fixed and a replacement instrument bezel put in because the speedo was toast. When it came back I noticed the outside temp was showing 'OC'. When you turn on the key, it shows -40 degrees and then quickly shifts over to 'OC'. Someone else on the list said it meant Open Circuit. I thought it was stuck on Zero Centigrade
First thing I did was buy a replacement sensor ($17.50). Of course I couldn't get my hand up between the grill and rad to get it out, so I resorted to sawing off the mounting tab. I replaced the sensor and remounted it down lower than original but in the same vertical. No joy in Jeep land..same thing.
The same person mentioned putting a <20K ohm resistor across the connectors going back to the console. This seemed like a great idea, until I tried to follow the wiring.
So I resorted to waiting for the FSM that I ordered a month ago. That is another story in itself.
So last night I got into the FSM and found the self diagnostic test (page 8C-7). Ran the test and it showed 'CCd' as the code, which indicates "the module is not receiving all the CCd messages required for operation." So I guess Open Circuit is still viable. The harness connector, same page, Fig. 3 shows pins2/3 as the CCD feed. Looking through the 113 wiring diagrams which have PLENTY of CCD lines, I found diagram 74 which shows the Oustide Ambient Temp sensor for a non-ATC unit. That leads me back to a connector <D41> which is under the dash.
So basically I'm looking at pulling the dash.
Sorry for the long narrative, but you asked...