Manager Forum

Customer Complaint: Automatic Temperature Control is not lighting up - No way to turn on the heater. We checked power & ground to the connector pins, and voltage/resistance looked normal throughout, so we condemned the Temperature Control Assembly. Got another one, and it also does not power up. Power to the unit, but no power? Does this assembly require two power sources? Any ideas?

Napafix hasn't been much help, so I find myself at the mercy of those with more practical knowledge....any advice?


UPDATE: We replaced the unit with a second one, and it worked well. Well all else fails, I guess - you just assume the junk you bought is junk... Thanks for your input!

According to the diagram, you should have power on two circuits to the amplifier. Pink circuit 1 and Brown/White circuit 17. The amplifier is built into the BCM on this and does most of the work. The pushbutton unit on the dash is just that, buttons. The same circuit that feeds Pink 1 on the amplifier feeds Pink 3 on the button assembly. There are supposed to be diagnostics built into the amplifier. Do you have access to the BCM via a scan tool? I've never been there before, so not sure on that. How about a good ground? From what I can tell, the button assembly talks to the amplifier via some kind of communication buss. There are three wires between the two units.

have you checked all fuses? as ric said the module is more of a monitor, most controls are through pcm. i have seen times where stored codes have shut down the monitor, however i can't recall it blinding it. personally i've never had to reprogram a pcm on one of these. it's usually a bolt and go. i'm thinking wiring and another possibility that i've seen, not on this appication, was the resistor shorted internally and killed the system. the amp load to the monitor is so low that a minor short can kill it. see if the plug at the resistor has melted together. good luck.