Chrysler Repair: Auto Heat/air control-1996 Chrysler Concorde LX, 1996 chrysler concorde, check fuse

Question
Heat/air controls totally malfunction.  All control lights & temp read out go off, but blower---blows hot air.  Unable to even turn system off.  Replaced control head and ignition switch, but to no avail.   What is going on?

Answer
Hi Phil,
There are two fuses that you should verify to begin with. In the box behind the end cap on the left end of the dash check fuse 6 (10 amp) and that powers the control panel. Then there is a fusible wire link in the brown wire that is coupled with a white wire in a separate harness that is attached to the + post of the battery and those two wires go to a 4-pin disconnect along the left frame rail nearby where you can open up the disconnect and use an ohmmeter to verify that the fusible link is conduction (i.e. not blown out). That circuit powers the rear heated window.
Let me know if both of those current paths to the control panel are good and we'll go from there. The path from the fusible goes to pin 1 of the green plug at the control so another way would be to verify that it is showing 12V all the time.
The fuse 6 output goes to pin 5 of the black plug and it should show 12V when the ignition is 'on'. Pins 2 and 6 of that same plug should be grounded (show 0 ohm resistance to any structural metal surface nearby). Once you show all that is good, we can consider what else might be wrong.
Roland