1999 Cadillac Deville problem with adjusting A/C hot/cold a

SANDAN123

MEMBER
1999 CADILLAC DEVILLE

Air Conditioning problem
1999 Cadillac Deville V8 Two Wheel Drive Automatic 111k miles

When I turn on the A/C the driver side blows warm to hot air and the passenger side blows cold air. An A/C service man said that it might be a module below the dashboard that regulates the doors which direct the airflow.
Do you have any ideas?
By the way, it is also a D'elegance model.

1 Reply

BMRFIXIT

MECHANIC
19,053 POSTS

Blend door mix motor

DUAL ZONE SWITCH DIAGNOSIS
NOTE:This test is for vehicles equipped with passenger temperature control panel located in passenger door.

Turn ignition switch to ON position. Set passenger temperature control panel to warmest position. Using a DVOM, backprobe and measure voltage between ground and A/C-heater programmer (ACM) connector terminal D13 (Dark Blue/White wire). If reading is 12 volts, go to next step. If reading is not 12 volts, go to step 8.
Set passenger temperature control panel to coldest position. Using a DVOM, backprobe to measure voltage between ground and ACM connector terminal D13 (Dark Blue/White wire). If reading is zero volts, go to next step. If reading is not zero volts, go to step 8.
Press and hold passenger temperature control button down. Using a DVOM, backprobe and measure voltage between ground and ACM connector terminal C16 (Dark Blue wire). If reading is zero volts, go to next step. If reading is not zero volts, go to step 9.
Release passenger temperature control button. Using a DVOM, backprobe and measure voltage between ground and ACM connector terminal C16 (Dark Blue wire). If reading is 12 volts, go to next step. If reading is not 12 volts, go to step 9.
Turn passenger temperature control off. Using a DVOM, backprobe and measure voltage between ground and ACM connector terminal D10 (Purple wire). If reading is 12 volts, go to next step. If reading is not 12 volts, go to step 10.
Turn passenger temperature control on. Using a DVOM, backprobe and measure voltage between ground and ACM connector terminal D10 (Purple Blue wire). If reading is less then 12 volts, go to next step. If reading is 12 volts or greater, go to step 10.
Check ACM connector terminal contact. If okay, replace ACM. Recheck dual zone mode operation.
Check for open or short in Dark Blue/White wire between ACM connector terminal D13 and passenger temperature control connector terminal No. 6. If circuit is okay, replace passenger temperature control panel. Recheck dual zone mode operation.
Check for open or short in Dark Blue wire between ACM connector terminal C16 and passenger temperature control connector terminal No. 8. If circuit is okay, replace passenger temperature control panel. Recheck dual zone mode operation.
Check for open or short in Purple wire between ACM connector terminal D10 and passenger temperature control connector terminal No. 5. If circuit is okay, replace passenger temperature control panel. Recheck dual zone mode operation.