1993 Volvo 850 climate control device

TTUFFIN

MEMBER
1993 VOLVO 850

Heater problem
1993 Volvo 850 Front Wheel Drive Automatic 150000 miles

My 5 cylinder Volvo 850 GLT has no control of cabin temperature. There is no control of the damper doors directing the airflow. Is the A/C programmer broken and can it be repaired?

1 Reply

KHLOW2008

MECHANIC
41,814 POSTS

Hi ttuffin,

Here is a description of the temperature controls and how to retrieve Diagnostic Trouble Codes.

SELF-DIAGNOSTICS
The Electronic Climate Control (ECC) control module can detect faults in the system and store Diagnostic Trouble Codes (DTC). If a fault is present, system informs driver by flashing the LEDs by the AC and REC switches for 20 seconds. A fault warning is given when a fault is discovered or present, each time ignition is turned on, or engine started. DTCs will remain stored until cleared by an input code.

NOTE: Test Unit (981 3190) and Adapter (981 3194) are required for DTC diagnosis. The Volvo Diagnostic Key (998 8670) may be used to perform self-diagnostics. Follow tool manufacturer's instructions.

There are 3 different test modes/settings which can be selected for reading off DTCs. TEST MODE 1 may be used for reading off DTCs detected by control unit (up to 47 codes can be stored). TEST MODE 2 checks signals from speedometer and solar sensor.

TEST MODE 4 is used to check electrical circuits in A/C system, reset information on damper motor limit positions and change data transmission speed from ECC control module to on-board diagnostic unit.

NOTE: Ignition must be turned off before switching from one test mode to another.

ENTERING SELF-DIAGNOSTICS
1. Connect selector cable from diagnostic unit "A" to terminal No. 1 of diagnostic unit "B", located behind right headlight. See Fig. 2 .

2. Turn ignition on. LED on diagnostic unit "A" should start flashing. Each DTC (3-digits) consists of a series of flashes with a short break between each series. DTCs are displayed in ascending order.

TEST MODE 1
1. Turn ignition on. Press button on diagnostic unit "A" for about one second. Read LED flashes.

2. If LED flashes DTC 1-1-1, no faults are stored. If LED flashes other than DTC 1-1-1, display DTCs and perform appropriate DTC trouble shooting.

TEST MODE 2
1. Turn ignition on. Press button on diagnostic unit "A" twice (for about one second each time). LED should start flashing rapidly once TEST MODE 2 is activated.

2. If LED flashes DTC 1-1-2, signal from solar sensor is okay. If LED flashes DTC 1-1-3, signal from speedometer is okay. If neither DTC is present, go to next step.

3. If DTC 1-1-2 is not present, check solar sensor. If DTC 1-1-3 is not present, check speed sensor signal. To exit TEST MODE 2, turn ignition off.

TEST MODE 4
1. Turn ignition on. Press button on diagnostic unit "A" 4 times (for about one second each time). LED should illuminate. If LED illuminates, go to next step.

2. Control codes must be entered one step at a time. See TEST MODE 4 CONTROL CODES . LED should go off after each digit is entered. Entering each digit in a code must be made within 4 seconds as failure to do so will abort input and TEST MODE 4 must be restarted.