A/C - Mode Change While Accelerating

84chrysler3

Models


1983 400; 1983-1984 Reliant, Aries, LeBaron, Town & Country, 600 & New Yorker; 1984 Executive Sedan, 600 ES, Daytona & Laser (All Engines)


Subject


Mode Changing on A/C Unit During Vehicle Acceleration


Index

AIR CONDITIONING

Date

3-19-84

No..


24-02-84

P-1134
SYMPTOM/CONDITION

Air conditioning mode changes on vehicle acceleration or when driving uphill can usually be divided into one of two categories:

(1) Mode shifts when in Max A/C, A/C, or Bi-Level. Major causes of this problem include vacuum extension harness improperly connected to either the push button switch or the A/C unit vacuum harness, vacuum hose not connected to the actuator properly, or connected properly but hose leaking (cracked or split), or defective check valve.

(2) Mode shifts when in Max A/C or A/C, but not when in Bi-Level. Major causes of this problem include vacuum hose not connected to the actuator properly, or connected properly but hose leaking (cracked or split), or lower diaphragm (shaft side) of the 3-position mode actuator leaking.

Before proceeding, be sure all connections are made properly.

DIAGNOSIS

Check Valve Test PN 3441609

1. Remove A/C control from the instrument panel and disconnect the 7-port female connector of the vacuum extension harness from the push button switch.

FIGURE 1:

2. Connect a vacuum gauge to port #3 (black hose) of the 7-port female connector (Figure 1).

3. Start the engine. Depress and release the accelerator pedal 4 or 5 times, or until the vacuum gauge indicates 15" Hg. or higher.

4. Stop the engine. If the vacuum gauge reading drops, the problem is either a leaking check valve or a leak in the black vacuum source hose. Repair as required and retest.

FIGURE 2:

Three-Position Mode Actuator Test PN 3847849

1. Using a "T", install the vacuum gauge between ports #3 (black hose) and #5 (brown hose) as shown in Figure 2. Start the engine. Depress and release the accelerator pedal 4 or 5 times, or until the vacuum gauge indicates 15" Hg. or higher. This will apply manifold vacuum (black hose) to the side port of the mode actuator (brown hose).
2. Stop the engine. If the vacuum gauge reading drops, remove the brown hose connector from the side port of the mode actuator and plug the hose at the connector.

3. Start the engine. Depress and release the accelerator pedal 4 or 5 times, or until the vacuum gauge indicates 15" Hg. or higher.

4. Stop the engine. If the vacuum gauge reading drops, repair the leak in the brown vacuum hose and retest.

5. If the vacuum gauge reading remains the same, this indicates a leaking lower diaphragm (shaft side) in the mode actuator.

PARTS REQUIRED

1 - Three-Position Mode Actuator PN 3847849
1 - Vacuum Restrictor Assembly PN 4342205

REPAIR PROCEDURE

1. Remove and replace mode actuator using procedure outlined in appropriate service manual.

FIGURE 3:

2. Install restrictor assembly as shown in Figure 3.

3. Test system for proper operation.
POLICY: Reimbursable within the provisions of the warranty

TIME ALLOWANCE:
Labor Operation No. 24-50-47-90 Restrictor 0.2 Hrs.
24-65-12-90 Actuator 0.8 Hrs.

FAILURE CODE: X9 - Vacuum Leak