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HOMESERVICE MANUALSDODGE AND RAM1990SHADOW ES, 2D HATCHBACK, 2.2 CREPAIR AND DIAGNOSIS (SINGLE PAGE)HEATING, VENTILATION & A/C (HVAC)HVAC CONTROL SYSTEMSHEATER SYSTEMTESTINGVACUUM CONTROL SYSTEM TESTPUSH BUTTON CONTROL
1990 Dodge and Ram Shadow ES, 2D Hatchback, 2.2 C

Push Button Control

1990 Dodge and Ram Shadow ES, 2D Hatchback, 2.2 CSECTION Push Button Control
  1. With 8 in. Hg applied and test probe blocked, disconnect engine vacuum source and insert vacuum tester probe in hose leading to control switch. Push "HEAT" button and watch vacuum gauge reading. Vacuum reading should drop until actuator has completed operation, and then return to 7 1/4-8 in. Hg. See Fig 1.
  2. Repeat test pushing "OFF", "BI-LEVEL", "DEFROST", and "HEAT" buttons, allowing time for actuators to operate and vacuum to stabilize. Vacuum will drop below 8 in. Hg after each operation. Maximum allowable drop is 3/4 in. Hg.
  3. By-pass vacuum reservoir (if equipped). In the event of more than 3/4 in. Hg drop, recheck tester for exactly 8 in. Hg reading. Inspect fit of 7-port hose connector plug on heater control switch.
    NOTE: Do not use lubricant on switch ports or holes in plug due to possible damage to vacuum valve in switch. A drop or two of clean water may be used on connector plug holes to aid in positioning plug on switch ports.
  4. If vacuum drop is now within limits, proceed to overall performance test. If vacuum drop still exceeds 3/4 in. Hg, remove 7-port connector from switch and seal port No. 3 with finger to block source hose. Insert vacuum source alternately into each connector hole except No. 3.
  5. If vacuum gauge returns to 8 in. Hg after each actuator has operated, control is leaking and must be replaced. If excessive vacuum drop occurs at one or more holes in connector block, isolate faulty hose or actuator. Vacuum drop in excess of 3/4 in. Hg would not significantly affect engine operation.
  6. Vacuum leaks could interfere with proper heating operation at high speeds and during acceleration. Repair leaks in vacuum lines by cutting out leaking section and pushing cut ends of tube into short section of 1/8" inside diameter rubber hose.
Fig 1: Vacuum Tube Assembly Testing
G17666Courtesy of CHRYSLER MOTORS.
RENDER: 1.0x

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