Lebaron Landau L4-153 2.5L SOHC Turbo VIN J FI (1990)
If vacuum drop is now within limits, proceed with the overall performance test. If vacuum drop is still in excess of 3/4 inch (-3 kPag), remove 7-port
connector from switch and seal port No. 6 with a finger to check source hose. Then remove prod from source line and insert it alternately into each
connector port except No. 6.
Note amount of vacuum drop below 8 inches (-27 kPag) after each actuator has operated. If vacuum test gauge comes back to 8 inches (-27 kPag) at
each of the 7 ports, the hoses and actuators are not leaking. The control switch is faulty and must be replaced. If excessive vacuum drop shows up at one
or more ports in connector block, isolate faulty hose or actuator.
Inspect hose connections to the actuator involved. Then test whether actuator or hose is at fault; use the test hose on the actuator involved.
A leak in a hose may be detected with vacuum test set by running the fingers along the hose and watching vacuum gauge reading. The line can be
repaired by cutting out the "leak" and inserting the line into a 1/8 inch (3 mm) inside diameter rubber hose.
A vacuum drop in excess of 3/4 inch (-3 kPag) below the 8 inches (-27 kPag) needed in this test will not interfere with the engine operation, other than
perhaps to cause a rough idle. It can, however, interfere with the proper operation of the air-conditioning and heating controls at high speeds and during
acceleration.
