Ranger 4WD V6-183 3.0L (1993)
Thermostatic Air Cleaner Vacuum Switch: Testing and Inspection
Testing 2 And 4-Port Regulator Valves
2-Port Vacuum Check
Applying vacuum to Port A, while the engine and sensor are cold, should produce the OPPOSITE results, at Port B, as to when the engine and sensor are
warmed and vacuum is applied.
4-Port Vacuum Check
The 4-Port valve is equal to two separate 2-Port valves that share the same thermal sensor.
Applying vacuum to Port A1 and A2, while the engine and sensor are cold, should produce the OPPOSITE results, at Port B1 and B2, as to when the
engine and sensor are warmed and vacuum is applied.
Switching Temperature for 2 & 4-Port Control Valves
Color Code
Closed Below
Open Above
Brown or Black
80~F (27~C)
95~F (35~C)
Green or Blue
103~F (39~C)
128~F (53~C)
Yellow
135~F (57~C)
160~F (71~C)
Natural
70~F (21~C)
85~F (29~C)
Gray
125~F (52~C)
150~F (66~C)
3-Port Vacuum Check
Testing 3-Port Regulator Valves
1.
With cold engine, vacuum applied to Port A (center port) should leak from Port C (upper port).
Vacuum should NOT leak from Port B, if Port C is plugged with finger.
2.
With warm engine, vacuum applied to Port A (center port) should leak from Port B (lower port).
Vacuum should NOT leak from Port C, if Port B is plugged with finger.
3-Port Electrical/Vacuum Check