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Trying to figure out the vacuum hoses for the heater switch on a 77. Having a hard time translating picture 1 to picture 2. . Any help greatly appreciated.
Last edited by bleverman; Dec 1, 2020 at 06:25 PM.
I can faintly see numbers long side the vacuum ports of the photo you posted.
Take an old toothbrush, soap and water and give it a scrub and dry, you should see them.
If the switch is a aftermarket it will likely not have the numbers.
Your selector arm is clocked incorrectly.
Cars with A/C and without A/C will be plumbed differently but uses the same switch.
Looks like your diagram is NON A/C.
The correct installed position of the switch for A/C cars is like my photo below. NON A/C rotate photo 180*
Looking at the diagram again YOUR selector switch arm clocking MAY be correct for NON A/C cars
Last edited by bmotojoe; Dec 1, 2020 at 07:33 PM.
Reason: Maybe the clocking is correct for NON A/C cars
Here is a new HVAC vacuum switch photo showing both A/C & NON A/C port and selector arm positions when installed.
You can see the switch body is rotated 180* on the NON A/C layout
Here are the directions I received with the hose kit. So, 1. Black 2. ? 3. Blue 4. Tan 5. Green. Which is exhaust??
#2 is exhaust and should remain open. The vacuum actuators are spring return so the vacuum need to exhaust someplace.
The Hot Water vacuum switch on the heater box has it's own exhaust port.
Heater Control Switch Help
Any help greatly appreciated.
