�Vacuum
Actuated Headlamp Doors�
1969 RPO Z22
Brief History:
All three years of the first generation Camaro were available with the RPO Z22 �Rally Sport� option. Any Camaro could be ordered with the desirable hidden headlights starting with the most modest inline 6 cylinder right on up the food chain to the powerful COPO. In 1967 the headlight doors were opened and closed by electric motors, which Chevrolet quickly replaced with a vacuum actuated system in 1968. I do not know if the 1968 system was revised in 1969. This means if you have a 68 RS Camaro use this information cautiously and have the correct year manuals referenced below to be sure...
Reference Material:
The Vacuum actuated headlight doors are just one of the features included on the 1969 (RPO Z22) Rally Sport Camaro. The intent of this tech feature is to aid you in understanding how this very simple vacuum circuitry is plumbed and works. Please reference the 1969 Camaro Factory Assembly Instruction Manual� (AIM) RPO Z22 B6 (page 462) for part numbers and proper installation of hardware and routing of hoses.
The diagram I have included has been laid out in a way that depicts proper connections of hoses and components based on the AIM and will give you a feel for where everything belongs. They are not intended to show mounting and proper physical placement. For additional reference, the 1969 Chevrolet Chassis Service Manual (CSM) also has information that may be of assistance to you (Section 12: Electrical-Body and Chassis: Lighting Systems starting on page 12-6 Vacuum Operated Headlamp Service�).
Getting Started:
Take a good look at the diagram; let's start with the vacuum source. You will find a vacuum line running from a fitting on the intake manifold across the firewall toward the driver side fender (the black hoses on the diagram).
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Click Here to open diagram in a new window.
Note: Hoses are black or black with colored stripes and are as depicted in the AIM. These colors concur with the CSM with the exception of one of the black hoses, which is shown with a white stripe. I chose to default to the AIM for correctness as the CSM represents several of the Chevrolet line up with hidden headlights.
With the engine running, the headlights off and the override switch in the normal position there will be vacuum present on the black hoses, the yellow-striped hoses, the Vacuum Tank and the middle port of the Vacuum Relay. You will also find vacuum present through the headlight switch and on the orange-striped hose from the headlight switch to the Vacuum Relay and the green-striped hoses to the actuators. The doors will be closed under these conditions.
Take note of the one way check valve or "Vacuum Line Filter" (much like the one used in the power brake booster system) placed in the main vacuum line coming from the intake manifold. It keeps the system (black, orange, yellow and green-striped hoses) holding about 10" of vacuum when the engine is shut off. That is based on what I measured on my own system. At this point there is no vacuum present on the red-striped hoses.
The Operation:
The headlight doors operate (open) when the headlight switch is pulled out to the second position (headlights on) cutting off the vacuum to the orange-striped hose. This operates the Vacuum Relay removing vacuum from the green-striped hoses and placing vacuum on the red-striped hoses to the actuators. This can also be accomplished by operating the over ride switch (pushing in the plunger) which plugs the orange-striped hose, removing vacuum at that point (same result as turning on the headlights).
Testing:
To test the system, start the engine and push the override plunger switch in on the Vacuum Relay, the doors should open. Pull out the plunger on the override and the doors should close. Do the same from the headlight switch. If they don't open and close properly, or at all, make sure the mechanical parts of the doors are adjusted and working smoothly before tearing into the plumbing.
Assuming the mechanical parts all function properly you now know where vacuum should be under open and closed conditions. Trouble shoot by unplugging one hose at a time and verifying that vacuum is present or not. Reproduction actuators have had a bad rap in the past so you might want to start there. Verify the switches (Headlight and Vacuum Relay) are doing what they are supposed to as well. Hose kits have been known to have the ends get brittle and crack before they even get taken out of the box they are packed in so be alert for vacuum leaks too. If low idle vacuum is a concern, vacuum should increase with rpm so set your idle up a bit if you have to for testing.
End Results:
It's a great feeling knowing your headlight doors open and close properly, it's the little pleasures in life, isn't it? Special thanks go out to Team Members Chad Renfro (CA420) and Todd Bradford (DTB) whose research and willingness to share their knowledge with TC has assisted me greatly with this tech reference page. Thanks guys! YOU ARE NOT JUST BUYING PARTS – YOU ARE GETTING OUR CAMARO EXPERTISE
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