Was crusing in my '69 today with the a/c on. Drove into my driveway and turned the a/c off and both headlights popped up. They won't go down now. The control under the steering wheel that should keep the lights up doesn't have any effect. Headlight switch turns lights on and off but headlights stay up .
The wiper door operates normally. Never had any trouble with headlights opening/closing before. Vacuum hoses were changed several years ago. Engine runs OK--doesn't seem to be a vacuum leak.
What, if any, connection would there be with the a/c and the headlights ??
I wish I could help, but I have to say, you've got a 69 427 w/AC and you're troubling us with your problems? Just kiddinng of course because I have 79 and would give just about anything for a 69 big block and the A/C just sweetens the pot!
The A/C, the wiper door and the headlights use vacuum to control different valves and actuators. The three systems are interconnected to a certain degree.
Sounds like your have a vacuum leak on the A/C control side which is affecting the headlight controls. Try isolating the A/C system to see if the headlights work properly.
You'll need to get a schematic particular for your year to see exactly where it 'tees' off from the rest.
there is a vacuum control that opens and closes various "gates" in the heat/ac system and chances are somewhere in the system (as previously mentioned) you are losing vacuum. you might want to check the check valve first. it is located approximately behind the distributor in the main line from the manifold vacuum source (along with the filter). you might be losing vacuum there if the lines appear ok and connected correctly.
as far as the "stuck up" lights, if you look up at the assembly from under the car, you will see that there is an adjustment bolt sticking downward in front of the clevis (the round piece attached to the end of the actuator arm) elbow. with the engine OFF, if you reach up and pull down on that bolt, you will "break" the elbow and the light assembly will pull down. just a word of warning, watch where you put your fingers when you do it. you're safe if all you grab is the bolt, but you can get pinched if you grab the assembly, etc.
hope that helps.
BTW welcome to CAC. i think you'll find it a great place to hang out. the folks here are more than happy to share whatever they know with others.
Found the problem ! Was a bad vacuum relay on the front end of the car that supplies vacuum to the headlights. Ordered a new one, changed it out and the headlights work again.
Can't complain about a part failing after 37 years.
My Corvette(s): 1968 Convertible - Candy Apple - 427/475+
Quote:
Originally Posted by EdRoh
Found the problem ! Was a bad vacuum relay on the front end of the car that supplies vacuum to the headlights. Ordered a new one, changed it out and the headlights work again.
Can't complain about a part failing after 37 years.
Thanks for ideas.
When is the last time you replaced the 'witch hat' off the actuators? That messed up my vacuum as well.
My Corvette(s): 1968 Convertible - Candy Apple - 427/475+
Sorry for the delay.
Its a rubber gasket that in the shape of a witches hat or road cone It slides over the actuator rod and around the actuator vacuum reservoir. Look for Part# HDL173 @ http://www.riksvet.com The have a good picture of it. Like most rubber components, they harden with age. This will cause you to loose your vacuum as it did mine.
Need help with headlights
Linear Mode
