Headlight vacuum troubleshooting
Thread Starter
Burning Brakes
Joined: Oct 2000
Posts: 877
Likes: 59
From: Minneapolis, MN USA
Headlight vacuum troubleshooting
Hi all,
I have a 1970 small block. When I go to turn on my headlights, one of the lights (driver side) seems to take 5-30 seconds to pop up, and the passenger side really never does. It might get half of the way up after a minute or two....unless I am driving at a good speed, then they seem to pop up much quicker. They don't seem to struggle as much to go down.
I'm wondering if there is a good document out there that could step me through the system and how to check each component to try and figure out what is going on? Pictures would be good too as I have a lot to learn and don't know what each component is called.
Any help would be appreciated.
I have a 1970 small block. When I go to turn on my headlights, one of the lights (driver side) seems to take 5-30 seconds to pop up, and the passenger side really never does. It might get half of the way up after a minute or two....unless I am driving at a good speed, then they seem to pop up much quicker. They don't seem to struggle as much to go down.
I'm wondering if there is a good document out there that could step me through the system and how to check each component to try and figure out what is going on? Pictures would be good too as I have a lot to learn and don't know what each component is called.
Any help would be appreciated.
Le Mans Master
Joined: Aug 2006
Posts: 7,419
Likes: 1,554
From: mount holly NC
2025 c3 ('74-'82) of the Year Finalist - Unmodified
2019 C3 of Year Finalist (appearance mods)
Does this help?
Many times the seal (grommet) in the actuator goes bad.
Here's a HOW TO so you can test each component.
http://www.corvette-101.com/vacuum.htm
Willcox has a HOW TO that covers the wiper door parts if you need it.
Here's a HOW TO so you can test each component.
http://www.corvette-101.com/vacuum.htm
Willcox has a HOW TO that covers the wiper door parts if you need it.
Melting Slicks
Joined: Apr 2007
Posts: 3,189
Likes: 111
From: Tolland CT
I found all 3 vacuum relays leaking on my 70, one very badly. Replaced all three. Headlights pop right up now. The relays are easy to test with a hand held vacuum pump. Actuators can be tested as well.
