I went crazy this last week or so chasing down why my headlights would not work..parking lights, turn lights, brake lights, rear tail lights work but not the headlights and when I did pull the headlight switch to turn on the headlights, my front parking light would not turn on.
So after pulling the dash, replacing the dimmer switch (was bordering broken anyways), staring at the wiring diagrams and checking bulkhead harnesses multiple times like I have OCD, I gave up and worked backwards and started at the headlight ground and found the groud wire was corrorded internally. Cut out the bad section and now I have headlights but no front parking lights.
This is where I should have stepped away. Another couple of evenings of trouble shooting, tracing wires and staring at the diagrams again, I gave up and went to the chevelle forum and did some searching. Turns out this is normal because the early years did not have the front parking lights turn on when the headlights were on.
Well at least I know all the lights work now.
John D said
Apr 28, 2011
Don't beat yourself up too badly... I had the same problem on my '64, but the reverse. I HAD parking lights in headlight mode, and changed the switch due to a bad dimmer. When I was done, I DIDN'T have parking lights....
As it turns out I had a later model "generic" replacement switch that failed, and installed the correct (no park lights) model on my repair!
If you want park lights in headlight mode, there's an easy mod to do on the headlight switch, involving a jumper wire to an un-used terminal/post on the headlight switch. Dig a little on TC and you'll find it.
Chris R said
Apr 28, 2011
You should have posted here John. 64-67 have always had no parking lights when headlights are on. I could have saved you some trouble with that real quick but you live and you learn. Now you have a pretty good idea of how the headlights work so if you need to diagnose a light again down the road. You know what to deal with.
Also, dash lights are also operated from the same fuse as the parking/tail lights. So if the fuse for your dash lights blows, you wont have any rear tails and parking lights either. Headlights will still work.
SShink said
Apr 28, 2011
The ONLY reason I know some GM cars of that vintage's park lights don't come on with the headlights is because I had a '67 Camaro in college that operated this way...
I went crazy this last week or so chasing down why my headlights would not work..parking lights, turn lights, brake lights, rear tail lights work but not the headlights and when I did pull the headlight switch to turn on the headlights, my front parking light would not turn on.
So after pulling the dash, replacing the dimmer switch (was bordering broken anyways), staring at the wiring diagrams and checking bulkhead harnesses multiple times like I have OCD, I gave up and worked backwards and started at the headlight ground and found the groud wire was corrorded internally. Cut out the bad section and now I have headlights
but no front parking lights. 
This is where I should have stepped away. Another couple of evenings of trouble shooting, tracing wires and staring at the diagrams again, I gave up and went to the chevelle forum and did some searching. Turns out this is normal because the early years did not have the front parking lights turn on when the headlights were on.
Well at least I know all the lights work now.
As it turns out I had a later model "generic" replacement switch that failed, and installed the correct (no park lights) model on my repair!
If you want park lights in headlight mode, there's an easy mod to do on the headlight switch, involving a jumper wire to an un-used terminal/post on the headlight switch. Dig a little on TC and you'll find it.
You should have posted here John. 64-67 have always had no parking lights when headlights are on. I could have saved you some trouble with that real quick but you live and you learn. Now you have a pretty good idea of how the headlights work so if you need to diagnose a light again down the road. You know what to deal with.
Also, dash lights are also operated from the same fuse as the parking/tail lights. So if the fuse for your dash lights blows, you wont have any rear tails and parking lights either. Headlights will still work.
The ONLY reason I know some GM cars of that vintage's park lights don't come on with the headlights is because I had a '67 Camaro in college that operated this way...