Headlight winkie question

There is a loss of vacuum somewhere in the system.   By design, the headlight relays will default to the "open" position if there is a loss of vacuum to them.  Troubleshooting procedures for this would require going through the system with a vacuum gauge to locate the leak.  If there are any original vacuum lines in the system, they may be brittle and leaking when exposed to the cold temperatures. proracr38700.6286226852

Trouble found!  One of my GM Mechanic buddies found it..  On one of the new hoses when is got cold it contracted and didnt seal somewhere.  When warm it snugged up.  I'll worry about it at the first oil change!  THANK YOU ALL FOR YOUR HELP!  

Thanks proracr,

  Just shows how much this forum can work. I never heard of the line leaking when cold. I ended up putting tie-raps on some of mine. Thanks again.

Im with Gellis, whodathunkit?

Thanks for the feedback.  The vacuum operated headlight doors and wiper doors can be a pain at times, but they aren't that difficult to troubleshoot and repair if you understand the systems and their components.

Proracr, is your guide more detailed than the one Doc Rebuild puts out? I'm having some issues with mine, not quite ready to start on them yet, I've put all new lines on but haven't even started checking relays.

My troubleshooting guide first explains how the systems work step-by-step, then walks you through the troubleshooting procedures.  Once you fully understand the systems and components, the troubleshooting is a lot easier.  All you need to troubleshoot the headlight/wiper door vacuum systems is knowledge, patience and a vacuum gauge.  The '71 Vette that I just purchased is going to to be a "research platform" so I can revise and expand the troubleshooting guide.