Another winking headlight question

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Nov 14, 2011 | 06:42 AM

CaseyJones

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Melting Slicks

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From: McGrady NC

St. Jude Donor '15-'16

Another winking headlight question

I recently replaced most of my headlight vacuum system and now have working lights. It's new from the dash to the relays and actuators, including all hoses and headlight switch. However, one headlight will partially raise and lower under acceleration occasionally but not consistently. I used the forum search and did as much troubleshooting as I could with my handy dandy vacuum pump and visually checking the system. Any other ideas? By the way, I'm still working on getting all the interior hvac system to work and might have a leak there if that would have a bearing on the problem. Thanks for your help.

Nov 14, 2011 | 06:57 AM

TedH

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Joined: Feb 1999

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From: Tampa Bay FL

Check the vacuum system connections. Any cracked connectors? I had a power brake booster connector that was cracked and I would drop vacuum. Dr Rebuild has most connectors that you would need. They get brittle with age. Even the pot metal 2 or 3-way vacuum fitting in the port on the intake, aft of the carb, cracked on my C3 and I got a good replacement from the good Dr. I found that replacing all of the vacuum hoses/fittings AND removing/bypassing the thermal sensors on the intake (they control/limit vacuum until the engine is warm) made an incredible difference and I have reliable vacuum signal now; 14 years and counting.

Nov 14, 2011 | 07:07 AM

CaseyJones

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Melting Slicks

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From: McGrady NC

St. Jude Donor '15-'16

I will definitely check all connections. All hoses and connectors are new, but I'll go back over it more carefully.

Nov 14, 2011 | 09:24 AM

C6DuffMan

Drifting

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From: Roseville CA

It sounds like the check valve to me. The system shouldn't lose vacuum under load.

Nov 14, 2011 | 11:10 AM

78IndyPace

Racer

Joined: Feb 2007

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From: Buena Vista Colorado

Quote:

Originally Posted by C6DuffMan

It sounds like the check valve to me. The system shouldn't lose vacuum under load.

Agree. Remove the check valve, put it to your lips and attempt to blow through it from the manifold side (single large port). If you can blow through it, it is defective.

Nov 14, 2011 | 11:54 AM

Peterbuilt

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From: mount holly NC

2025 c3 ('74-'82) of the Year Finalist - Unmodified

2019 C3 of Year Finalist (appearance mods)

Many times its the seal in the actuator that goes bad:

How to test:
http://www.corvette-101.com/vacuum.htm#actuator

Nov 14, 2011 | 03:35 PM

CaseyJones

Thread Starter

Melting Slicks

Joined: Jul 2010

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From: McGrady NC

St. Jude Donor '15-'16

New relays and actuators. New hoses. New filter. New check valve. New headlight switch. I'll check the valve just in case and make sure the hoses are all on tight. Otherwise, I'm out of ideas. By the way, the headlight that winks also opens the quickest. Go figure. Thanks for the suggestions so far.

Nov 15, 2011 | 12:23 AM

Peterbuilt

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From: mount holly NC

2025 c3 ('74-'82) of the Year Finalist - Unmodified

2019 C3 of Year Finalist (appearance mods)

Seems like everything on the vacuum side is new and if each component tests good then you might want to see if you have 4 springs and that all the pivot points more freely.