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My 71 drivers side headlight door keeps opening upon start up then when I shut car down it will open then eventually close. Very annoying! Here is where I'm at so far: New actuators, relays, vacum hose kit, check valve, white filter, wiper relay, wiper door valve, wiped door actuator re sleeved with new seal, headlight switch. Vacuume tank passes pressure test. I've also retested the new components and they are holding pressure. Obviously pressure must be leaking from somewhere, but why only 1 headlight. Don't know where to go from here. Any help? Thanks.
Perhaps because each headlight has it's own vacuum supply and relay.
On start up the 'servo side' of the system (actuator and it's vacuum supply) are receiving full vacuum and opening the headlight door before the 'control side' of the system (the relay and it's vacuum supply) signals the door to stay closed. Once the relay receives sufficient vacuum it signals the door to close, and it does.
I'd look for a relay that's leaking or a leak in the small control hoses.
Sounds like a bad relay. I would move the new relays you have and switch sides. See if the problem moves. (I had a vac problem a few years ago. After I replaced actuator seals, check valve, tubes ... I still had a leak. Traced it to a brand new check valve problem.)
Sounds like a bad relay. I would move the new relays you have and switch sides. See if the problem moves. (I had a vac problem a few years ago. After I replaced actuator seals, check valve, tubes ... I still had a leak. Traced it to a brand new check valve problem.)
I actually tried that. I left relays in place mounted but just reversed the hoses and now the problem was on the passenger side of the car as opposed to the drivers side. So the leak has to be some where in the drivers side.
If only one headlight is doing this the problem is the relay or the signal to the relay on that side. If they both were doing the same thing you would have to troubleshoot the whole system. Since only one is doing it, it's either that relay or the actuator but the actuator works as the headlight does come up. The only other thing is if you have the two vacuum hoses from the relay to the actuator reversed as you say it opens right on start up when it should be vacuum powering to the closed side of the actuator. You said it is opening on start up but didn't say if it is momentary then closes or stays open. If it stays open you have the hoses reversed. If it is momentary, it's the relay. You can confirm it by switching the two relays and see if the problem moves to the other side. There have been problems with some after market relays in that it takes more vacuum to signal the relay to move the inside relay valve to the closed position than it does to activate the actuator causing a momentary rise. Same problem with momentary wiper door rise on start up as they use the exact same relay there.
Last edited by CanadaGrant; Aug 5, 2017 at 12:34 AM.
I will reverse relays as Billk80 and Canadagrant have suggested. Hopefully I can get to this today. I have tried this test early on only to have the problem move form drivers side to the passenger side. Which tells me it's not the relay. Hose from relays to actuators not crossed. As Alan 71 suggested...test small control hoses that go from over ride switch to relays again. Just to re clarify issue.....drivers side headlight opens on start up is momentary. Then when car begins running it will close. When car shut down headlight opens slightly then eventually closes in about 30 seconds. Thanks all! I will report back.
Ok. Here's where I'm at now... I pressurized the small white stripped line that goes from top of relays to the headlight interrupt switch. All hold pressure. As CanadaGrant and Bill80 stated. I then removed both relays (as opposed to just reversing hoses) and took drivers side headlight relay (the problem side) and installed in passenger side and passenger relay now installed on drivers side. Well now problem show on passenger side. So I would now say it's definatly the relay. Can these relays be rebuilt ir fixed?
Yes they can, I have rebuilt many. I only work on GM relays however.
When it comes to relays or vacuum problems Dave is your man.
Some of the aftermarket relays are made with the wrong spring along with other poor production problems. With no vacuum the relay is in the command "open" position. Normally it takes less vacuum to overcome the small internal spring and put the relay in the command closed position than it does to move the actuator so the headlight (or wiper) door stays closed. If the spring is too strong due to poor aftermarket tolerances or there is binding caused by debris or wear in the internal valve in the relay you will get a momentary opening of the door.
Time for a new relay or contact Dave.
Last edited by CanadaGrant; Aug 6, 2017 at 12:38 AM.
So I decided to take the relay in question apart. But prior to that I read in another CF post that spring tension on aftermarket relays are higher than the OEM relays, causing this pop up condition. So being that relay is defunct I carefully remove the retaining ring and removed spring. Just as an experiment I cut away 1 full circle of the spring. I replace all back together and installed back in car. Upon start up headlight came up as usual. Shut car down and only popped up a bit. So removed relay again and cut another 1/2 circle spring away. The replaced all back, restarted car and no more headlight pop up. Shut down car and headlight didn't come up either. I'm not sure if this classifies as a Bubba fix but if it continues to work I don't have to purchase another pesky relay. FYI all.
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Another Headlight Vacum Issue
