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I just replaced all the headlight vaccum hoses on my 73 vette because the headlights weren’t popping up at all and I thought Mabye that was why, it did nothing they still are down and if I try and put them up manually I can’t it feels like someone is forcing the headlights down so when I try and push them up they slam down right away like there’s a lot of down force.
And what’s weird is I don’t have a manual switch to open and close my headlights because there isn’t one looks like a previous owner just by passed it and took it out I have no clue why
You should notice 2 sets of springs up in there. one set holds em down, the other up. if you reach up from under the car and push on the pivot, you should feel some spring resistance until you pass the half way up point. then the up springs will take over and pull them up the rest of the way. Do not try to pull on the doors from the top. Do this with the car off. see how you go.
push here for up.
Last edited by 4-vettes; Aug 29, 2021 at 03:35 AM.
headlight relays have mud wasp nests in them. that crescent shaped hole is where the air has to go in to push the headlight up when the vacuum removes the air from the other side. these are a pair i bought on ebay. the 2 in my car had the same nests in them. down does not use this passage so they drop just fine. it is just up that suffers.
Last edited by derekderek; Aug 29, 2021 at 06:58 AM.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
do you have the hoses in correctly?. You can open the hood and remove the small diameter black hose with the white stripe from the small nipple on the metal diaphragm cap. It is what controls the plunger to change the vacuum. If that doesnt work pull the center hose adn see if you have vacuum. Replace it and see if either of the other 2 hoses have vacuum. Then when you pull the black hose it should switch
All the over ride does is vent the vacuum hose to that top nipple by the way
Last edited by Rescue Rogers; Aug 29, 2021 at 08:35 AM.
since OP can't pull them up, it is definitely the vent blocked in the relay. as he pulls the light up, he is creating a vacuum in the actuator can since air can not enter through the bug nest. sometimes you hold it up and air will slowly bleed in and eventually stay up. but this is a free and easy fix. crawl under car with a 1/8 or 3/16ths drill bit. stick bit in the crescent shaped hole. spin bit. if you take the top of the 3 big hoses off, the lights will both pull up and work with vacuum. that vent connects to the top vacuum hose when the relay valve is down to let atmospheric pressure in. this is what the missing air filter on the bottom of the relays is supposed to protect from.
since OP can't pull them up, it is definitely the vent blocked in the relay. as he pulls the light up, he is creating a vacuum in the actuator can since air can not enter through the bug nest. sometimes you hold it up and air will slowly bleed in and eventually stay up. but this is a free and easy fix. crawl under car with a 1/8 or 3/16ths drill bit. stick bit in the crescent shaped hole. spin bit. if you take the top of the 3 big hoses off, the lights will both pull up and work with vacuum. that vent connects to the top vacuum hose when the relay valve is down to let atmospheric pressure in. this is what the missing air filter on the bottom of the relays is supposed to protect from.
- stick the bit in crescent shaped hole do you mean on of the three holes on the actuator valve? If so the top hole the middle hole or the bottom hole?
look at pic i posted. you can see the crescent shaped hole on the very bottom with the mud in it. the round thing with the pin in it is the actual vacuum valve. the vent hole is right next to it. better pic. when valve is down, put a hose on the top big hose nipple and it should blow thru that crescent. when valve is up, vacuum goes to that side and the lower big hose vents right out the bottom.
Last edited by derekderek; Aug 30, 2021 at 06:39 AM.
when there are no obstructions, one can put a hose on the actuator and raise one headlight by sucking in the hose with lung pressure. as long as the other side is open to atmosphere. it doesn't require that much pressure differential. when checking these hoses manually (mouthually?) blow them out first. sucking in hunks of bug nests is unpleasant. don't ask me how i know...
Last edited by derekderek; Aug 30, 2021 at 07:13 AM.
I pullled the middle hose the small white striped one that connects to a 3 prong plastic piece and my headlights pop up right away, i have vaccum from that hose also, but when I re put the hose on it puts both headlights down right away . So if I pull the hose and plug it the headlights stay up and I can drive at night this can’t be right anyone have any idea why they won’t come up but when I pull that hose they come up right away
the headlight switch effectively pulls the hose off. the vacuum goes into the passenger compartment and there are 2 switches to shut the vacuum off. one is on the headlight switch, and one is in series with it and mounted on the lowest point of dash pointing down right by the steering column. so, your actuators work and your relays work. you just need to chase down the white-striped command vacuum hose. it is possible somebody hooked the hose going north to the relays straight to the t fitting
Last edited by derekderek; Sep 3, 2021 at 02:12 PM.
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
if its the black and white hose that goes to the metal part of the relay actuator and it has vacuum while its unplugged turn on your wiper switch. the vacuum should go away. If it does not theres a few possiblilites. Either your headlight switch is bad and wont vent the vacuum. the hoses arent connected to the headlight switch. the hoses at the relay itself are hooked up incorrectly.
The 3 plastic nipples are the switched vacuum. the center always has vacuum with the car running. The metal nipple on top has vacuum with the lights off which makes the internal plunger pull vacuum on the top plastic nipple. when the metal nipple had no vacuum when the lights are on a spring pushes the plunger down changing the vacuum to the lower plastic nipple
the headlight switch effectively pulls the hose off. the vacuum goes into the passenger compartment and there are 2 switches to shut the vacuum off. one is on the headlight switch, and one is in series with it and mounted on the lowest point of dash pointing down right by the steering column. so, your actuators work and your relays work. you just need to chase down the white-striped command vacuum hose. it is possible somebody hooked the hose going north to the relays straight to the t fitting
-I don’t have a pull down switch for some reason it just goes from the headlamp switch to the middle prong piece at the front is that a problem.
in your case it is a problem since the vacuum doesn't work on your headlight switch. can you see if you have vacuum at headlight switch when engine is running?
in your case it is a problem since the vacuum doesn't work on your headlight switch. can you see if you have vacuum at headlight switch when engine is running?
- how would I do that just pull both hoses on the headlight switch when the car is on and put my finger over them to check for vaccum?
2020 Corvette of the Year Finalist (performance mods)
2019 C3 of Year Winner (performance mods)
2016 C3 of Year Finalist
Originally Posted by 1973bluevettee
-I don’t have a pull down switch for some reason it just goes from the headlamp switch to the middle prong piece at the front is that a problem.
yes...I keep stating that its hooked up incorrectly...that hose needs to go to the top....deadlight switch is supposed to be small diameter black hose/white stripe...goes to metal port at the top... the hose in the center of the 3 comes from the vacuum tank or if its not connected then straight from manifold vacuum
Headlights
