80L48

I just recently purchased a 1980 COrvette and the lights are coming up inconsistently. I have found some great diagrams/troubleshooting guides in the forum.

However, my questions is: On a 1980 Vette is their supposed to be a Wiper door? I seem to have some sort of a solenoid coming off of the vacuum line between the check valve and the headlight switch. I don't appear to ave any kind of wiper door and not sure I am supposed to (I do not think so)... I see some posting that say 68-72 and others that say all the way to 82, but they may be generalizing the entire vacuum system.

If I am not supposed to have a wiper door, what is this solenoid for?

gbvette62

The vacuum controlled wiper doors were on 68-72's only.

Coming from the intake vacuum fitting, there is first a white plastic filter, followed by the metal check valve, which has s single inlet port and two outlet ports. Is the filter what you're thinking is a solenoid?

A common cause of one lamp coming up quicker than the other, is a bad actuator seal, in the slower lamp actuator.

Alan 71

Hi 80,
No, the last model year for cars with wiper doors was 1972.
In looking at a vacuum hose diagram for 80 cars I do see a T in the line from the check valve headed forward to the headlights, but not one in the line to the headlight switch.
So I'm not sure what you're seeing?
I believe 'cruise control' needs a vacuum supply….could that be what you're seeing?
Regards,
Alan

Hi gb, I was typing and you were posting!!!

The filter and check valve that gb mentions:

80L48

there is another T after teh filter and check valve. The T connector is in between the headlight switch and the Check valve. The le off of the T, goes to a solenoid mounted on the firewall. On the back of the solenoid is a wire connector whih then goes into a wire harness.

This 1980 has a "Lock-up Automatic Transmission". Apparently there is a sensor for this transmission feature that connects to a vacuum line somewhere..... I am starting to think it is tied into the headlight system vacuum. Does that seem right?

fishslayer143

Alan, do you ever drive that car? DAMN, that thing is spotless!!! KUDOS !!

SwampeastMike

I'm pretty sure the "T" you're talking about provides a branch for the vacuum operated HVAC system. Is one of the hoses on that tee extremely small? If so that's the one feeding the HVAC.

0Willcox Corvette

80 had a transmission converter switch located at the center of the firewall. But I'm not sure where the vacuum feed was supposed to be pulled from. The hvac hose as Swamp stated, did split off a T from the hose leading into the headlamp system.

lionelhutz

The converter vacuum switch would (should) not be fed from the headlight system after the check valve. That part of the system has a constant vacuum and the converter switch needs to see the varying manifold vacuum to sense engine load.

Alan 71

Hi lh,
Isn't there contestant but variable vacuum AFTER the check valve any time the engine is running?
The AIM shows the switch in the large 'supply' hose to headlights, NOT the small 'control' hose on it's way to the headlight switch as 80 described.
Is that correct?
Regards,
Alan

Wife's Vette

Being new to the site/Forum, I have nothing to say that could help you....sorry.

But I was directed to this thread to ask a headlight system question....
that question is,.... how are we supposed to adjust the light 'door' to close without hitting the body? When the light closes it hits the front, and when it opens it hits the back, causing paint to chip and the wife to cringe.
Any help would be greatly appreciated.
thanks.

lionelhutz

The system after the check valve feeds the lines and a tank in the front to store vacuum, so I can't see the vacuum in that section varying with the engine vacuum.

Peterbuilt

Does an 80 need a 2 port or 3 port fitting like this one?

http://www.zip-corvette.com/77-82-in...-fitting.html#

croaker

Restart another Thread don't hijack this one where your bearing are you adjust there. Someone will chime in and lead you

SwampeastMike

3-port if you have cruise AND automatic transmission. 2-port if you have cruise OR automatic transmission. 1-port if you have NEITHER cruise NOR automatic transmission.

Gale Banks 80'

Most problems with the vacuum are dried out Hoses and Seals. Don't expect both Lights to open exactly at the same moment. Since most problems are vacuum You should be able to hear the leak. That's is if the Engine is not running. Run a long hose outside your shop to a vacuum pump or another vehicle. Now You can hear the leaks. In 1980 they changed the Hood a bit and there was a clearance issue with the Vacuum cans that open the lights. The easy fix was for GM to switch the two cans from left to right. The only diffrence is the angle that that the vacuum lines hook up. A lot of vendors don't know this and if you order a replacement there is a pretty good chance You will get the wrong one. A lot of the Diagrams for the Color Codes of the Hoses are also wrong in this area for the 80-82 cars.

7T1vette

Primary cause for slow or inconsistent headlamp opening/closing is worn out vacuum relays (the '80 may have one or two of them). These are the devices that receive and distribute the vacuum signals to the headlamp actuator cans. When the seals wear out, vacuum signal is lost and actuation becomes sluggish.

For the headlamp 'buckets' to be hitting your body panels, there must be a break in one of the pivot mounts. Sometimes, when the bucket pivots don't get lubed, they can bind and generate enough force to fracture an aluminum mount. You'll just have to remove the front headlamp cover to find out what's wrong with the mecanism. You will want to shoot some rust penetrant on any screws holding that cover and let it work for a day or two before trying to remove the screws. Trying to force them to break loose can cause the threads in the headlamp frame to strip, so be a little cautious with them.

80L48

Thanks for al the replies, this 1980 vette is an automatic and does appear to have the "lock up" sensor after the check valve. The small hose did have a leak in it. Also, The check valve is bad as it allows air to flow in any/all directions. After replacing these, I'll continue to diagnose. No leaks now through the manual switch and headlight switch hoses.

However, This vette only has 1 relay up front. It appears that the hoses are each "T"d right before/after the 1 relay, This would seem to work (and eliminate a failure point).

Anyone know of any issues with only having a single relay?

7T1vette

One relay will work fine...if it works. Originally, the C3's had two [separate] headlamp actuator/relay sets...one for each bucket. That way, if one failed, you would still have the other to give light for night driving. The frequency of that problem was rare, so GM chose to save some money and only install one.

If you only have one relay and the headlamp buckets come up differently, you either have a lubrication problem on the raise/lower linkage parts and/or you have leakages in one or both actuators.

80L48

well after determining and resolving 2 hose leaks, a bad check valve and a somewhat clogged filter, lights are working! (although not exactly in sync with each other, but great progress!)

SwampeastMike

Great news!

Exactly in sync is probably impossible for any period of time but you can definitely get them working such that they rise very quickly with clearly audible snaps as they lock into position with less than a second difference.