72 headlights pop up at statr up.

[Richard R.]

I replaced all vacum lines , the actuators (wiper and headlight) and still get the headlights poping up when the car is started. What should I look for next?

[Edward J.]

Re: 72 headlights pop up at statr up.

Rich, do the headlamp doors pop up and stay up or do they cylce up then down?

[Jack H.]

Re: 72 headlights pop up at statr up.

What is the condition of your vac filter & check valve? These are often overlooked during vac system troubleshooting...

[Edward M.]

Re: 72 headlights pop up at statr up.

Check the canister seals (all three).

[Richard R.]

Re: 72 headlights pop up at statr up.

The headlights pop up on start and then go down a few seconds later. The fiter and check valve are working fine.

[Edward J.]

Re: 72 headlights pop up at statr up.

Rich, I don't know if you have checked the vaccum switch on the pass side wiper arm, but when they break they cause unusual problems, because vaccum signal on the switch also feeds the headlamp doors if the internal plunger breaks and is stuck between the feed ports this will cause the cylcing on start, they are plastic shaft with a o-ring style seal on the plunger.

[Roger O.]

Re: 72 headlights pop up at statr up.

You most likely have a leak in the small hose circuit. Take the white and red at the switch under the right wiper arm and nipple them together and see if that takes care of the up and down cycle on start up. If it does the switch could be out of adjustment or leaking.
(Turn your black knob bypass to off or pull the 3 wire connector at the motor in case you want to use the wiper switch to open and close the door so you don't pinch the wipers.)

[Richard R.]

Re: 72 headlights pop up at statr up.

Thanks Roger, I tried putting the white and red hose togther but the headlights still pop up. Any more ideas?

[Roger O.]

Re: 72 headlights pop up at statr up.

I usually have a bunch of ideas when it comes to vacuum.
With the engine running pinch the small hose coming off the metal check valve and wait about 15 seconds,if somethings pops up you have a leak in the small hose circuit.

[Richard R.]

Re: 72 headlights pop up at statr up.

Ipinched off the small line and the wiper door popped up. I replaced the wiper safety switch but they all leak (won't hold vacum) with the plunger open or closed using the test process of prior thread. Does any body make a good vacuum switch?

[Edward J.]

Re: 72 headlights pop up at statr up.

Rich is the wiper arm restings against the button on the safety switch? To shut down the vaccum signal. I have seen the arm needing adjustment.

[Richard R.]

Re: 72 headlights pop up at statr up.

Yes the arm is pushing the switch down. I have even tried playing with the the depth of the arm to see if I could get it to hold vacuum but it just leaks down. the switches don't work, I had 2 new ones sent and even called the vendor and told him what was going on. He was very helpful and tested his inventory and could not get any to hold vacuum.

[Patrick H.]

Re: 72 headlights pop up at statr up.

Yes the arm is pushing the switch down. I have even tried playing with the the depth of the arm to see if I could get it to hold vacuum but it just leaks down. the switches don't work, I had 2 new ones sent and even called the vendor and told him what was going on. He was very helpful and tested his inventory and could not get any to hold vacuum.

You're correct - most (maybe the vast majority?) of the repros leak. I went through a couple to find one that worked. I can't recall if I then used it, or used parts of it to rebuild the original that was on Dad's car. It's been 10 years after all...

One trick I've used is to totally disconnect the "control circuit" from the system and see what happens. In the picture below, you can see where the vacuum line from the engine heads up and left (relative to the photo) and splits at the check valve. The best way is to disconnect the line that goes up and over the brake booster, and connect it directly into the engine at the intake. If you then start the car and the headlight doors stay down, you've verified the integrity of everything from that point to the front of the car, and your leak is somewhere in the control system.

Oh, and as Jack mentioned, double check the integrity of your check valve. Some repros don't work well.

If you still can't figure it out Doc Rebuild has a great troubleshooting guide that is well worth the $.

[Edward J.]

Re: 72 headlights pop up at statr up.

I must of got lucky with my 72 I picked one up in Carlisle last year at Smart Parts tent. for 25 bucks. the top button was snapped off on mine.

[Roger O.]

Re: 72 headlights pop up at statr up.

Many of these aftermarket switches are no good. There is another switch on the 77-82 cars that controls the vacuum to the heater shut off valve that you can substitute if you can find a good one of those. You will have to transfer the bellows that covers the spring.