jogasz28
Apr 28th, 05, 06:30 PM
After reading the recent headlight post "68 RS headlight assemblies", I decided to get my own working. I looked at the link:
http://www.camaros.net/techref/articles/rpoz22_1.htm
It was very good at explaining how the system works. Basically vacuum is supplied at the center port of the switching valve, and according to the headlight switch signal to the switch diaphragm, moves the valve stem to port vacuum to the upper or lower port to open or close the headlights
| |====== upper port
| |====== center port
| |====== lower port
I verified that I had 12" vacuum at the center port, but had no vacuum at either upper or lower port. I should have vacuum at one or the other.
I removed the switching valve. I then removed it's end filter exposing the valve stem end. I used a dowel to push the stem in and then let it spring back out. This mimmicks the diaphragm action on the other end. When I moved the stem, still no proper vacuum at the ports. After finding out a new switching valve is $70, I decided to try and get this one to work.
First I cleaned the valve innards with some simple green and flushed. This did get a little opening between the middle and lower ports( I blew into the middle port to check). I then used a pick to probe into the upper and lower ports. I felt something blocking both ports. When I cleared this out of the way, I could then easily blow between middle and upper or middle and lower depending on where I positioned the valve stem. I don't know what it was because nothing came out of the valve. Possibly plastic flashing.
Anyways, I reinstalled the switching valve and my headlight doors work! They're a little sticky from non-use, but I've lubed them generously and they're getting smoother each time I use them.
It goes without saying this fix applies only if the switching valve is the problem. But knowing this allows anyone to temporarily port engine vacuum to each headlight canister's open or close hose to check it's operation.
The ends of all my hoses wer cracked so I used the method of heating the hose ends with a heat gun and then pushing them on. This worked great, no cracks!
http://www.camaros.net/techref/articles/rpoz22_1.htm
It was very good at explaining how the system works. Basically vacuum is supplied at the center port of the switching valve, and according to the headlight switch signal to the switch diaphragm, moves the valve stem to port vacuum to the upper or lower port to open or close the headlights
| |====== upper port
| |====== center port
| |====== lower port
I verified that I had 12" vacuum at the center port, but had no vacuum at either upper or lower port. I should have vacuum at one or the other.
I removed the switching valve. I then removed it's end filter exposing the valve stem end. I used a dowel to push the stem in and then let it spring back out. This mimmicks the diaphragm action on the other end. When I moved the stem, still no proper vacuum at the ports. After finding out a new switching valve is $70, I decided to try and get this one to work.
First I cleaned the valve innards with some simple green and flushed. This did get a little opening between the middle and lower ports( I blew into the middle port to check). I then used a pick to probe into the upper and lower ports. I felt something blocking both ports. When I cleared this out of the way, I could then easily blow between middle and upper or middle and lower depending on where I positioned the valve stem. I don't know what it was because nothing came out of the valve. Possibly plastic flashing.
Anyways, I reinstalled the switching valve and my headlight doors work! They're a little sticky from non-use, but I've lubed them generously and they're getting smoother each time I use them.
It goes without saying this fix applies only if the switching valve is the problem. But knowing this allows anyone to temporarily port engine vacuum to each headlight canister's open or close hose to check it's operation.
The ends of all my hoses wer cracked so I used the method of heating the hose ends with a heat gun and then pushing them on. This worked great, no cracks!