stevecstl

The headlamp doors open very slowly; one opens slightly faster than the other. The speed at which they close is ok, however they close in sequence, not in parallel. I have rebuilt the actuators and the vacuum lines seem to be in good shape...so could it be something as simple as the check valve or do I need to think about replacing one or both of the headlamp actuator relay(s)?

Peterbuilt

I shot some penetrating oil into the relays, it speeds them up for a while, but new relays are a better fix. Also you can cut back the vacuum hoses about a half an inch to make a better connection. PG.

kydirt

Your relays probably leak. They have a rubber "piston" in them and when the rubber gets hard they leak. Instead of buying new ones, I uncrimped the rod on mine, pulled the piston out and fabbed a new piston out of a 3/8" aluminum rod then fitted the new piston with o-rings. I can't believe how fast they work now. I did not take the diaphram apart on them because it didn't leak.

justanotherdoe

How much vacuum do you have? More vacuum = faster light operation.

Mine have always opened/closed in sequence, even when I had both activated through the same relay.