C3 Headlight Switch Hoses

[Tommy F.]

Silly question,

There are 2 hoses on the headlight switch....does it matter which hose is on which nipple?

I just replaced an operating switch ( the rheostat was shot ) with a new switch from CC...I did not test the new switch with the motor running before I buttoned everything up...now, I can hear a vac leak, and must use the emergency switch to open the lights. I can see that the hoses are securely on the nipples..

[Roger O.]

Re: C3 Headlight Switch Hoses

Yes it does make a difference. If you have colored strip hoses the blue hose goes to the port towards the front of the car. White to the other port.
If you don't have colored hoses the port closest to the knob is the source vacuum port-in other words with the car started find the hose with vacuum on it and that is the source vacuum hose.

[Tommy F.]

Re: C3 Headlight Switch Hoses

Thanks Roger...

I was able to use long needle nosed pliers to swap the hoses...that did the trick.

The only puzzling part is that the hose nearest the knob was a blue striped hose...possible that the vendor has supplied a switch with ports reversed.

Fully operational now.

Thanks again,

[Greg A.]

Re: C3 Headlight Switch Hoses

Tommy, it's been several years since i changed the original switch on my '78 for a new repop (rheostat wasn't working either), but i found the quality of the repop to be poor. After about 6 months, the switch started to leak and I ended up cleaning the rheostat on the original switch and putting it back in.

This was 5 or 6 years ago, about the time the original GM switches seemed to disappear. I hope the quality is better on the switch you installed (I think one of the plastic seams split), but hang on to the original.

Greg.

[Roger O.]

Re: C3 Headlight Switch Hoses

Tommy, it's been several years since i changed the original switch on my '78 for a new repop (rheostat wasn't working either), but i found the quality of the repop to be poor. After about 6 months, the switch started to leak and I ended up cleaning the rheostat on the original switch and putting it back in.

This was 5 or 6 years ago, about the time the original GM switches seemed to disappear. I hope the quality is better on the switch you installed (I think one of the plastic seams split), but hang on to the original.

Greg.

I agree the new switches need a little attention.
The first thing I do before installing a new switch is solder terminals #3 and #4 for a better connection. Second thing I do is shoot heavy silicone inside the vacuum valve and work the switch in and out.
Vacuum port #3 is for the blue hose and this blue hose goes to the pulldown bypass switch.
Vacuum port #2 is for the vacuum supply via T via check valve.