Headlight relay on '68 911

[Fritter]

What is the purpose of the headlight relay in a SWB car (#43 in the wiring diagram)?

It looks like the purpose is to route the high beam circuit power through the light switch and relay and not the hi/lo stalk, and then to split the low beam circuit between light switch and relay, while still running through the hi/lo stalk?

I'm going to install H4's with the fluted VW non shelf lenses in my 68 this winter, and I want to run the "big boy bulbs", 80/100W.

I'm thinking I need to install the relay kit still, because even with the rube goldberg relay that Porsche engineered, the power still runs through the light switch and the hi/lo stalk to some extent. Especially with 80/100 bulbs!!

Thanks for any responses.

[raspy2point2]

Hi Fritter-- I am doing the same thing. H-4 with the flutted lenses from VW that I bought at Wolfsburg West in So. Calif. My 68 911L is a ROW car and calls for the flutted lens anyway unlike the clear front lens on the US spec cars. This car is new to me so I have no knowledge about the hook up--sorry. Chris

[savaden]

The headlight relay is a logic relay that works in conjunction with the flasher switch in the stalk. Depending on the position of the headlight switch, Off, parks only, on, the relay ensures that there will be a flash signal when the stalk switch is pulled, regardless whether the high or low beams are on at the time.

If you want to install headlight relays to protect the switch from high current, I would suggest mounting the relays up front by the headlights, or even inside the headlight buckets.



the details of this kind of installation have been discussed over at 356Talk.

http://porsche356registry.org/356tal...Cspan+class%3D

The 12V relay is Mouser part number 528-9152-12

You can get the Flag terminals at Radio Shack.

SV

[Fritter]

Thanks for the feedback, I was thinking the relay is only for the flasher.

For 12V the voltage drop over the few feet of wire may not be as great, so I may mount the relays by the fusebox in my '68. 6V is an entirely different animal!!!

Even with 12V sealed beam halogens, my '68's stock sugar scoop headlights are like "glowing orbs". I can't wait to get better lighting on the car, it will make nightime driving much less stressful and "conestoga wagon" like.

Plus, the H4's with the Beetle fluted glass just looks way better than sugar scoops.