C3 Headlight Wiring Question

[BBShark]

I think all C3's have all four headlights on (any time the headlights are on). When the high beams are on the second filament in the inside lights is switched on. I have replaced my lights with H9 lights that are single filament lights. I like the "look" of all four lights on but don't want to drive around with bright lights at all times.

So I am thinking that I could wire the outside 2 lights normally and the two inside lights in series to cut their power in half. Then the high beam would switch the two inside lights to parallel (and full brightness).

As I have said before, wiring is not my best subject. So what do you think?

EDIT: C3 don't have all 4 lights on as I thought.

 

[SRountree]

I believe my outside lights are on during low beam and they all come on when I turn on the brights.

 

[phantomjock]

Don't want one to go out and kill them all. Think Christmas Tree bulbs (old style). But is sounds like you've figured that out. Clever - for someone that claims little "sparky knowledge". I'd like to see the diagram when done.

LEDs are getting brighter and running a bit cooler and really reduce power requirements. Just sayin"

Cheers - Jim

 

[BBShark]

I found a method of switching between series and parallel with a DPDT relay. Took me a while to find a DPDT relay that was rated at more than 10 amps but finally found an automotive 30A rated (probably need at least 10A in parallel) . So I could trigger the relay with the dimmer switch.

Relay is also useful for switching directions on a motor like window UP/DOWN

American Zettler AZ2800-2C-12D

 

[vette427sbc]

if You are using halogen bulbs, they will change color while in series vs your low beams at ~14v. Might look funny. New-ish Honda’s do this with their high beam for a daytime running light(although via PWM) and I always thought it looked... not optimal. I do agree that it would look better with 4 lights on vs 2.

 

[BBShark]

Good point. Before I pull the trigger on this, I will power up the lights both ways and see how it looks.

 

[BBShark]

I just powered these up side by side. High beam on 6v and low beam on 12v.

You were right, they don't look optimal, they look awful. They are dim and yellow. So, that's not going to work.

Now I'm thinking of running two low beam headlights (instead of low and high). However the H9 bulbs are 65 watts each. 260 watts of light seems a lot. Each bulb is rated at 2100 lumens.

Maybe if I put a resistor in series with each light to reduce the output ~20% and bypass when brighter lights are needed?

Picture is not an accurate comparison

 

[vette427sbc]

As long as you have them in the proper reflectors, I see no problem with 4 lows.
Another idea might be to put a city light in the high beam reflector... An LED could likely match the color output of your low beams while not drawing much or putting any real light out

 

[mrvette]

BTW putting two loads/lights/resistors is series across a given voltage means each load item gets only 1/4 of the original power.....

the current to each device is cut by 50%, and so is the voltage......

 

[SRountree]

Would this work? They have both low and high beams.

https://www.amazon.com/Motorcycle-H...38&hvtargid=aud-801657747996:pla-837926866526

 

[BBShark]

Those would work but I am pretty much committed to the projectors.

It looks like I can reduce power to all 4 lights with a 1/2 ohm resistor and still get the equivalent of 52 watt headlights. I will technically not have high beams because of the beam spread for high beams is not the same as low beams. But that's OK, I don't see myself driving at night on unlit roads. And I will still have 260 watts of lights.

Got the DPDT relays today and worked up a schematic. I am going to need this for the headlight harness that I am making.

 

[SRountree]

Curious, what's the draw to projection VS LEDs?

I like the LEDs I listed but they are both high and low beams. Is there a watt limit to worry about? It would be easy to hook up all 4 lights to run low beam, all 4 at high beam too. That being said, I dont want to blind people.

 

[BBShark]

I wanted to use projectors because they are smaller and the doors don't have to open so much. I have already modded the doors and linkage to do this so it's too late to turn back.

Don't know much about LED's but I assume they are more efficient than incandescent lights but more complicated. I see some of them have cooling fans.

Here is a CAD model of my setup:

 

[SRountree]

That's really nice looking. What do you think it will cost for the set up? I have seen a couple aftermarket kits but runs over $2500. I have to say though, you're design is awesome!

 

[BBShark]

The headlights are not real expensive. They are Hella 90mm modules, I think I paid $60-70 each. There is a link that needs to be made/replaced that lowers the headlight door and you need to modify the door for the deeper headlight modules.

I still have to make the bezels but I will wait till I get them installed.

 

[vette427sbc]

I did not realize you were running projectors... if it were my car, I would just forget the highbeam function and just run all 4 at full power. Simple and will give you great output without blinding other drivers.
Or
Look up “demon eyes”. people light up the projector lens with a small led. You could turn that on if you still want to run 2 lights for low and get the look of having all 4 lights on.

 

[BBShark]

Looks like 4 fixed lights with a dimmer is pretty easy so I'll give that a shot. Also pretty easy to integrate that into the headlight door motors.

 

[BBShark]

Headlight Warning Switch

I've been making a new headlight wiring harness. After looking at the schematic for a 69 Corvette and see there is wiring for a "headlight warning switch". I am assuming that, on a stock Corvette, you can switch the headlights on without the doors being opened? Thats the only reason I can see to do this and the vacuum/electric switch logic for the headlights is so complicated I can't begin to understand it.

My car will have electric doors. So, I'm thinking, why not have a limit switch on the headlight door so when you switch the lights on, the doors pop up and trip the switch that turns the lights on? Then it would be obvious that your lights are on, no warning switch needed.

Also another unrelated question but part of the wiring I don't really understand. Maybe someone here can answer. The 69 schematic shows Left & Right Hand Courtesy Switch and Key Warning Switch connectors. The switches for the Courtesy Lights is straight forward but the Key Warning wire goes to the Horn & Turn Signal Switch connector. My guess is that this sends 12V to the horn relay and causes it to "buzz"? Is that correct?

 

[vette427sbc]

I've been making a new headlight wiring harness. After looking at the schematic for a 69 Corvette and see there is wiring for a "headlight warning switch". I am assuming that, on a stock Corvette, you can switch the headlights on without the doors being opened? Thats the only reason I can see to do this and the vacuum/electric switch logic for the headlights is so complicated I can't begin to understand it.

My car will have electric doors. So, I'm thinking, why not have a limit switch on the headlight door so when you switch the lights on, the doors pop up and trip the switch that turns the lights on? Then it would be obvious that your lights are on, no warning switch needed.

Also another unrelated question but part of the wiring I don't really understand. Maybe someone here can answer. The 69 schematic shows Left & Right Hand Courtesy Switch and Key Warning Switch connectors. The switches for the Courtesy Lights is straight forward but the Key Warning wire goes to the Horn & Turn Signal Switch connector. My guess is that this sends 12V to the horn relay and causes it to "buzz"? Is that correct?

Can you post the diagram for the headlight warning? I forget what the warning was for, Presumably what you said though...

Are you trying to keep the warning light functional?

Most of the electric headlight door kits are wired into the headlight wiring, so when you turn the lights on, it tells the doors to open, and when you turn them off they close. Kind of eliminates any question if all systems are "go" or not... Unless there is a failure, but like you said, its pretty obvious if the lights arent on or a door isnt open.

 

[BBShark]

It looks like the switch is on the headlight door somewhere. I don't have access to an original car so I'm just speculating. The switch goes to the warning light and then the power terminal on the headlight switch.

If opening a headlight door switches the headlights on, I think that is all I need. So, no warning light is my preference.

 

[MYBAD79]

I just did my electric headlight pop up conversion, no more vacuum. I made my own haness with three relays, main power from the battery thru two 12 ga wires to the front where the relays are, low beam switch turns on the motor relay and the low beams, high beam switch turns on the high beams, low beams stay on, works like a charm... original wiring turns low beams off when high beams come on.. guessing that running four lights thru the stock switch would kill tje switch quickly, now the switch only powers the relays instead of all lights... no warning switch... why ? simplicity.. first off, you cannot miss the headlights popped up and shining when you get out of the car.... secondly, I always disconnect my battery via switch when I park the car anywhere, makes it more difficult to steal it too ??

 

[BBShark]

Looks like all C3's have switches on each headlight door. Below is a picture of the switch and most of the vendors sell the brackets. What a goofy setup. Suppose it is because the doors are vacuum so you could have the headlights on with the doors down.

 

[BBShark]

My next headlight mystery is RPO CD-4. Yeah I know wtf does that mean? Turns out there is wiring on the engine harness that routes through the windshield wiper pump that operates headlamp washer nozzles! I had no idea a 69 Corvette had this. This is really made difficult because the Lectric Limited harnesses have all options built in, even obscure ones and the schematics I have don't really show options.

Now I'm trying to get a 1974 wiper motor to work with the 69 harness.

 

[BBShark]

Finnaly got this sorted out. I am going to run the 4 low beam headlights on 80% power and high on 100% by running the low power wire through a resistor. The headlights are switched on when the headlight doors open up (by adding a switch to each door). I also added a switch to the box that allows the headlights to open without turning the lights on. The box will be located behind the grill so that the resistor will be exposed to airflow and insulated from engine bay heat. Box also contains the two relays and protects them from water.

Module


Switch