wiring in auxilary lamps

[JasonGrahn]

Okay, wiring is not one of shining areas, so i'm hoping for some clarification on this.. I've learned that we have a "ground-switched" lighting system in the car. we'll assume one set of driving beams at this time, once i have one set figured out, the others will be easy.

I would like to use a 3 position switch for the lamps. On-Off-On. The top "On" switch would run the driving beams only when the brights are activated. Off is obvious. When the bottom "on" is activated, the lights will run independant of the headlamp status.

Taking what i learned from here: http://www.rallylights.com/useful_info/ ... wiring.htm I know that i have to apply the fused, constant 12V power supply to relay pin 85 as well as pin 30. Is this correct? Then, the high beam circuit and switch will be applied to pin 86, correct? This doesn't seem right.

If this is correct, then powering the lights is easy and i've got that down, now the switch will be the next step. I've got 3 prongs. I understand this as +, -, +. It seems that if the previous paragraph is true, then the wire coming from pin 86 is hot and therefore i would be connecting a + to the center pin. Does it matter if the center pin is connected to a ground? If not, then i am correct in saying that the other two pins of the switches will need to be connected to two ground points. The upper "on" will be routed back to the headlamp ground, completing the switched-ground circuit for the lamps to be on only while the brights are in use. The lower "on" will be grounding any-ol' where i please, creating the circuit where the lights will be on free of headlamp status.

If this is incorrect, please indicate where i have errored. A diagram or picture would be helpful if possible.

This is the diagram i am looking at from the above website:

[vrg3]

I would like to use a 3 position switch for the lamps. On-Off-On. The top "On" switch would run the driving beams only when the brights are activated. Off is obvious. When the bottom "on" is activated, the lights will run independant of the headlamp status.

Just wondering... when would you want to run driving lights without high beams? Or is this just to keep the discussion generic?

I know that i have to apply the fused, constant 12V power supply to relay pin 85 as well as pin 30. Is this correct? Then, the high beam circuit and switch will be applied to pin 86, correct? This doesn't seem right.

Yes, that would work okay. Make sure the relay you're using doesn't have a diode built-in, or if it does, make sure you're wiring pins 85 and 86 in the right direction.

If you can find them, I recommend relays that have dual 87 terminals. That way you can run one wire to each lamp.

If you're using an SPDT relay (has an 87a terminal in the middle), I'd suggest running the +12v to terminal 87 and connecting the lamp to terminal 30 instead of the reverse. That way when the circuit's off you don't have a hot terminal in the middle of the relay.

If this is correct, then powering the lights is easy and i've got that down, now the switch will be the next step. I've got 3 prongs.

How does a 3-position switch only have 3 pins?

Most have 4. Call them A, B, C, and D. Pin A is connected to either B, C, or D depending on the position of the switch.

Or does the switch you're using leave out pin C?

[JasonGrahn]

Just wondering... when would you want to run driving lights without high beams? Or is this just to keep the discussion generic?

to keep the discussion generic.

Yes, that would work okay. Make sure the relay you're using doesn't have a diode built-in, or if it does, make sure you're wiring pins 85 and 86 in the right direction.

If you can find them, I recommend relays that have dual 87 terminals. That way you can run one wire to each lamp.

If you're using an SPDT relay (has an 87a terminal in the middle), I'd suggest running the +12v to terminal 87 and connecting the lamp to terminal 30 instead of the reverse. That way when the circuit's off you don't have a hot terminal in the middle of the relay.

Yes, the relays have the 87a terminal in the middle. its been suggested to me to put an insulated cap on there and that will take care of the issue. But i understand your point and that makes sense.

How does a 3-position switch only have 3 pins?

Most have 4. Call them A, B, C, and D. Pin A is connected to either B, C, or D depending on the position of the switch.

Or does the switch you're using leave out pin C?

My switch doesn't have a light to it. A lit 3 position switch would have been the ideal, but the only ones i could find locally were a bit more then i was willing to allocate on this project.

[vrg3]

My switch doesn't have a light to it. A lit 3 position switch would have been the ideal, but the only ones i could find locally were a bit more then i was willing to allocate on this project.

Even an unlit 3-position switch -- how does it only have 3 terminals?

I guess I'll assume it's lacking a center terminal. So it has one common terminal, and two outputs. When the switch is in the center position neither output is connected to the common terminal.

If that's the case, then you connect the common to terminal 86 of the relay. Then, one of the outputs goes to ground and the other to the high beam circuit.

[JasonGrahn]

Cool. I've got my map all made up. Thanks for the input. Now to find where the highbeam and lowbeam sides of the 3 position switch should be wired into the circuit. Any tips?

[vrg3]

Look under the dash on the driver side. Look for the connector coming from the lighting switch.

It's a big 8-terminal connector. The terminals are approximately the same size as the spade terminals on relays. I wanna say it's a blue connector but it might be black; can't remember. The wires on the car side should be green, red, yellow-with-blue-stripe, and black. The red one is the high beams and the yellow-with-blue-stripe one is the low beams.

I think that's right... if it's a Canadian car the colors may be different; I'm not sure. Check that you have the right wire by checking if it's grounded when the high beams are on.

[JasonGrahn]

For those also tackling this project, on my 1990 US model, i found the following to be true:

The connector vrg3 is referring to is a black 8 pin connector to the right of the steering column.

The colored wires on the car side to look for are Yellow/Blue and Red. The Yellow/Blue wire controlls the high beams. The Red wire controls the low beams.

On the steering wheel side of the connector, the connected wires are Red/Yellow for the low beams and Red/Black for the high beams.

[vrg3]

I stand corrected.

So did it work?

[JasonGrahn]

On the steering wheel side of the connector, the connected wires are Red/Yellow for the low beams and Red/Black for the high beams.

Whups, this is backwards.

red/yel = high beams
red/blk = low beams

Wiring it up worked with a few exceptions. 1: my power mirrors aren't working. No idea why. 2: the fog lamps that i wired do not shut off when the vehicle is shut off. I believe this could be remedied by NOT wiring pin 85 to the battery, but instead wiring it to the power wire going to the headlamp or something "turn-off-when-the-car-is-turned-off" related.

Other then that, Lookin good. Wish i had the 80 Pro Xt's that i was looking for though, i'll only have fogs for the time being.

[vrg3]

Wiring it up worked with a few exceptions. 1: my power mirrors aren't working. No idea why.

Do you think this is related?

2: the fog lamps that i wired do not shut off when the vehicle is shut off. I believe this could be remedied by NOT wiring pin 85 to the battery, but instead wiring it to the power wire going to the headlamp or something "turn-off-when-the-car-is-turned-off" related.

Yes, that would fix the problem. But you don't really want to do that since then your lights will have to suffer the voltage drop from stock wiring.

What's happening is that when you shut off the ignition, the relay coil finds a ground path through the headlamp filament and other accessories in the car.

I think the best way to go might just be to stick in another relay to only close the circuit when the car is running.