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Randall C
Randall C, ASE Master Tech
Category: Mazda
Satisfied Customers: 12824
Experience:  ASE Master Certified, 35 yrs, Diag/Electrical Specialist
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Have a 2006 Mazda 6. I'm trying to add a light to my

Customer Question

Have a 2006 Mazda 6. I'm trying to add a light to my vehicle. I want it to only come on when I have my high beams on. I'm having a hard time figuring out how both the low and high beams use the same relay and have 12V at the same time but only one or the other comes on. How can I find the actual 12V wire that powers the bulb/relay/fuse so I can wire in another relay for my new lights?
Found a wiring diagram but it just isn't making sense to me
Submitted: 1 year ago.
Category: Mazda
Expert:  Randall C replied 1 year ago.

Hello, I have to pull diagrams and review them, meantime, I need to know if you have DRL

Customer: replied 1 year ago.
Hi,Forgot to add that I do not have DRL
Expert:  Randall C replied 1 year ago.

bear with me

Customer: replied 1 year ago.
Sure, Thanks. The schematic won't lie but its just weird that there is a separate bulb for high and low beams but the high beam gets the 12V and Ground when the low beams are on but doesn't come on until the switch turns it on
Expert:  Randall C replied 1 year ago.

the thing you are missing is the switch ONLy makes a ground, thus why power to each low and high from the relay. You will have power to all bulbs pretty much all times, till the switch makes a ground. To add a light that lights with highs only? you have to use a relay, A 4 pin aftermarket relay in which you have to look at side of relay for pin diagram but what you will do is this, in general. You need 12 volts all the time to one pin, then 12 volts to the leg pin , then a wire to the light you want form 3rd pin, then? the ground pin goes to the Light green/red wire to a headlight,. so, hard to expalin, but a relay has a coil. so, 12 volts to one side of the coil, the ground to the light green/ red from a headlight, 12 volts to the other side of the coil in relay and 12 volts to the leg contact in the relay. I have included a link to look at, so,, with a 4 pin relay, so, 12 volts to [pin86. 12 volts to pin 30, wire from 85 to one of your headlights light green/ red wire, and the last one pin 87 goes to your new ad***** *****ght

Customer: replied 1 year ago.
Ok, I've got a good understanding about relays, thanks for sending the diagram.Here's what I found when connecting to the light green/red wireThere is no voltage on the wire when the lights are off. When the low beam lights are turned on it provides 12V to that wire. When the high beams go on, it almost goes to 0VIf I wire my relay to that light green/red wire, I will need to trigger off 0V (Ground) correct?
Expert:  Randall C replied 1 year ago.

i have no idea how you are getting 12 volts on the high beam wire,. The switch only makes a ground to turn the high beams on, You need that trigger to the relay NEG coil side to entergize the coil, it closes, sends power to the light you are adding, The low and high beam are different circuits, Nothing in any diagram and what I know why you have 12 volts when lows are on, I would follow what I wrote and use the lt green /red form either light to your aftermarket relay, I am sure and confident it will work look close at this diagram which you say you have

Customer: replied 1 year ago.
That's why this is so confusing to me. I understand 12V wiring so it didn't make any sense. I'll give it a try
Expert:  Randall C replied 1 year ago.

I sent what I can, You must use a relay and wire as I have instructed. It will work

Customer: replied 1 year ago.
Ok, well it comes on, however there's a small issue. When the light is off, the ground is on. When the low beams turn on, the ground shuts off. When high beams come on, ground comes back on.Is there another relay somewhere upstream that is switching the ground on and off? There must be something
Expert:  Randall C replied 1 year ago.

without DRL? no, when you have a ground to either high beam? they will be on, so not making any sense to me at all, Low and high are not tied together. , You have the diagrams, there is not another relay, the switch simply makes a ground on the Lg/red wire to both high beams

Customer: replied 1 year ago.
Yea, no DRL. Just orange parking lights.Think I'm going to have to dual relay this to make it work
Expert:  Randall C replied 1 year ago.

I am going to opt out, dual relay is not what is needed, Its a simple circuit, so another expert is going to have to chime in, Please save the rating/ feedback for the next expert

Customer: replied 1 year ago.
The reason I say a dual relay is because I'm getting 0V from green/red wire when lights are off and then 12V when the low beams come on. Meaning when the car is off it completes the circuit and my new light would come on.If I take the 12V from the headlight it is off when the car is off and stays on the entire time.So If I get my 12V from the headlight thats the same as using the ACC for a radio and that wouldn't come on until headlights are on. The Ground goes off until the high beams are on. So I would get me 12V and 0V then but would need two relays