Linking headlights to interior light

[geraintthomas]

Originally Posted by Meir

the short answer to your question is yes.




First I need to correct PW. As I mentioned in one of my previous posts, the courtesy light trigger is positive.
With that said, it doesn’t really matter.
Once you use a relay (and you must in this case) the polarity of the trigger is irrelevant.
You just need to connect the other side of the solenoid to the opposite polarity.
The solenoids is like a bulb, it will work once it gets positive and ground in the two poles, and it doesn’t matter which pole gets which polarity. (I hope I’m not confusing too much)
If you guys a really interested to understand how a relay works, let me know and I’ll make a short video.
Back to the car.
In our case, we will need to use two relays due to the fact that the lights system is divided to left and right. You have two wires coming out of the switch, and two fuses on the fuse box. So each line needs a relay.
I was working a bit on my car this weekend, completing the installation of an “in dash” in garage opener, and started working on the electrical system of my home made PSE.
So I looked around a little bit, and it looks like the easy way to accomplish this mode, will be doing it behind the light switch. It is really simple project.
I promise to show in detailed how it’s done. I just need to find the time to do it.

You're a star.

With the courtesy lights and the parking lights both being 12v, I thought it didn't even need a relay.

I've got footwell lights that come on when the courtesy lights come on, and dimmer ones that come on when the parking lights are on (for ambient night driving). I would have thought that, if both parking and courtesy lights are triggered by positive, then you'd simply splice the two with a diode, so one can turn the other on, but not the other way around.

But, I know very little about electronics and there's probably a very simple explanation to why that doesn't work when you get it working, do tell!

I've also got bypass pipes, and would have loved electronic valves. The electrics aren't worrying me, it's what valves to use. They'd need to be small to fit in the space. What did you use?