Aux light options
This post is essentially me going full nerd on wiring options for aux lights. This is the thought process I went through when I was deciding how I would wire ours up. It seemed like a good idea to write it down so it might help someone else decide on what is right for them.
Option 1: Work lights
How it works: The lights come on when you flick the switch.
Good:
1. Easy and quick to wire up.
Bad:
1. The switch can only be in one place, if it's the front then that's annoying if you're at the back and vice versa.
2. If the switch was in the cab you could accidentally (or deliberately) switch them on when driving normally. This would not make you many friends, especially among traffic cops.
3. You can run your battery flat if you leave them on without the engine running.
Option 2: Aux reverse lights
How it works: You flick the switch and your lights come on automatically when you engage reverse, and turn off when you disengage it.
Good bits:
1. No blinding people by accident when driving forwards.
2. Light up switch can tell you that your lights are linked to reverse.
Bad bits:
1. Can't be easily used as work lights.
2. If you have a switch that lights up when it's closed, the LED will slowly drain the battery if you leave the it closed. ( you must choose between potentially draining your battery or not having a pre-warning that the lights are linked to reverse. )
3. Involves cutting into factory wiring.
4. You can't drive forwards with the lights on, they only work in reverse.
Option 3: Aux reverse with piggyback
How it works: You flick the switch and your lights come on automatically when you engage reverse, going off when you disengage it.
**This would work very well as a way to link aux headlights to your main beam, just splice into the main beam power feed rather than the reverse lights. **
Good bits:
1. No blinding people by accident when driving forwards.
2. Light up switch tells you if lights are linked, and will go out when the ignition is off, leaving no drain on your battery.
Bad bits:
1. Can't be easily used as work lights.
2. Involves cutting into factory wiring.
3. More complicated to wire up.
4. You can't drive forwards with the lights on. They only work in reverse.
Option 4: Aux reverse piggyback + work lights
How it works: You flick the switch in the cab and your lights come on automatically when you engage reverse, going off when you disengage it. You also have a second switch elsewhere which turns on the lights, drawing power from an aux battery.
Good bits:
1. No blinding people by accident when driving forwards.
2. Light up switch tells you if lights are linked, and will go out when the ignition is off, leaving no drain on your battery.
3. Can easily be used as work lights, potentially running off a separate battery, so your starter is safe.
4. You can have them on when driving forwards. But you must get out the cab to do this. You therefore can't do it by accident.
Bad bits:
1. Quite complicated to wire up.
2. Involves cutting into factory wiring.
Option 5: Aux reverse piggyback + work lights with two lights.
How it works: You flick the switch in the cab and your lights come on automatically when you engage reverse, going off when you disengage it. You also have two switches elsewhere which turn on the two lights individually, drawing power from an aux battery.
Good bits:
1. No blinding people by accident when driving forwards.
2. Light up switch tells you when lights are linked and will go out when the ignition is off, leaving no drain on your battery.
3. Can easily be used as work lights, potentially running off a separate battery, so your starter is safe.
4. More light when reversing.
5. Options for how much light (and current draw) you have when using them as work lights.
6. You can have them on permanently when driving forwards. But you must get out the cab to do this. You therefore can't do it by accident.
Bad bits:
1. Quite complicated to wire up.
2. Involves cutting into factory wiring.
What we did:
We originally had option 1 as work lights, with a switch in the back. But it was a pain to get out and turn them on and off when you needed them for reversing. So I basically never used them for that purpose. I did use them as work lights a few times but they were so bright that it was actually not very helpful. I could barely even look at the back of the car. I also wired them poorly the first time round and there was a bad voltage drop.
This unsuccessful attempt led to my development of option 5 as the best way to achieve the functions I wanted. I am very pleased with it, and use the lights far more as a result. How I actually did it is included in another post: Dual Purpose work/reverse lights.