Hey I am getting a light bar installed on the roof.

2015 ddrt

I am looking to have it tied to 2 switches. One for constant on off.

And the other I wanted to tie into the auto dim high beams so that when a car comes it will shut the light bar off aith the high beams. I was wondering if anyone had any information on this.

I don't beleive it should be an issue it should be as simple as running a fuse tap wire from the high beam fuse to a relay then to the light.

This should mean that when I turn on on switch, as the auto high beams come on it sends power to the relay then to the light bar. And when I turn the other switch on It send power straight to the light bar.

I need thoughts and opinions as my install is booked for tomorow.

 

So are you wanting this where the light bar only works when the high beams are on but you can choose whether or not the light bar is on when the high beams are on, then have the light bar automatically turn off when the auto high beams dim the headlights? Or are you wanting the ability to control the light bar regardless of high beam use, but also be able to select to have it controlled by the high beams? Or are you wanting to be able to control the the light bar with a dedicated switch as long as the auto high beams are not dimmed?

The first scenario is pretty straight-forward using the relay with the relay coil powered by the high beam circuit through a series SPST switch. The second scenario will be a bit more involved, but should be pretty easy with a SPDT switch with the center terminal of the switch connected to the relay coil, one "throw" connected to battery voltage, and the other "throw" connected to the high beam fuse. The final scenario will require a bit of logic and at least a diode to prevent back-feeding the high beam circuit when you want full manual control of the light bar. But Boolean logic (NAND gate and possibly more, or something like an Arduino) would be required to force the bar off when the high beams dim even if you have the switch set for manual control.

I wonder if a large lightbar on the roof may put off enough light that it would cause the auto highbeam circuit to fail to work correctly anyway though.

-Rod

 

So basically I have an eight panel switch, each with on off buttons.

Closest to number 2 but I don't want to run a 3 way switch (as I already have an eight button switch pack)

I want one switch to control the light bar independently of the high beams giving me an on off function regardless of if the high beams are on or off.

I want the second switch to tie the light bar to the high beams, so when they come on the switch also comes on, and when they dim the light bar shuts off.

Ideally with the constant on off able to overide the high beams if both are turned on.

I'm not going to be doing the install myself but I am mostly looking for information to pass onto the tech doing the installation.

the switch will also be controling led strip lights and rock lights and eventually backup lights.

I was also thinking the light bar might be right enough to make the auto dim feature not work anyways but I am not 100% sure if that will be an issue, ive been looking for someone else that has done this but i can not seem to find anyone.

I had figured so long as the light bar is pointed up enough to not hit the sensor it should not cause an issue and then it wpuld be a matter of just finding the right angle where it would still light up the road but not hit the sensor.

If it matters at all, all the products I have are Auxbeam brand rgbw light bars and switch pack, I can link product info if needed.

 

Does your Durango R/T have the HID headlights? If so, this might be a bit more challenging. Those have a "driver" signal for the high beams from the BCM so I'm not sure if it's a 5V logic level or regular 12V.

-Rod

 

The wiring diagrams for the non-HID Durango also refer to the lines as "drivers" so I'm going to assume that's still a 12V signal. I've sketched out a quick and dirty method that should work fine. In addition to your switch panel and light bar you'll need some wire, a SPST or SPDT automotive relay, an inline fuse rated for your light bar current draw, and 3 rectifier diodes. The typical part number for such a diode is a 1N4001 through 1N4007. Any of those should work fine for automotive voltages.

Wired up this way you'll have control over the light bar when the vehicle is in either Accessory mode or Run (Run would be ideal to prevent draining the battery, but Run only signals are not as easy to find typically). The Constant switch will activate the relay and turn on the light bar. The Hi-beam Controlled switch will activate the relay if the Constant switch is off and the high beams are powered. The diode before the Constant switch will prevent the high beam circuit from back powering the Run/Accy circuit when the high beams on are if the Constant switch is closed, and similarly the diode before the Hi-beam Controlled switch will prevent the Run/Accy circuit from activating the high beams if both the Hi-beam Controlled switch and the Constant switch are closed at the same time. The reverse-biased diode at the relay is to shunt power when the relay opens.

It's not critical whether the diodes are placed before or after the switches, but I figured it would be easier to tie the outputs of both switches together and to the relay if the diodes were not on that side of the switch. But maybe it's easier to use the Constant diode as a jumper wire between the two switches, and that would be acceptable.

-Rod


Light bar dual switch circuit

 

you

I'll pass this onto them and talk to them about doing this i would LOVE to have then hooked up this way.

As is they refused to do it and told me they werent willing to drill holes to mount the light bar woth the mounts i have...

But to my knowledge ANY mounting brackets to have for the durango will have to be drilled for the durrango as there is not any holes to mount and in order to do a roof rack you have to use rivnuts... so i may be looking for another shop.