Hi guys,
I have installed an LED light bar on my neighbors truck and would like to be able to connect them to come on with the high beams.
The truck is a 2001 2500 diesel with single lens headlights (non sport), Canadian model with DRL ( unplugged at the moment)

I do not want to get into any legal conversations.
This truck uses the hi/low switch to provide ground for the hi and low beams in a 9004 configuration, so there is power provided to terminal A and B is for Low beam and C is for hi beam.
When the truck is off there is 12.6 volts available at all wires as there is no ground being provided at the time.
My question is, "has anyone successfully installed a light bar to come on with the hi beams?"
I have searched and not found what I was looking for so I have come to the forum to find an answer. If this has been addressed, please direct me to the correct thread.
Thanks for any help you can give.

 

The headlight switch may not be happy with an additional load..... so, using relays is going to be the hot ticket. If the switch provides ground path for the circuit, simply tap into it, and use it as the ground for the relay control circuit, and have the relay provide power to the lights.

 

I have tried to do that but it doesn't seem to want to cooperate. I am wondering if there is something else going on with this truck in the headlight circuit.
With the DRL plugged in the hi beam indicator stays on all the time when the lights are on and the light bar comes on no matter what position the selector is in. DRL unplugged then the light bar doesn't come on at all!!!! This one has me a little perplexed at the moment!
I wanted to know if anyone has made this work or if I have a secondary issue with the DRL. I don't have access to another one right now so I may have to wait till I can get a known good one.
Thanks for the reply.

 

Download the 01 service manual from here. Wiring diagrams are in section 8W. have a look there, and see what you think. DRL's do indeed make life complicated.

I thought the newer trucks (98 and up) had the headlight switch providing power though???? No?

 

Thanks Hey You,
The switch sending power to the lights started in 2002 or 2003 if my info is correct. This truck still uses the selector to provide ground.
DRL may screw up anything I am trying to accomplish in the following.
The wiring diagram in the manual is what I needed. It looks like I can switch my secondary hi beam/light bar relay by getting the signal power (86) from the high beam power wire and use the switched hi beam grounding wire for the negative (85). That way when the hi beam lights are off there will be 12 volts on both sides and it will shut the relay off. i will use power from the PDC to pin 30 and energize the light bar with 87 thru a diode to prevent any back feeding. Will have to test this theory tomorrow when I can get the truck back. I will post my findings.
Happy Mothers day out there!

 

Get a four post relay.

85 to ground.
86 to one of the high beam wires. I used the driver side so I could mount the relay to the battery tray.
30 to battery hot.
87 to light bar hot.
Light bar ground to ground.
After I connected the relay I gooped liquid electric tape all over the terminals to keep them corrosion free.

I have my bumper lights and my horns wired like this and they work as expected with the load going from the battery, through the lights and on to ground without going through the pdc or the headlight switch.

 

Hi Sherrif420,thanks for the info.
I tried that way originally and due to the headlight wires all having 12.6 volts on them with the lights off, the grounding wire at 86 that you mentioned will keep the light bar on when the truck or the lights are turned off.
Again, I am not 100% sure that I am still fighting a DRL issue as well, which may be giving me a bunch of false results.

 

Headlamp switch does indeed provide ground path for the headlights. Violet w/white trace wire.

 

I have 2 rigid dually lights that turn on with the fog light function on my OE headlight switch. I just connected the original fog light power to a relay. The relay then powers the light pods.
Good tip when using relays is to get the pre-wired relay sockets. Then just solider/heat-shrink the wires to the correct places on the socket pigtails. Makes for a clean install!
Also, for some reason when the rigid lights are on, the high beam indicator on the dash is slightly illuminated.

 

I just went and looked. The bumper lights (55 watt x 2) are connected to a headlight harness and plugged into the driver side because I have one of the LMC harnesses running my headlights and it's plugged into the passenger side. So my ground for the bumper lights is coming from the driver headlight plug since the headlight switch only runs the bumper lights and two relays for the headlights.

So it's wired like I said before with the only difference being that the ground is the ground on the headlight plug.

If you're going to run the 100/80 watt bulbs like I am then you'll want to think about getting the LMC headlight harness because the higher wattage bulbs along with whatever the light bar is pulling will cook a headlight switch pretty quick.

FYI - The higher wattage bulbs are worth it. They're labeled as offroad bulbs by Hella but they don't blind people like all the people running LED lights in stock housings so I don't pay any attention to the off road only rating. My 2015 Mustang with HID lights aren't as bright as the lights on my truck.