I got some knock off Truck Lites for xmas this past year and I've been getting flashed during early morning drives into work. I think it's time to tackle the reduced voltage high beam daytime running lights that came on my Jeep that originated in Canada. I've heard many times that you just need to cut "X" wire and it will solve all your problems but I wasn't satisfied with that and wanted to know what I was cutting and why. I'll attach snippets from the factory service manual below to help anyone else in my position better understand the why behind the how. I don't claim to be a ASE master tech or anything but I can feel my way through a wiring diagram with a little help from the service manual itself.
We'll start at the DAYTIME RUNNING LAMP DIAGNOSIS page from the FSM (Factory Service Manual).
You can see in the above image how to diagnose DRL's that aren't working. Not really what I wanted but it points us in the right direction, Group 8W of the FSM.
Page 8W - 50 - 2 of the FSM shows the overall front lighting diagram.
In the above diagram I believe the upper reference to the DRL Module is just showing where the module is getting power from. The lower module gives us a little more info. You can see that pin 1 on the module ties into the high beam circuit through Splice S105. At the low beam output of the HEADLAMP DIMMER SWITCH you can see Splice S104 which appears again on the DRL diagram below. I believe this tells the module to essentially stop the DRL output. I believe that none of the wires on this diagram do us any good to disable the DRL's as when the module see's an issue like being unplugged it disables your high beam indicator. I want mine to function correctly.
The diagram also leads us to page 8W-50-8 for further info on the module itself.
In the above diagram you can see that there are in/outputs for both high and low beam, pins 1 & 10. I don't think we want to mess with either of those, nor do we want to mess with the ground or switched power. This leaves up pin 7 VEHICLE SPEED SENSOR SIGNAL. If we either disconnect or cut this wire the DRL module won't get a signal from the speed sensor and should never turn on your DRL's again. On my Jeep this should be a white wire with an orange trace and should be easy for even my colorblind self to identify as there are no other white wires going to the DRL Module. And I just went out to the Jeep at lunch and cut the wire and no more DRL's.
Below I'll attach some reference images from the FSM that helped me understand these diagrams along the way.
We'll start at the DAYTIME RUNNING LAMP DIAGNOSIS page from the FSM (Factory Service Manual).
You can see in the above image how to diagnose DRL's that aren't working. Not really what I wanted but it points us in the right direction, Group 8W of the FSM.
Page 8W - 50 - 2 of the FSM shows the overall front lighting diagram.
In the above diagram I believe the upper reference to the DRL Module is just showing where the module is getting power from. The lower module gives us a little more info. You can see that pin 1 on the module ties into the high beam circuit through Splice S105. At the low beam output of the HEADLAMP DIMMER SWITCH you can see Splice S104 which appears again on the DRL diagram below. I believe this tells the module to essentially stop the DRL output. I believe that none of the wires on this diagram do us any good to disable the DRL's as when the module see's an issue like being unplugged it disables your high beam indicator. I want mine to function correctly.
The diagram also leads us to page 8W-50-8 for further info on the module itself.
In the above diagram you can see that there are in/outputs for both high and low beam, pins 1 & 10. I don't think we want to mess with either of those, nor do we want to mess with the ground or switched power. This leaves up pin 7 VEHICLE SPEED SENSOR SIGNAL. If we either disconnect or cut this wire the DRL module won't get a signal from the speed sensor and should never turn on your DRL's again. On my Jeep this should be a white wire with an orange trace and should be easy for even my colorblind self to identify as there are no other white wires going to the DRL Module. And I just went out to the Jeep at lunch and cut the wire and no more DRL's.
Below I'll attach some reference images from the FSM that helped me understand these diagrams along the way.
