Switchable Aux Reverse Lights - Schematic Feedback Requested
JK Freak
Joined: Apr 2009
Posts: 579
Likes: 1
From: Westchester, NY
As I was running a 3 relay solution around my head, trying to map out how I was going to control two relays with a third, it made me realize that I was over-thinking the task at hand and the solution was actually quite simple. Not sure why I didn't think of this in the first place, but sometimes that's how the process goes. I present to you...the KISS schematic. 
It's comprised of simply two SPST relays. One triggered by the reverse circuit and the other triggered by a switch. 
As shown, the switch controls the positive side of the control circuit. I personally prefer to switch the negative side but I know a lot of people prefer the positive side so that's how I drew it.
As a side note, I was fortunate enough to get a look at the factory wiring for the reverse lights and it appears the power wire for them runs from a relay in the TIPM all the way back to the lights. This means that tapping the reverse wire can be done anywhere along that path...at the tail lights, in the tub, or in the engine compartment. I did have another member tell me in a different thread that he traced the reverse wire from the tail light to the front of the tub and it was no longer 12v. Apparently, he was looking at the wrong wire.
It's comprised of simply two SPST relays. One triggered by the reverse circuit and the other triggered by a switch. As shown, the switch controls the positive side of the control circuit. I personally prefer to switch the negative side but I know a lot of people prefer the positive side so that's how I drew it.
As a side note, I was fortunate enough to get a look at the factory wiring for the reverse lights and it appears the power wire for them runs from a relay in the TIPM all the way back to the lights. This means that tapping the reverse wire can be done anywhere along that path...at the tail lights, in the tub, or in the engine compartment. I did have another member tell me in a different thread that he traced the reverse wire from the tail light to the front of the tub and it was no longer 12v. Apparently, he was looking at the wrong wire.
Thread Starter
JK Junkie
Joined: Nov 2013
Posts: 3,703
Likes: 8
From: The Dirty South
Since the power to the aux lights is in no way connected to the oem wiring I'm not sure how that would be possible. But Chris will find out this weekend.
JK Freak
Joined: Apr 2009
Posts: 579
Likes: 1
From: Westchester, NY
My thinking is that triggering 87 will power 85, the same way triggering 85 powers 87. But I don't know if it works like that.
Thread Starter
JK Junkie
Joined: Nov 2013
Posts: 3,703
Likes: 8
From: The Dirty South
Inside the relay pin 85 is connected to pin 86 via a coil. Pin 30, when the coil is energized, is connected to pin 87. It's kind of like a reed switch they use in house alarms. The coil is the equivalent of the magnet when energized and it pulls the switch between 30 and 87 to either make or unmake the connection, depending on whether it is a normally open or normally closed switch. The magnet does not physically contact the switch.
JK Freak
Joined: Apr 2009
Posts: 579
Likes: 1
From: Westchester, NY
Inside the relay pin 85 is connected to pin 86 via a coil. Pin 30, when the coil is energized, is connected to pin 87. It's kind of like a reed switch they use in house alarms. The coil is the equivalent of the magnet when energized and it pulls the switch between 30 and 87 to either make or unmake the connection, depending on whether it is a normally open or normally closed switch. The magnet does not physically contact the switch.
Thread Starter
JK Junkie
Joined: Nov 2013
Posts: 3,703
Likes: 8
From: The Dirty South
JK Freak
Joined: Dec 2011
Posts: 586
Likes: 1
From: Okinawa, Japan
Let me first say that because 14Sport already put so much work into this, I'm going to wire it up per the schematic and test it out.
However, what's kind of funny/ironic is that after all this toying around with the schematics I'm probably going to end up keeping them operated by switch only in the long run and not tie them in to my reverse lights. Reason being is the lights I ordered for this weekend's install are the 60 degree 18w LEDs (same as I run on my front bumper). They're pretty damn bright and certainly overkill as a regular reverse light. Plus I'll be mounting them up sort of high on my tire-carrier. I think I'd be inviting a cop to write me a ticket if I had them come on every time I threw the vehicle in reverse, not to mention the hate and discontent I'd cause the unsuspecting driver that happened to be in my rear path at night and got blinded. I'll probably wire them into a separate stand-alone switch and only flip them on when I absolutely need to.
Like I said before though, I'm definitely going to test out this schematic first just to see it work. I already have the relays and all the wiring, and frankly it won't be that much more work to wire it up and test it out. What I'll probably do is wire it all up to test it out, but then unplug the reverse tap from the relay to inactivate it. Of course I'll plug/tape off the ends to prevent a short. If I ever decide to go with smaller reverse lights in the future and want them wired into my reverse switch, I'll already have all the wiring ran. Will just need to remove the tape and plug that tap back into the relay... done!
Weekend's here. Time to work on a mounting solution for those lights. Home Depot here I come!
However, what's kind of funny/ironic is that after all this toying around with the schematics I'm probably going to end up keeping them operated by switch only in the long run and not tie them in to my reverse lights. Reason being is the lights I ordered for this weekend's install are the 60 degree 18w LEDs (same as I run on my front bumper). They're pretty damn bright and certainly overkill as a regular reverse light. Plus I'll be mounting them up sort of high on my tire-carrier. I think I'd be inviting a cop to write me a ticket if I had them come on every time I threw the vehicle in reverse, not to mention the hate and discontent I'd cause the unsuspecting driver that happened to be in my rear path at night and got blinded. I'll probably wire them into a separate stand-alone switch and only flip them on when I absolutely need to.
Like I said before though, I'm definitely going to test out this schematic first just to see it work. I already have the relays and all the wiring, and frankly it won't be that much more work to wire it up and test it out. What I'll probably do is wire it all up to test it out, but then unplug the reverse tap from the relay to inactivate it. Of course I'll plug/tape off the ends to prevent a short. If I ever decide to go with smaller reverse lights in the future and want them wired into my reverse switch, I'll already have all the wiring ran. Will just need to remove the tape and plug that tap back into the relay... done!
Weekend's here. Time to work on a mounting solution for those lights. Home Depot here I come!
Thread Starter
JK Junkie
Joined: Nov 2013
Posts: 3,703
Likes: 8
From: The Dirty South
Let me first say that because 14Sport already put so much work into this, I'm going to wire it up per the schematic and test it out.
However, what's kind of funny/ironic is that after all this toying around with the schematics I'm probably going to end up keeping them operated by switch only in the long run and not tie them in to my reverse lights. Reason being is the lights I ordered for this weekend's install are the 60 degree 18w LEDs (same as I run on my front bumper). They're pretty damn bright and certainly overkill as a regular reverse light. Plus I'll be mounting them up sort of high on my tire-carrier. I think I'd be inviting a cop to write me a ticket if I had them come on every time I threw the vehicle in reverse, not to mention the hate and discontent I'd cause the unsuspecting driver that happened to be in my rear path at night and got blinded. I'll probably wire them into a separate stand-alone switch and only flip them on when I absolutely need to.
Like I said before though, I'm definitely going to test out this schematic first just to see it work. I already have the relays and all the wiring, and frankly it won't be that much more work to wire it up and test it out. What I'll probably do is wire it all up to test it out, but then unplug the reverse tap from the relay to inactivate it. Of course I'll plug/tape off the ends to prevent a short. If I ever decide to go with smaller reverse lights in the future and want them wired into my reverse switch, I'll already have all the wiring ran. Will just need to remove the tape and plug that tap back into the relay... done!
Weekend's here. Time to work on a mounting solution for those lights. Home Depot here I come!
However, what's kind of funny/ironic is that after all this toying around with the schematics I'm probably going to end up keeping them operated by switch only in the long run and not tie them in to my reverse lights. Reason being is the lights I ordered for this weekend's install are the 60 degree 18w LEDs (same as I run on my front bumper). They're pretty damn bright and certainly overkill as a regular reverse light. Plus I'll be mounting them up sort of high on my tire-carrier. I think I'd be inviting a cop to write me a ticket if I had them come on every time I threw the vehicle in reverse, not to mention the hate and discontent I'd cause the unsuspecting driver that happened to be in my rear path at night and got blinded. I'll probably wire them into a separate stand-alone switch and only flip them on when I absolutely need to.
Like I said before though, I'm definitely going to test out this schematic first just to see it work. I already have the relays and all the wiring, and frankly it won't be that much more work to wire it up and test it out. What I'll probably do is wire it all up to test it out, but then unplug the reverse tap from the relay to inactivate it. Of course I'll plug/tape off the ends to prevent a short. If I ever decide to go with smaller reverse lights in the future and want them wired into my reverse switch, I'll already have all the wiring ran. Will just need to remove the tape and plug that tap back into the relay... done!
Weekend's here. Time to work on a mounting solution for those lights. Home Depot here I come!
JK Freak
Joined: Dec 2011
Posts: 586
Likes: 1
From: Okinawa, Japan
Seriously, not a big deal. I want to run the wiring for possibly future use anyways. I'm pretty certain I'll end up going with smaller LEDs in the future. May as well run the the wiring now will I'm in there. I'll let you know how it goes.
Thread Starter
JK Junkie
Joined: Nov 2013
Posts: 3,703
Likes: 8
From: The Dirty South
