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Need relay wiring help please

3K views 13 replies 3 participants last post by  brandofamily 
#1 ·
I have a set of aux led backup lights that are currently triggered by the reverse light stock harness. I would like to keep that trigger but set them up with a relay so I can turn them on with a switch from the driver compartment.
Can anyone give me a diagram of how to do that?
The power for the switch will come from an Apollointech switch box.
Thanks
 
#2 ·
Generally, use a five pin relay, one with a normally closed (NC) center and run it so that the NC works as currently wired, then wire your alternate switch to the energized relay function.

Relays are easy and fun!
5 pin relays provide 2 pins (85 & 86) to control the coil and 3 pins (30, 87 & 87A) which switch power between two circuits. They have both normally open (NO) and normally closed (NC) connection pins.

Add the 5 pin relay outside of the switch box to be triggered by your switch box - i.e. a relay triggered by the switch box relay.
NC to your current backup light trigger (always triggered by reverse)
activated/energized relay pin to your switch to manually trigger the lights.

You might need to check a wiring diagram to trace the backup light wire to its closest location under the hood. this is the only difficult part, as this is where you would splice the new relay.

One other possible concern is if that backup light circuit is on the CAN bus (if you have automatic?) then you would splice into the wire coming from the switch on the transmission which triggers the REVERSE / backup lights to come on.

CAN bus triggers can be fun. For example, the horns are now also on the CAN bus, as I found out when trying to wire in my air horns to activate off the steering wheel horn activation. I just used a 5 pin NC relay on one of the two horns and it works well.


The CAN bus issue is only about where the voltage comes from to power the lights.
If you have CAN bus issues, then the 5 pin might be spliced in somewhere near the rear bumper where you already have an active 12v source. The relay would then just divert power to the lights from there.

Worst case is to make those aux lights independent of the reverse so that if you need them you can activate them when you like, and then no other relay is needed, just wire the lights to your switch.

And whether you use a NC or Normally Open (NO reverse wiring logic) is up to you, whether your relay energizes the power line or shorts an open ground to ground. Be creative!
 
#3 ·
You sure sound like you know what you are talking about... I understand the concept of the relay, unfortunately I lost you in the execution. Any chance you could do a drawing/ diagram or point me to a diagram of which wire needs to run to which pin?
Let's assume I am mounting the relay at the rear in the tailight cavity. Thanks.


Edit: I found this diagram, but not sure if it executes what I want... replace Dome Supervisor w/ "tail light harness wire", replace "rock lights" w/ "back-up lights"... I think. Not sure if I'd need to run a battery wire to the back as well as an spod wire too of if there is a power source for the relay back there already. Would the "constant on" rear power port wire be sufficient to power the relay as the battery source?
 
#4 ·
See the attachment for a more simplified approach.
 

Attachments

#5 ·
Thank you.

So leave what I have and run another power wire thru the relay to the power feed for the lights.
I assume Amazon has relays w/ diodes built in.
I need to run one wire to back of Jeep from 87 to 12+V that is already connected to lights, correct?


Edit: I have a few 5 pin relays that show the same "diode" diagram on them from 85 & 86 to 30.... do I just leave the 87a w/ no wire?
Also, I see on your diagram it says backup lights and aux lights will illuminate with the switch. Any easy way to only have aux lights illuminate with switch?


2nd Edit... the Spod already has the relay you have pictured built into the box... do I need a 2nd relay?
 
#8 ·
This is the way I wired mine. Allows always off, on with switch, or on when in reverse.

Nice!
Only thing is OP already has an existing circuit installation he wants to modify.
 
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