Controlling another toggle switch with a tog switch
Okay so i am puttin a light bar on top of my roof but i am going to have it where i can take it off in 10 to 15 min max.Then i am going to hide the wire coming from the toggle switch running up to the roof.My question is that i dont want the end of the wire to still be hot if the toggle switch is off or on?Would it be hot still if the toggle switch is off?I am wondering if i added a extra toggle (underneath the hood) coming from the battery then connect the wire from the battery to the supply on toggle then run the load out to the toggle switch inside the cab.That way if someone accidentently hit the toggle inside the cab it wouldnt make sparks fly from my wire that is hide running to my roof alsong as i got the toggle switch underneath the hood off?
If the switch operates the relay and the switch is off, the leads should not be hot.
Not sure how many circuits you have up there, you can use an SAE connector with a cover if it is just a hot and ground, or a flat 4 trailer connector with a cover on it.


The SAE & Flat 4 connectors do not need covers on them, as the pins are in the rubber housing ( the ground is the exposed pin on both ).
The rubber cover might be nice so it does not scratch the truck where you are concerned about the wires touching the truck and arcing.
If you are thinking about the switch under the hood, which not just pull the fuse to the relay(s) ? That should be close to the battery on the install.
Not sure how many circuits you have up there, you can use an SAE connector with a cover if it is just a hot and ground, or a flat 4 trailer connector with a cover on it.


The SAE & Flat 4 connectors do not need covers on them, as the pins are in the rubber housing ( the ground is the exposed pin on both ).
The rubber cover might be nice so it does not scratch the truck where you are concerned about the wires touching the truck and arcing.
If you are thinking about the switch under the hood, which not just pull the fuse to the relay(s) ? That should be close to the battery on the install.
It's possible to wire the circuit so that unplugging the light bar will prevent any wire from being hot, even with the only switch turned ON, but there's no real reason to do it that way. Having an exposed hot wire up on the roof is no more dangerous than having 3-6 hot wires inside your trailer connector or a hot battery post under the hood. Just fuse it properly, and don't worry about it.
To make the circuit self-disabling at the roof connector, use the toggle to control a relay, but route the relay's trigger ground wire thru the roof connector back to the ground terminal for the light bar, so the relay can't come on if the light bar isn't plugged up.
To make the circuit self-disabling at the roof connector, use the toggle to control a relay, but route the relay's trigger ground wire thru the roof connector back to the ground terminal for the light bar, so the relay can't come on if the light bar isn't plugged up.
Last edited by Steve83; Nov 25, 2010 at 04:12 PM.
...<snip>.....
To make the circuit self-disabling at the roof connector, use the toggle to control a relay, but route the relay's trigger ground wire thru the roof connector back to the ground terminal for the light bar, so the relay can't come on if the light bar isn't plugged up.
To make the circuit self-disabling at the roof connector, use the toggle to control a relay, but route the relay's trigger ground wire thru the roof connector back to the ground terminal for the light bar, so the relay can't come on if the light bar isn't plugged up.
Great idea you got there
use the toggle to control a relay, but route the relay's trigger ground wire thru the roof connector back to the ground terminal for the light bar, so the relay can't come on if the light bar isn't plugged up
Trending Topics
This drawing I had 2 sets of lamps on different relays. If you only have 1 set of lights, omit the 2nd relay and the additional lead in the flat 4 connector ( have seen flat 3 connector online before )

As Steve83 posted, the relay ground is from the ground after the connector.
Once you unplug the connector, the relay coil(s) no longer have ground, you have them turned on or off, they no longer work.

As Steve83 posted, the relay ground is from the ground after the connector.
Once you unplug the connector, the relay coil(s) no longer have ground, you have them turned on or off, they no longer work.



