Electrical Guru's

[SV_Dude]

I drew up this wiring diagram real quick to get an idea of how I'm going to wire up my 2x6 flood light to the rear of the 4runner. The idea is to remove the 3rd brake light and make a mold for the flood light to go into the third brake light spot. I want to be able to turn the flood light on so it is on constantly, and I also want to be able to turn it on so it only comes on when I put the 4runner into reverse. I'm not a wiring expert so someone please chime in and tell me if this diagram makes sense and if it would work... it makes sense to me but as I said, I'm no expert.

This is using a standard single pole double throw illuminated rocker switch:
Illuminated Surf N Turf Rocker Switches - SPST

 

[2ndGen4runner4x4]

You don't need to wire 2 relays in series like that. Just wire the reverse light relay to work off the tranny switch (whether its a hot or ground input).
Also - you dont need to control that relay from the toggle switch if its controlled fron the tranny switch.

 

[Iroke17]

i would just splice a wire from the original back up lights to it and then run a second wire to your flip switch
as for relays im sure someone will yell at me but i have never used one on any install and i have never had an issue with anything... ever 8 years.

 

[KidVermicious]

SV, I had aux lights on my '86 underneath - I tapped a power wire going into the reverse light and sent that to a relay, it worked well. I meant to run 12v off a cab switch to the same relay, but I never got around it. Would that be simpler than what you're planning up there?

 

[SparkEE]

i would just splice a wire from the original back up lights to it and then run a second wire to your flip switch
as for relays im sure someone will yell at me but i have never used one on any install and i have never had an issue with anything... ever 8 years.

Not to yell at ya or anything.. I use relays to isolate the additional load switching from the factory wiring which is notorious for being on the small side to begin with. The major issue is when significant loads are added to existing circuits with undersized wiring.

For this example though, one extra small light on the circuit shouldn't be a problem at all. As stated above, tap into the existing backup lights for the power. If you do that and have your cab switch from the battery (or other 12v source), your new backup light as well as the factory ones will light up when you throw it.

Good luck

 

[SV_Dude]

Thanks for the input guys. The intent with the two relays in series is to get clean power that isn't being used for anything else so I can maximize the potential of the flood light. Maybe it is a little over kill but it is also set up this way in case I want to add more rear lighting on the same circuit. I'm not sure if the factory wiring in the rear will handle 2 or 3 of these flood lights for continuous use. Also, I want the reverse lights to be on a switch so I can control when they come on and don't come on when in reverse. I don't want to blind people while in a parking lot or on a trail if it is hazardous to someone that may be directly in the light if I turn them on.

Kid: I'm not sure if there is an easier way or a more simple solution. The idea here is to get a dedicated fused power source to the rear of the 4runner to power the light and maybe more of these lights.

I'm still new to wiring so please continue to give me your input if there is a more common sense approach to this. I don't want to make this more complicated than it needs to be but I do want a dedicated power source ran to the rear for the lights and I want to be able to control the lights as described above.

 

[Iroke17]

ok since you you want them to aslo be on a kill switch i recommend you only run a flip switch and just activate them when needed to save your self alot more wiring
cause to be able to do what you want is to tap into back up lights run a wire all the way to the front hook to a switch run all the way back to lights again along with another cable to power them separately

 

[mikebontoft]

I'll just stick to what you asked. I'll draw up a diagram for you tomorrow (just quote or tag me so I don't forget). I do have to ask where your third brake light will be though. perhaps an led strip?

Anyway, the reverse switch is actually the simplest diagram I've seen for awhile . Just diagnosed a bad switch on my own so there you go.

-Tap into the outgoing wire near the switch. it's a simple 12v on/off positive only switch with the lights completing the circuit. this is your pin 85 on the relay.

-mount the relay wherever you choose. you'll have to run a good length of wire either way. I personally suggest near the switch. you'll see why.

- find a constant 12v supply from the harness that is just behind the cubby-hole on the driver's side. most of these control your wiper and window motors for the rear. They will be on a higher fused circuit because of this.... Note, however, I'd rather run a fused, dedicated wire if I could. Either way, this is your pin 30.

- ground pin 86 and your light bar. attach pin 87 to your light bar positive. it should operate now with your reverse lights only.

-now for your lighted switch. This is why I suggest a fused dedicated circuit. You can tap into the new circuit you made in the last step (remember, we are bypassing the relay this time.) OR create a new one directly in series with the switch to the lights... though that would add to the wires you need to run.

Anyway, to make sense of that, tap into the fused wire before the relay. the other side goes to your switch. Now from the switch, run a wire to pin 87 of your relay... (it should allow for a little less wire to be used.)

-note that you should be using an SPST switch, not SPDT as you have listed. you only need to have one circuit.

-verify your wiring is correct and that your lights will come on with reverse lights only with the switch off, and on their own without reverse lights.


OK SV, maybe I lost you there. My diagram should make perfect sense though when I post it.

For what it's worth, your diagram does work at least... though it's over complicated. On yours for example, to allow the reverse lights to trigger the light bar, you would have to keep the switch "on" in one direction, and "on" in the other to power it without the reverse signal. "off" would be a moot function.

Also, simplicity is reliability


edit: good lord is that long. Cell phone write-up ftw?

 

[mikebontoft]

well, now I see you DO want the option of completely disabling it. No worries, its a simple adjustment.

to use an SPDT switch, intercept your fused dedicated wire and hook it to the 12v input on the switch. run one side of the switch to pin 30 on your relay and continue as normal. The other side just wires up the same as I mentioned with the SPST switch (direct to pin 87)

Still simple, still reliable.

 

[SV_Dude]

ok since you you want them to aslo be on a kill switch i recommend you only run a flip switch and just activate them when needed to save your self alot more wiring
cause to be able to do what you want is to tap into back up lights run a wire all the way to the front hook to a switch run all the way back to lights again along with another cable to power them separately

Yes, that would be easier but I want to be able to have the lights not come on as I described above. I'm not trying to be stubborn, just different

well, now I see you DO want the option of completely disabling it. No worries, its a simple adjustment.

to use an SPDT switch, intercept your fused dedicated wire and hook it to the 12v input on the switch. run one side of the switch to pin 30 on your relay and continue as normal. The other side just wires up the same as I mentioned with the SPST switch (direct to pin 87)

Still simple, still reliable.

So you're saying that to do what I want, eliminate one relay in place of another switch? I would rather run everything off of one switch.

If that's not what you're saying then please draw me a diagram. I'm more of a hands on knuckle dragger kinda guy so seeing something is a lot easier to understand it than reading it.

 

[mikebontoft]

yeah I'll just draw it. it still uses one relay and one switch.

 

[mikebontoft]

here, it makes so much more sense here.

 

[SV_Dude]

The draw back to that is that the whole load of the light(s) are on that one switch. Most common switches aren't rated for that type of draw on them. The switches may hold up for a while but it won't be a reliable circuit.

 

[mikebontoft]

the switch you posted is rated at 21 amps. It's fine. When you get anything right at it's rated amperage, it's not going to be very reliable as you say. You can't possibly tell me that three relays and the extra wiring and connections are more reliable than a single switch and relay.

edit: I forgot to add that the orange is switched power but that's kind of obvious.

 

[KidVermicious]

Well, how much is a switch that IS rated for that type of load? Because Mike's drawing is exactly how I was thinking of wiring mine, but I don't wanna be burning out switches either...

 

[mikebontoft]

Just figure out the wattage you're going to be running. The LED work lamps are real low wattage. One I found would equate to 2 amps max. SV's probably isn't LED, but even then he would need to run 250 watts on a battery with 12v left on it to just about hit 21 amps.

There's plenty of switches at parts stores... most are between 15 and 30 amps. the nice one SV posted is $7 and you can buy from the link. that's about the average cost at a parts store anyway. ($7-8) Looking at the Dormans.

 

[SV_Dude]

I have never been a fan of running components off of a switch but Troy with treklights thinks that between the 3 lights (2 4" and 1 18"), the draw is less than 10 amps.

Mike... I think you made a believer out of me on this one.

 

[GonOvr]

ok... why even run the relay? you wouldnt even be using it for the purpose intended. Its not wise to switch power anyway. You should always switch a ground when possible.

Have you ever hooked the positive last on a battery and get a good spark? same rule applies on switches. You have a lot less draw through the ground side of a circuit since the resistor (accessory of any type) takes the hit.

This is why you hook up negative last. You can switch power, as long as you arent pulling a lot at once. This is why relays are important. You are only energizing the relay instead of the light and lettings the main power go through the relay instead of the switch. I personally switch ground. It is a lot easier on the circuit.

To use one relay and one switch

Put a diode between 87 and 87a in the direction that you want both lights on one way and one light on the other. This will let power go to both lights or just one depending on where the switch is.

You can also use your switch on 85 instead of ground and give the aftermarket switch a switched 12v from your headlights, parking lights, etc. That way the aftermarket lights will only come on while your parking lights or headlights are on.

 

[mikebontoft]

I agree that switched ground is more desirable.
the relay is necessary for the tap from the factory reverse lights. You could put a switch on the ground side of that and also the ground side of the light, but I figure that's 6-8 feet of ground wire just from the light.

 

[RAD4Runner]

SPDT Switch To Select Slave or Manual ON at Will

The draw back to that is that the whole load of the light(s) are on that one switch. Most common switches aren't rated for that type of draw on them. The switches may hold up for a while but it won't be a reliable circuit.

Happy New Year guys!

Regardless of switch current capacity, I would limit using switches to control circuit only and let relays handle loads which we might increase later (more, more lights please! ) I did it to my cranking circuit, and am currently doing H4 upgrade harness for my headlights (with DRL option).

So... this is how I will do my auxiliary reverse light:
(Tnx, mikebontoft, for the original schematic.)