Wiring harness for auxiliary rear lights?

[emil77]

Hi guys,

I have a '72 Chevy C20 long bed. I bought a pair of the auxiliary driving lights pictured below that I would like to install on my rear bumper. I have never done wiring like this before, I have installed a car stereo one time if that counts. The kit does include a wiring harness, instructions and a switch. The thing that perplexes me is how do I get the wires all the way from the rear bumper up into the engine compartment? I don't understand the routing of the wires part. I have googled and read up on the subject, but still don't get it. Do I really have to run the wires all the way from the rear up into the engine compartment to hook onto the battery?

[Andy4639]

That depends on how you want them to work. If you have the backup lights working you can tie into your harness under the truck are behind the light it self and ground them. They will only come on when the truck is in reverse though.
If you want them to work anytime you will need a wire from the battery to switch on the dash to the lights on the back bumper.
It all depends on how u want them to operate.

[piecesparts]

You should only have to run one wire from the engine compartment to the rear of the truck. Use a quality wire and size it, so that you don't overload it. I would suggest at least a 14 gauge wire, I personally would use a 12 gauge, but I am a tad bit overconcious when I do things like this. I personally would also use wiring protection like a convuluted wire loom. Take the wire along the inside of the frame to the front of the firewall and feed it into the cab (good idea to put a rubber grommet around the wire at the hole in the firewall) and to the point where you will have your switch for the lights. At that point cut the wire and connect to the switch. Now you will have to feed another wire to a power source, preferrably to the battery positive post, so that you do not ovverload some other circuit in your truck. Before connecting to the battery post or terminal close to the battery put an in-line fuse into the circuit close to the battery. This way you have protection, in case the wiring or lights go to ground and that way you do not burn up the whole wire and possibly the truck. The size of the fuse should be large enough to handle the lights and not too large to allow for melting of the wire in cse somehting happens.

The lights on the back of the truck should ground to the frame for the negative part of the circuit. Ensure that you have a good clean spot for the bolt or ground wire to connect to. I would go behind the bumper and find a spot to clean off and mount a bolt through the frame.

[MikeyMan]

I did the rear driving lights and love it! Really lights up everything behind you.

I used an old power cord from a broken shop vac. You could also use an old extension cord. The vac cord I used was 2-conductor 14 gauge wire. It's already insulated and jacketed, so I just ran it along the frame rail next to the rear tailight harness and fastened it with zip ties. I used one wire for an extra ground, and the other for the hot. My relay is on the firewall, and I have a toggle switch under the dash.

The reverse lights weren't working due to Trans and shifter swaps anyway. So, I tapped the backup lights feed at the firewall and tied it to the relay. I have to manually turn them on via the toggle switch under my dash. The relay feeds the original backup lights through the green wire in the rear harness, and the auxiliary lights through the 14 gauge vac cord.

[emil77]

Thanks for the help guys. Now I am thinking of using the rocker switch below. The only problem is that I have to cut a hole in the dash to install it. Is there any other way I can install this switch without making a hole in the dash?

https://otrattw.com/proddetail.php?p...SCZL-1ZL&cat=5

[Ol Blue K20]

On a side note, in Cali you have to have covers over them if they are seperate from back up lights, some cops use them as an excuse to pull you over

[kcsa75]

Originally Posted by emil77

Thanks for the help guys. Now I am thinking of using the rocker switch below. The only problem is that I have to cut a hole in the dash to install it. Is there any other way I can install this switch without making a hole in the dash?

https://otrattw.com/proddetail.php?p...SCZL-1ZL&cat=5

Were it me, I would you a switch like this.
https://otrattw.com/products.php?cat=10

Not nearly as big of a hole in the dash, costs less and it seems more period-correct. If your truck has been around the block as many times as mine, you might already have a hole on bottom of the dash that will work.

[MikeyMan]

Originally Posted by emil77

Thanks for the help guys. Now I am thinking of using the rocker switch below. The only problem is that I have to cut a hole in the dash to install it. Is there any other way I can install this switch without making a hole in the dash?

https://otrattw.com/proddetail.php?p...SCZL-1ZL&cat=5

You may be able to use an "L" shaped bracket or piece of sheetmetal to let that switch hang below the dash. This way, you only need 1 or2 screws into the underside of the dash to mount it.
I have this cool looking tripple toggle switch bank that hangs under my dash next to the emergency brake release. I took a 5 inch wide L shaped bracket and cut out the middle to let the switch contacts poke through. Then I fastend the switch bank to the L bracket, which screws up into the underside if my dash.
I have also mounted the single toggle switches with 1/2" round hole. Those I just drilled the underside of the dash near the ignition switch. Also have drilled into face of dash near the headlight switch. Just be careful to have clearance and no wires behind where you drill.

[MikeyMan]

Originally Posted by Ol Blue K20

On a side note, in Cali you have to have covers over them if they are seperate from back up lights, some cops use them as an excuse to pull you over

Another excuse to get hassled by Johnny Law.

I was wondering if there are any laws regarding this set up.

[MikeyMan]

Originally Posted by kcsa75

If your truck has been around the block as many times as mine, you might already have a hole on bottom of the dash that will work.

Yeah, I've found holes there too.

All kinds of accessories swiss cheesed up my many trucks.
Horn button, fog lights, backup lights, interior lights, and of course the fan blower switch to bypass the broken factory one!

[piecesparts]

Originally Posted by emil77

Thanks for the help guys. Now I am thinking of using the rocker switch below. The only problem is that I have to cut a hole in the dash to install it. Is there any other way I can install this switch without making a hole in the dash?

https://otrattw.com/proddetail.php?p...SCZL-1ZL&cat=5

They make brackets for rocker switches that mount under the dash.

[emil77]

Originally Posted by piecesparts

They make brackets for rocker switches that mount under the dash.

Thanks for all the help guys.

What do they call those brackets? I've tried Googling but I am probably using the wrong search terms.

[emil77]

Bump.

[MikeyMan]

Check out your local auto parts store.

I've seen switches and holders at Pepboys, O'Riellys, and even Walmart.

You might want to buy a different style of switch if you can't find a way to mount your current rocker switch.

[piecesparts]

Yep just go down to the local parts shop and they should have them on the rack

They call them switch holders or even just brackets