Back-up light power source??

[.44 mag]

I haven't gotten a shop manual for this rig yet. I was wondering if someone could tell me if the hot lead in the wireing harness to the trailer connector would handle the amp draw of a couple driving lights out the back? What I want to do is tie into the back-up light circuit to trigger a relay and power a set of 55 or 100 watt lights off a separate fused power supply. I was just trying to think if there was another way other than running a hot lead all the way back from the battery.

Thanks for any input!



Hank

 

[SLang]

A bosch style automotive relay pulls about 1/4A. Any circuit including you dash light circuit will handle this.



100W lights pulls around 8. 33A. You should run a seperate 12 Ga. wire from your battery with a 10A fuse on it. 10A will be to much of an addition for any circuit in your truck.

 

[snake]

If you have a 7 pole plug for your trailer, the center one is hot all the time. It should be all right put a fuse in it, use 12 or 14 Ga. wire.

 

[Thomas]

I'm with SLang on running a separate circuit to the back. I put in 8 gauge wire to a box at the rear for various add-ons, including 220 watts worth of backup light.



However, your question was about using the 12 volt B+ in the tow package. Fuse 8 (40 amps) in the PDC supplies 12 volt B+ in the tow package via 12 gauge wire. Fuse 8 also supplies the juice to the trailer brakes.



The center pin on the 7-pin socket supplied as part of the trailer tow package is the back-up lamp feed—directly from the switch via 18 gauge wire—on model year 2000. I doubt that it's diffrerent on your model year 2001.

 

[.44 mag]

Thanks guys!



I thought it would be smarter to just run another wire back, but I thought there might be an easier way around it.



What type lights are you guys running?



Hank

 

[pcorssmit]

That is just how mine are wired. I have a pair of 55 watt backup lights (Navigator? got them at Camping World, I've heard Pep Boys had them too) mounted between the trailer hitch and the rear bumper, best place I could find for good protection. They are powered by a relay, the hot is from the trailer B+ and the switched wire is the reverse light wire in the trailer harness. The relay is mounted up on the cross member behind the spare. Works out real well. As stated above, the wire is on a 40 amp fuse under the hood. I cut out a plate that fits over the trailer hitch, then welded it to the hitch and bolted the lights to it, pointing out slightly. Now I can see what I'm backing over at night.



Pete

 

[Thomas]

Here is a good thread on backup lights:



Backup Lights



I,m running the Hella 90601's—2 H3 bulbs (55 watts each) per lamp X 2 lamps = 220 watts to the rear. Great work lamps as well as backup lamps.

 

[Midnite]

Hmmm... I was going to wire my 55 watt light through the backup light circuit, but I ended up wiring up a separate circuit with its own switch.



My reasoning was that if I was by myself and needed the extra light to either hook up a trailer or do some other work where I was out of the cab standing behind the truck, I would have to leave the truck in reverse and engage the emergency brake if it was wired up to the backup light circuit. That's something I'm extremely uncomfortable with--I bet my life on *very* few things, and the odds of my emergency brake failing at the wrong moment is NOT one of them.



The only down side is that if I'm backing up and want the extra light, I have to flick a seperate switch, but that's no big deal.



Mike

 

[Thomas]

Those of us with 4X4's need only put the transfer case in neutral with the transmission in reverse—no special switch needed.

 

[Midnite]

Originally posted by Thomas

Those of us with 4X4's need only put the transfer case in neutral with the transmission in reverse-no special switch needed.

Well, again--if you're on a steep enough grade you may very well be betting your life or someone elses (or maybe just the neighbor's car, but that's bad enough) that your emergency brake won't fail. I've been on a couple of hills here in Anchorage that were steep enough that my emergency brake wouldn't hold the truck. Yeah, you could also chock the tires, but that's a lot of work just to avoid having to flick a switch.



Mike

 

[EMDDIESEL]

I ran a 10 gauge wire from a relay in the engine compartment right next to the driver side battery to the rear bumper for the lights. This way, the positive wire has no current unless the lights are on. I have the backup lights operated by a switch so this way i dont have to be in reverse to use them. Convienient for hooking up a trailer or blinding the moron behind you with the brights on.

 

[Midnite]

Originally posted by EMDDIESEL

Convienient for hooking up a trailer or blinding the moron behind you with the brights on.

Heheh... I love it! What kind of lights do you have on the rear bumper?



I got mine at NAPA--they have a rubber housing, 55 watt, and were only about $10. Probably not real good for blinding morons, unfortunately.



Mike

 

[Shovelhead]

With my luck the "moron" behind me would be a state trooper

 

[EMDDIESEL]

I have the Hella driving lights, they work ok, i want something brighter though.

 

[DieselDoghouse]

Wiring backup lights

Having now painted a large bullseye on my, err. I think you definitely need to source anything as hefty as driving lights from separate power. The stock B/U circuit is only 10A and in my case with the halogen bulbs in the 3157 sockets we're at 8. 0 amps already. The auxiliary lead in the 7-way connector feeds from a healthy 40A auxiliary fuse in the PDC. Therefore, here's what I did: 1. carry the B+ (aux), ground, and B/U (as a switching lead) out thru a 7-way plug to a 4-pin flat connector (because of the current rating versus a molex connector or like).

2. the 4-pin carries the harness to a weathertight frame-mounted box with an overload fuse and a 30A relay.

3. The relay output is 'hard wired' to the auxiliary lights.

You can break the harness at the trailer 7-way and the 4-pin plug for trailering purposes since you're not likely to need the extra backup lights then, and you don't leave and dangling harnesses. Drop you hitch, reinstall the harness and you have the lights back without modifying the DC harness! At least this works for me.

 

[paccool]

Did mine the same as EMDDiesel except I tied the relay into the backup light switch. I plan on instsalling a switch so I can turn them on without the backup lights if I want as well as having them come on when in reverse.