Wiring Uncertainty

[Norris Marshak]

Guys, I hope you can give me some guidance because I had the fellow who does my audio/stereo wire the Hella lights on the Wilderness rack I picked up. I don't think things are as they should be; I have an appointment to have him check his work.

This is the exact situation. Because I didn't want to cut a whole in the roof of my 60, I had him use a trailer hitch wiring set up, so I could complete the harness through the driver's window and have the lights connected only when I would choose to use them. So picture a harness/loom for all the rack lights coming through the window to be attached to the other harness section affixed to the bottom of the dash near the hood release. The various lights, 2 fronts, right side, left side, and rear pair are switched to what I thought was a nifty electronic dash push pad and under dash unit that accomodates four light sets. I picked this unit up at Auto Zone. It has an electrical band that goes from the under dash unit to the push pad. The installer said the unit has internal relays, and therefore did not install individual relays. However, when I had the full headress activated tonight and revved the engine, I smelled electrical burn and saw smoke coming from near the control module. Needless to say, I killed the power to the lights. I have a Wednesday appointment. If you guys can give me your ideas on what's wrong, I would sincerely appreciate your input. I want to have frame of reference for what he tells me.

I'm guessing maybe that the concept of the harness/loom may be good but the inside section of the harness may not have heavy enough wire to handle the draw. The ouside section of wire has, except for the the first foot of harness 12 or 14 wire from the rack junction box.

Thanks so much for your patience with this junior who is an electrical newbie.

 

[Tinker]

Watts = Volts X Amps. If you have 6 100W lights, they're pulling 50A at 12V. There are tables that show how big the wire has to be for X amps over Y distance (Direct Current).

What you performed is known in professional electrical/electronic circles as the "smoke test". It failed.

Your Vato Zone setup is too puny. And your stereo guru doesn't seem to know his As, Vs, & Ws.

 

[Bret]

I would make sure that there are relays that can support the current demand of your lights. The other question I would ask is where does the power for those lights come from anyway?

If I was to wire them I would have a heavy gauge wire (depending on current demand) that is fused at your battery feed a relay to control the light(s). Bear in mind that the "normal" 12V relay's are rated for 30A so each relay may only support 2 lights. Another option would be to get a "heavy duty" relay that will support all the lights. Bosch makes a pretty good relay that is good past 75A (look up the e-fan posts for more info). Then you can have a switch in the cab wired to control the relay(s) under the hood. The connectors you are using will also have to support the load that you put on them. The 4 wire trailer harness does not come to mind...

Is there anywhere in the back that you may be able to run your wires up to the rack? Seems like trying to use a connector would pose other problems like corrosion? Maybe time for a snorkel??? (J/K)

 

[Norris Marshak]

Guys,please keep the advice and suggestions coming. Tinker and Bret, both of you have given me reason to not use these lights as they are currently wired. What you both have said means I probably should have at least #6 wire(50 amps) with a fusible link or circuit breaker coming from the battery to a junction point (e.g. Bosch relay} where the #6 will feed four #12 wires, each going to four switches each capable of a 20 amp load. In creating this configuration, I've tried to factor in the total draw of the lights(50 amps) and the portion of this burden each switch will have to carry. 200 watts requires wiring and switch capable of handling 200 divided by 12 volts.

It seems, therefore, that # 12 has to find its way back to each of the lights. As far as my accessibility issues, I'll think about those when I'm certain I have the wiring correct.

I don't think this was done correctly by my stereo guy. I suspect the distribution system is good but the capacity of the parts and total wiring inadequate.

Please give me some additional feedback. Right now, I'm trying to get the egg off my face. Feeling stupid and embarrassed.

 

[Tinker]

Norris -
Unless you supervised the installation, the egg is on your guy's face. Stereo amps & speakers work the same way - components must be properly sized for the loads.

You could still use the switch panel to control heavier relays.

Post up some pix! It looks like a good idea, just a bad first stab at wiring.

 

[Bret]

It it were mine... I would run the heavy gauge wire to a 4 place fuse holder (to power the fuses) then each fuse would power the relay "common". Then from each relay output I would run the power wire to the lights you wanted, being sure to gauge the wire based on number of lights powered. To wire the switch(s) you could pull power from anywhere under the dash to your switch and go from your switch to the "control" on the relay. The relay could be grounded next to its mounting point to make things easier. The control wire would not have to be "heavy duty" because it draws very low current. You may be able to control the relays with a version of the switch you got from the auto-droid store.

Remember that you will also need to have the lights grounded. If you ground the lights on your roof rack the roof rack will also have to be grounded in a way that will support the current draw too.

You may be able to get away with lighter gauge stuff but the more voltage you provide the lights the brighter they will be. This is why some folks use relays to feed their headlights. Many times the lights don't get "full" voltage so they aren't as bright as they can be. I am also pretty sure the rating of the light is based off around 13.8V, if the light only gets 11V because of the length of wire carrying the power the output will be lower. this may not be a concern for your application (at least not for the sides and rear)

Go down approx 1/4 of the way and you will see a graph showing this.
Toyota 4Runner and Pickup: Brighter Headlights

Not trying to make it impossible to run your lights, just hoping that you can make informed decision on where you want to end up. If you "overbuild" it a little upon installation you should have a end product that meets your wants.

 

[Tinker]

Brett & Norris -
You might want to divulge your locations in your sig (unless, of course, you're in the witness protection program). You never know how many Cruiser neighbors you have.

 

[Norris Marshak]

Long Island, New York, but keep it under wraps!

 

[Bret]

Melbourne, FL unless I owe you money, then I live next door to Norris