I am planning to recess two of these lights into my rear bumper on an ON-OFF-AUTO switch as extra reverse lights. Current Draw: 0.130 Amp (130ma) @ 13.5 VDC.

M4 series Marker Lamp

I would like to pull power from the reverse lights or switch somewhere under the hood. (Need to find the fuse or wire) and can I just pull a constant power from somewhere in the fuse box? I have been looking over Matt's wiring guide but don't think that I really need a relay and the full current from the battery to run these.

 

since the reverse lights run through the trans range sensor, i would not risk it and run a relay

 

Where would you take the power from for the auto function?

 

Its an easy circuit to wire, what you need to do is use a 5 pin relay, connect the lights to the 30 pin, connect a switch to the normal closed pin and use the stock reverse lights to close the normally open circuit. then the lights will activate when you flip the switch or automatically when you shift to reverse.

 

Do I need one if I have a manual

 

yes

 

do it right and use a relay

 

Where would be the best place to pull the power from the reverse lights? The fuse for the reverse lights are in the fuse panel beside the passengers feet.

 

Run power from the under hood distribution block, then either use a switch, and or the reverse lights to fire the relay. How you wire the trigger depends on weather you want the lights on with the reverse lights, or with the switch or both.

 

On/auto/off as stated above

 

Since we're only talking about 3.5 watts TOTAL for both of the added LED lamps compared to 50~55W for the factory reverse lamps, it's hard to understand why a relay would be needed to handle the additional power. I don't think that even Ford cuts it that close. LOL

A relay could be used in the selector circuitry but even that isn't absolutely necessary. It seems like it could be done using a single pole, double throw switch with center off plus a little wire.

I could be wrong but my first instinct is that these are not going to be much better than the stockers alone. Marker lights, yes; reverse lights, maybe not.

 

I agree with Bob on the relay (who wouldn’t), not really needed, but use an “On/On” type of double throw sw….
Check the sw for the pin out based on Lever Location and use the Sw up as Manually on and the Sw Down as auto.
this way the lights are either on or waiting for reverse.

Cntr Pin = to Load or to the lights.
Top Pin = attach the OEM Backup light wire from the Trans with a fuse added.
Bottom Pin = Attach a fused power wire from the battery.

If, after wiring, the sw is reversed, just flip it over.
If the sw uses solder type connections, test everything before soldering and after verifying clean the joints with alcohol and use a good quality heat shrink over the connections.
Do the same with Crimp Lug but you can do it as soon as you crimp them.
Run a ground wire from the lights back to the frame, making sure you get to bare metal and use a good quality electrical paste on the connection.

 

If I understand correctly, the OP also specified an "always off" option for the aux lights. That's why I suggested a double throw switch with center off - that would give an on/off/on arrangement.

 

Yup I see what you are saying I missed it… but my way is almost right.
I would think he would want them to operate with the backup lights when the switch is on the down position (if wired correctly) or auto position the lights will only come on when the OEM sw is in reverse.
I would think if you got um use um.

My bad sorry about the confusion on my part.

 

Your way is what I had in mind. Wire the center switch terminal to the hot of the lamps, one of the outer terminals to the fused reverse lamp circuit and the other outer lug to a fused hot in Run/Acc. Using a center off SPDT, that should give:

• On with key in RUN/ACC at one switch extreme
• On only when in reverse with key in RUN at the other exteme
• Center off.

This would eliminate the possibility of accidentally leaving the aux lights on when the key is removed.

 

rwenzing, That is what I'm going for. I already have a On/Off/Auto toggle switch installed in the a-pillar with nothing connected to it. The two others are for my PIAA's when I figure out how I want to mount them and my roof lights. I was just going to keep it to save not having to buy another one and I always like to shut everything off when the truck is off. Idk, personal preference.

If you look at the initial post of this thread, what size fuse should I go with.

Maybe this isn't a good idea but I think it will be different.

This is were I go the inspiration...'http://www.youtube.com/watch?v=sMdNc-t4dew'

 

0.130 amp x 2 lights = 0.26 or just over ¼ amp, not much current required for LEDs.
Running a one amp fuse will cover the lights by 2 and should cover any surge at turn on.
Always fuse for the lowest amperage draw component, i.e. the lights

Interesting stuff, good viewing, thks

 

Can I use a fuse tap to pull power from the reverse fuse for the auto function? But as Scrambler stated I only need a 1 amp fuse to handle the current for these lights.

The fuse taps I have seen hold two ATC fuses. Would one be for the original function (reverse) and then the other directs power to your added circuit only when power flows through the original? I want to do this as cleanly as possible. I hate hack jobs and messy wiring even if it is going to get covered up by the cover panel.

 

No because the fuse is upsteam of the switch. If you tapped in at the fuse that serves the reverse lights, the wire would be hot whenever the ignition switch is on, not just in reverse.