relay control led lights 2way?

i know what i am looking for can be answered because my old ex co worker did this similar set up in his car for some interior lighting.

here is what i am trying to do:

i just added rear led work lights on my 00 f250 truck. right now they are wired to come on with the reverse lights. i would also like to be able to control them via a toggle switch which i will wire to constant battery power. (i sometimes do work at night and want to be able to turn them on with the truck off).

i remember my coworker did this with interior led lighting that he made his underdash lights come on with the doors when they were opened, and they also came on when the parking lights were turned on. i know that all he did was use 2 relays but i don't know what this method is called so i don't know what type of diagram to search for.

please help. would like to do this wiring this weekend

This:-
One 5 pin automotive relay.
Take feed from reversing light to 87a
Feed from 30 to work lights.
Battery via fuse and switch to 86 and 87
85 to ground.
That's it.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

not sure i understand when you say battery via fuse and switch to 86 & 87. wouldn't feeding 2 contacts to the same terminals cause a backfeed somewhere?

No

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Howie doesn't take time to explain why things will work the way he suggests.

#30 is the output to the work lights

87a is the at-rest input from the reverse lights.

Note that 85 and 86 are the coil in the relay. When the coil is energized, #30 is connected to #87, and Disconnected from #87a. 85 grounds the other side of the coil.

So when your Manual Switch is ON, it puts B+ to both the 87 for the power to the lights, AND to the relay coil #86 to switch the source of power for the work lights. There can be no backfeed, because the reverse lights only go to the work lights when the manual switch is OFF.

It's not that hard to explain things, Howie. If everyone was as "good" as you are, your input wouldn't be needed at all. It's called "teaching".. You had to learn this stuff from somewhere. The reward from teaching is that the teacher gets to refresh his understanding of the subject when teaching it to others. Teaching helps us old-farts keep our minds sharp.

I do apologise it was 11:00 pm when I replied, I had to be out at 6:00am the next morning I did a diagram for our OP and couldn't find it.
To be honest it's a very simple circuit, often used for lighting circuits where various regulations discourage say front fogs on with Hi-beams, I'll try and find it.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

Meanwhile here's an even simpler way of doing it:-
B2F_2_source_relay.bmp

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

davep. wrote:

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Howie doesn't take time to explain why things will work the way he suggests.

#30 is the output to the work lights

87a is the at-rest input from the reverse lights.

Note that 85 and 86 are the coil in the relay. When the coil is energized, #30 is connected to #87, and Disconnected from #87a. 85 grounds the other side of the coil.

So when your Manual Switch is ON, it puts B+ to both the 87 for the power to the lights, AND to the relay coil #86 to switch the source of power for the work lights. There can be no backfeed, because the reverse lights only go to the work lights when the manual switch is OFF.

It's not that hard to explain things, Howie. If everyone was as "good" as you are, your input wouldn't be needed at all. It's called "teaching".. You had to learn this stuff from somewhere. The reward from teaching is that the teacher gets to refresh his understanding of the subject when teaching it to others. Teaching helps us old-farts keep our minds sharp.

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I'm a little confused on how you explained this when you say "when your manual switch is on, it puts 12v to the 87 and to #86 to switch the source of power for the work lights".

The factory reverse lights on the truck need to work as they are normally function when in reversed, as well as power the work lights.

I want to hook up the reverse lights to a constant battery source (which I will fuse and run wire) to a switch that will also be powered whether the truck is on or off so I can turn the lights on at anytime.

I'm sorry if i'm making this harder than it may seem.

Is there a technical term of what I'm asking? I am curious if others have done this with photos so I can see it exactly. I don't mind doing some testing on my work bench prior to installing to make sure it works.

I'm OCD when it comes to vehicle wiring and hate cutting into my clean wiring if something was done wrong or wired wrong.

Thanks for all the help so far though!

I reviewed your opening post. You have the work lights wired TO the reverse lights. So when the transmission is in Reverse, the reverse lights come on. If this is OK (that the reverse lights come on with the work lights) in Manual On mode, here is a suggestion.

The reverse light wire in an 00 F250 is blk/pink. The switch is on the driver side of the transmission. (Automatic). The easiest place to intercept this wire is at this switch. Find it, TEST IT, then cut it. Extend the wires to your relay.

87a  = the blk/pnk on the switch-side.

30 = the blk/pnk on the vehicle side.

(at this point, with no other wires on the relay, the reverse and work lights will function just the way they do now, because there is continuity from 87a to 30).

Now Connect:

85 = ground. (this is for the coil in the relay)

86 = to the Manual On switch B+.

(Now turn your switch off and on. You will hear the relay "click" but nothing will happen. Put the trans in Reverse with the key on, (reverse lights are on) and turn the manual switch off and on. The reverse lights will go off when the switch is on because  #30 (the lights) are being connected to #87, but there is no power on #87).

Now connect::

87 = B+ from the Manual On switch.

(Now with Manual Switch ON, there is continuity from 87 (B+) to the reverse lights (30) and the lights are ON). (If the transmission is also in Reverse, and the key is in RUN, the reverse lights will be on in either switch position. Turn off the key, and they will only come on in Manual ON.

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Print this post. Take it to the bench and follow the steps. Hopefully it helps you understand how relays work.

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Sorry. I'm unable to draw and then post diagrams. I don't have the necessary equipment or programs to do it. All I can do is post circuit descriptions, relay numbers, and wire colors.

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Inside Joke: Cheers, Howie!

Oh very funny! On a serious note, FUSE the common wire to 87 and 86 BEFORE the switch. This wire is a 12V+ constant.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

howie ll wrote:

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Oh very funny! On a serious note, FUSE the common wire to 87 and 86 BEFORE the switch. This wire is a 12V+ constant.

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Good point on the fuse. Use the lt blu/pnk wire at the transmission switch as the power source for the Manual switch. Then the reverse lights, work lights, relay, and all associated wiring is on the same fuse. #28, 10A, in the dashboard fuse center.

Is that constant or ignition Dave? Personally I'd have fed the switch from a constant.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

RATS!

Howie caught my mistake, He's right, lt blu/pnk is only hot in RUN. You need a constant.

Ha ha!

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.

i got it to work and used the original relay diagram that you gave me howie

thanks!!! A+++ works 100% just like i want it to