my friend just gave me some KC highlights and iw as going ot use them as reverse lights instead of my pilot ones, i want to be able to have them come on w/reverse and also have a switch inside to turn them on when i want them anytime, is there a relay i can get for that?? and id prob have to use a 3-way toggle switch also.

here are the lights can some one tell meif they are good if u have also.

http://truckperformance.com/products...number_KCH775/

thanx

 

You could use two SPST or two SPDT relays and power the coil on one relay from the new switch and the coil on the other from the BK/PK reverse light wire.

OR

You could diode isolate the two inputs above and use them to power the coil of a single relay.

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In either case, the pinout for each relay would be:
85: positive trigger(s) from switch and/or reverse lights
86: chassis ground
30: fused battery voltage
87: output to KC's

The current rating of the relay(s) should be high enough to handle the 2 KC's - common 30A Bosch-pattern automotive relay(s) should be more than adequate.

The wire switched through pin 30 and 87 must be of adequate gauge for the amp draw of the KC's. The fuse from B+ must be correctly sized to protect that wire.

 

There are lots of ways to do what you are looking for. If these are 55 watt or more lights, you'll definately need to run a new power wire back to them. The stock reverse light circuit will not support that.

Run 12 gauge from the battery to the back of the truck. Connect this to pin #30 on the relay. This is the new main power. Make sure you have an inline fuse within a foot of the battery.

Run a small wire, 18 guage is more than enough, from the fuse box to a switch on the dash. Make sure you have an inline fuse (2 amp) withing a foot of the fuse box. I like using a circuit that shuts off with the ignition so the lights can't be left on. You can really pick anything since this isn't adding and significant load.

Continue the 18 gauge wire from the switch back to the relay. Get a diode from radio shack. Nothing fancy, almost any of them will work. The diode will have a line on end of it. This line goes on the side toawards the relay. Connect this wire to pin #85 on the relay. This is your new manual control circuit. The diode is a one-way valve that prevents backfeeding from your reverse lights circuit.

Splice into the existing reverse light's postive wire. You'll need to go to radio shack and get a diode. Nothing fancy, pretty much any one they have will work. Put this inline just like you would with a fuse. The diode will have a line around one end of it. Put this line towards the relay. Connect this wire to pin #85 of the relay as well. This is what will trigger the relay when you put the truck in reverse. The diode is a one-way valve that will prevent back feeding again.

Ground pin #86 of the relay with 18 gauge wire.

Use your 12 gauge wire to go to each light from Pin 87 of the relay.

Now the new lights will come on when you put the truck in reverse or when you flip the switch. If you don't want to do the switch part, you can eliminate all the diodes and use just the splice from the reverse lights to pin #85.

 

Here's the two ways that were explained for reference. Not everything is labeled so you will have to figure some of it out on your own.

If something is wrong in the diagram please let me know.

 

ok i got all the wiring down so does the normal auto store carry these relays i thinki just going to use when reverse comes on, so the reverse circuit attaches to the 85, 86 attaches to ground, and the power wire go to 30, and whats the # that the lights go on to??

thanx for the help guys!

 

87

 

ok thanx!! do they sell them at all places or do i have to order??

o ya duh i dint read the botom part of ur first message bob lol just noticed i prob sounded like and idiot befor lol.

thanx

 

You can get the relay at any auto parts store or Radio Shack. Expect to pay $5~10 in a store, $2~4 online. I buy genuine Ford heater blower relays for $7 from the dealer because they seem to last forever.





Relay sockets are not always as easy to find as relays but they make wiring simple and reliable.



As an alternative, you can also use individual spade terminals on the relay.

 

ok thanx bob that helps seeing what it look slike so i know what i talking about to them thanx man

Nick

 

honestly you dont need the diodes, just connect the line from the switch and the line from the reverse lights power to the same pin on the relay. when either one gets power it will turn on the relay. they are both 12v positive circuits, so connecting them will cause no ill effects, its not like one is positive and one negative where it would be grounding out.

 

Actually, yes you do. I wouldn't suggest the poor guy go through all those steps if it wasn't neccessary. Backfeeding power from one protected circuit to another protected circuit is bad and the fact that is just all +12 has no bearing on this.

 

you don't backfeed power into protected circuits, with one switch off and the other switch on power flows from the switch that is on, through the relay and to ground, there is nowhere for it to flow in the switch that is off because all that is there is a piece of wire with nowhere to go. with one switch turned off it is an open circuit and power tends to not flow through open circuits. hook up a wire to one side of a light bulb and connect the other end of the wire to power, what happens? nothing because there is nowhere for it to flow. it would be the same thing as connecting the signal wire from the reverse switch on teh transmission to the relay so it will turn on when put in reverse, and running a wire from a switch to the reverse switch jumping the reverse switch manually. all you are doing basically is running the switches parallel to eachother. you dont need to overcomplicate simple wireing. we're not dealing with complicated sensitive electrical components here, its solid state 12V wireing with no components.