backwoods, the high beam relay wire is for the "fog" lights to turn off when the factory high beams turn on. It's called DOT (Department Of Transportation) high beam interruption. I'm not criticizing any one's wiring methods, I was taught Ford, Dodge and Chevy electrical wiring safety codes at the chassis up fitter. I was head electrician on the truck line for 5 years, better safe than sorry. Using those black plastic illuminated switches rated at 10 amps without a relay: An average set of "fog" lights draw 15 amps, the lights are drawing 50% more current than those switches are rated for. I've seen many melted switches before when repairing other people's wiring. Get a relay harness or a switch rated at 25 amps. If not using a relay, Walmart sells heavy duty switches for $4.48, they are the metal housing switches. I wouldn't recommend straight wiring any added on circuits. Always use a fuse or circuit breaker (ShortStop) within 8 inches of constant battery power. Great fire story Vano. If you don't want DOT interruption for high beam delete the second relay setup, #87 output goes to "fog" lights. At least this method: battery, 20 amp fuse, 25 amp switch, lights. A Ford dealership in the late 1990's, eastern TN bought our fog light spoiler, set of lights and relay wiring harness with led switch, they wanted to charge the customer instead of paying us to wire it up on a F350 dually. They called us three times trying to get the fog lights to work, we fully explained the connections and even faxed them a diagram. The customer finally brought us the truck, saying that the Ford dealership claims there is something wrong with the wiring harness. I found out why it wasn't working, they had tried to ground the fog light wires to fiberglass instead of connecting the light's black wires to the black wires in the harness next to the red wires. They used the red power wires but not the black ground wires?
i posted a diagram in here on how you should wire it all up, w/ a relay, inline fuse, toggle switch, the whole kit and kaboodle. i think it might have gotten lost before you saw it. Scroll back (maybe pg 2?) That way I showed is exactly how Roush PSD is describing.
The best wiring I've ever seen: They ran directly off the battery some 110volt romex home wiring, 14 awg soild copper, thru the firewall to a home 110volt light switch, then back thru the firewall to the lights. They didn't understand why it worked for a while then stopped.
Relay one (bottom): The toggle switch energizes the coil in the relay, contact 85 (ground) and contact 86 (switched power) A relay is an electromagnetic switch. Energizing the coil, the relay switches from normally closed, contacts 30 and 87a were connected at rest. Power switches from contact 30 to 87 thereby power is sent to the lights from contact 30. Relay two (top): Contact 87a is Normally Closed, power from contact 30 goes out to 87a with the coil at rest. When high beam turns on, the relay's coil connections 86 (high beam) and 85 (ground) cause the relay contacts to switch, thereby stopping the flow of electrical current at contact 87a to the fog lights because contact 30 and 87 are now connected. A relay can use either ground triggering, or battery + to activate the coil within the relay. Negative trigger, the switch is a ground interruptor and relay coil contact 85 is constant power. Relays are useful as polarity switchers also. A negative signal from an alarm system can be converted into a positve signal to operate lights or an accessory.
Dang Joe, are you an electrician? Those are some sweet diagrams. He doesn't want them on with the high-beams though (some legal issue). Just a switch in the cab. Backwoods - Look at my last post on page 2
Ya sorry Joe,you are way over my head,lol.I said simple instructions.lol.I only wish i knew half of what you said when it comes to electrical there man.
