7way- black is 12volt (power), brown, running lights, yellow is left turn signal and stop light, green is right turn signal and stop light, white is ground, blue is brakes, and orange is aux power (can be back up lights, if trailer equipped w/ them). 6way is the same, minus orange wire. I have run into some variations to the above color codes (brown, yellow and green only-sometimes these 3 are different than stated, but only mixed as that group, as to what they control- example would be green is running lights, brown and yellow are turn signal and stop lights, the others should be as stated), if you have any trouble with things not working properly, it may be due to these variations, although the above are pretty standard. If you have an ohm meter you can check as you go (check for power at black wire- should be constant 12v, turn on turn signal and check for power-it will fluctuate from approx. 12 volts to 0 volts as the signal power pulses in the wire) hit the brakes, blue wire should show power, etc. Let me know if you need more help as you go.
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Trailer tow connector.
Brown wire with white tracer is voltage for park lamps, comes from trailer park lamp relay.
The yellow wire is voltage for left turn, comes from left turn trailer relay.
The dark green wire is voltage for right turn, comes from trailer right turn relay.
The white wire is ground, check voltage and ground. Use a test light. I don't know what testing you have done?
There are several diagrams for this system.
bbbind.com has free diagrams.
The brown wire is voltage, the black wire is ground. Use a test light to check both. The front park lamps, side marker lamps, rear tail lamps, license plate lamp, all go hot when you turn on head lamp switch. as far as voltage, if some of these lamps work and others don't then check for possible wiring circuit problem. Do check the ground, also.
The ABS controller has nothing to do with the back lights. Please anyone reading this post, do not mess with anything concerning ABS systems. An ABS light on will not effect conventional brake function. It can only be serviced by a trained tech. Also very expensive. Your original problem is most likely at the harness connector, located in the frame between the rear axel and bumper. If the truck has been used for pulling and launching a boat, this is where a trailer light harness is tapped into for trailer lights. Backing a boat into the water compromises this connector. (corrosion will not let the truck lights work) The connector is usually on left side frame rail) Conductive grease after cleaning
They are turned on by the BCM !
Park, Tail, Marker and License Lamps
The park, tail, license, and marker lamps are turned ON when the headlamp switch is placed in either the HEAD or PARK lamp positions, or anytime the automatic light control (ALC) turns the headlamps ON. When the headlamp switch is placed in the park lamp or headlamp positions, ground from G202 is applied through the signal circuit to the BCM indicating the park lamp request. In response to this signal, the BCM applies ground through the park lamp relay control circuit energizing the PARK LP PCB Relay. With the relay energized, battery voltage is applied through the switch side of the relay, both park lamp fuses, and the supply voltage circuits illuminating the park, tail marker, and license lamps. Ground for the left front park and marker lamps is provided at G101 and the right front park and marker lamps at G100. Ground for all rear lamps is provided at G302.
Turn Signal Lamps
The LT T/SIG and RT T/SIG fuses located in the underhood fuse block supplies battery positive voltage to the body control module (BCM) for turn signal and hazard lamp operation. When the turn signal switch is place in either the LEFT or RIGHT position, ground from G202 is applied through the turn signal switch signal circuit to the BCM indicating the turn signal request. In response to this signal, the BCM applies a pulsating voltage to the front and rear turn signal lamps supply voltage circuits cycling the lamps ON and OFF. The BCM also sends a message via GMLAN to the instrument panel cluster (IPC) to cycle the turn signal indicator ON and OFF depending on the position of the turn signal switch.
Ground for the turn signal lamps is supplied as follows:
G101 provides ground for the left front turn signal lamp
G100 provides ground for the right front turn signal lamp
G302 provides ground for the left and right rear turn signal lamps
The wiring diagrams on 2000 and newer models are not easy to read sometimes, but it shows a 30amp park lamp fuse and a park lamp relay. The relay is controlled by the PCM. There is also a 10amp Int - Park fuse. I think the small fuse is inside the passenger compartment and the large fuse is in the engine compartment box. You may have to get a shop manual to get the diagrams to be able to check each circuit.
Do you know what a wiring diagram is ? How to use a DVOM - digital volt ohm meter ? Free wiring diagrams here http://www.bbbind.com/free_tsb.html Enter vehicle info. year make ,model and engine size. Under system click on lighting ,then under subsystem click on turn signals . Click the search button then the blue links .Check power an ground circuits ! This is how we diagnose electrical faults , not just replacing parts .
Voltage is applied through the TURN fuse and the turn/hazard flasher when the ignition switch is in the following positions:
• BULB TEST
The voltage travels to the contact in the hazard switch. The hazard switch is located in the turn/hazard-headlamp switch assembly. This contact is normally closed.
When the left turn signal is turned on, voltage is applied to the following components.
• The left turn indicator
• The left front park/turn lamp circuit 14
• The left rear turn lamp circuit 18
The turn lamps turn on immediately. The current flow heats up the timing element. The timing element is located in the turn/hazard flasher. The timing element repeatedly opens and closes the circuit. This action causes the turn lamps to begin flashing.
The voltage that is applied to the left front park/turn lamp is also applied to the left front marker lamp. If the headlamp switch is in the OFF position, the left front marker lamp will find a path to ground through one of the following lamps. The following lamps provide low resistance paths to ground:
• The right front marker lamp
• The right turn indicator
• The right front park/turn lamps
• The left front park/turn lamps
The left front marker lamp flashes with the turn lamps. The voltage drop across the marker lamp is much higher than the voltage drop across the other lamps. The lamps that are used for the ground path will not flash.
When the headlamp switch is in either the PARK or HEAD positions, voltage is applied through the following components:
• The EXT LP fuse
• The marker lamps
• The park lamps
When the left turn signal is turned on, the left marker lamp will have voltage at both connections. The left marker lamp does not light. When the turn/hazard flasher stops the voltage to the turn lamps, the marker lamp is grounded through the turn lamp. The marker lamp does not go on. The left front marker lamp flashes in the following manner:
• The left front marker lamp flashes on when the turn filament of the left front park/turn lamp goes off.
• The left front marker lamp flashes off when the turn filament of the left front park/turn lamp goes on.
Voltage is applied to the right lamps in the same manner, when the right turn signal is turned on.
Voltage is applied at all times through the following components to the normally open contact of the hazard switch in the turn/hazard-headlamp switch assembly:
• The STOP HAZ fuse
• The turn/hazard flasher
When the hazard switch is turned on, voltage is applied to the following components:
• The front turn lamps
• The rear turn lamps
The following lamps flash on and off:
• All of the turn lamps
• Both of the turn indicators
The front marker lamps flash with the hazard lamps on, just as the front marker lamps flash when the turn lamps are on. If the headlamp switch is in the OFF position, the front marker lamps flash on when the hazard lamps are on. The front marker lights will flash on when the hazard lamps are on if the headlamp switch is in one of the following positions:
When the hazard lamps are on, the following conditions apply:
• The turn circuit is always open.
• The turn/hazard flasher controls the lamp.
Voltage is applied through the EXT LP fuse, to the headlamp switch at all times. Voltage is applied to the park lamps and the marker lamps when the headlamp switch is in the following positions:
The front marker lamps are grounded through the turn filament of the respective front park/turn lamp. The front marker lamps light as a result.
Voltage is applied through the STOP HAZ fuse to the brake switch at all times. When the brake pedal is depressed, the brake switch closes. This action applies voltage through the turn/hazard-headlamp switch assembly to the following lamps:
• The high mounted stop lamp assembly
• The left tail/stop-turn lamps
• The right tail/stop-turn lamps
You can find free wiring diagrams here http://www.bbbind.com/free_tsb.html Enter vehicle info. Year , make , model an engine size . Under system click on brakes .under subsystem brake control will show on it's own . Click the search button .