7 pin connector trailer back up light no voltage

Here ya go.

Lighting control module ? ?????? Hazard / flasher module ! Now ( there''s not even an electrical signal where the fuse plugs into the interior fuse panel.) What FUSE ??????

Stop Lamps
The STOP LP 25 A fuse in the underhood fuse block supplies battery positive voltage to the normally open stop lamp switch. When the driver presses the brake pedal, the switch contacts close and battery positive voltage is supplied to both the STOP 15 A fuse and the CHMSL 10 A fuse in the I/P fuse block, and to the turn signal/hazard module. The turn signal/hazard module then supplies voltage to both of the trailer rear turn/stop lamp supply voltage circuits. The voltage from the CHMSL 10 A fuse is to the center high mounted stop lamp (CHMSL) and the trailer jumper harness. The voltage from the STOP 15 A fuse is to the stop lamps, throttle actuator control (TAC) module, and the cruise control.
Backup Lamps
The backup lamp request signal is sent from the powertrain control module (PCM) to the body control module (BCM) on the Class 2 message system. This signal is based on the park neutral position (PNP) switch signal. The BCM supplies voltage on the backup lamp supply voltage circuit to the backup lamps and to the automatic day/night mirror. Voltage for the courtesy lamp supply voltage circuit and backup lamp supply voltage circuit is from the TBC B fuse in the instrument panel fuse block directly through the BCM to these circuits. A short to ground on either of these circuits will open the fuse. The backup lamps are grounded at G401.
For trailer wiring, a separate backup lamp circuit is connected through the underhood fuse block from the TRLR B/U 10 A fuse to the trailer wiring harness.
Turn Signal/Hazard Lamps
The IGN E 10 A fuse in the underhood fuse block supplies battery positive voltage to the turn signal/hazard switch assembly. The FLASH 25 A fuse in the I/P fuse block supplies battery positive voltage to the turn signal/flasher module and ground is supplied at G200. When the turn signal switch is placed in either the left or right position, a voltage signal is completed from the turn signal switch to the turn sign/flasher module. When the hazard flasher switch is activated, a ground signal is completed from the turn signal/hazard switch to the turn sign/flasher module. The turn sign/flasher module then sends an on-off voltage signal through the LT TRLR, RT TRLR, LT TURN or RT TURN 10 A fuses in the I/P fuse block to the appropriate turn signal or to all 4 fuses for hazard operation. The instrument panel cluster (IPC) indicators receive voltage from the LT TURN and RT TURN fuses as well as the DDM/PDM for the mirror turn signals. The DDM/PDM has no function or control of the mirror turn signals other that a pass through connection for the circuits. The audio chime is also activated when the turn signals are on. When the hazard switch is pressed, all turn signal lamps will flash including both IPC turn indicators. The front turn signals are grounded at G100. The rear turn signals are grounded at G401. The Mirror turn signals are grounded by the DDM/PDM.

Do you know how to do automotive electrical circuit testing with a test light or volt meter ? How to read an use a wiring diagram to pin point testing points . ( connectors , fuse locations etc... ) How to use a power flow chart ? Here is a site for just such info .

http://www.bbbind.com/free_tsb.html Enter vehicle info . year , make , model an engine size . System click lighting , subsystem exterior lighting . Second diagram shows trailer wiring .
Electric Testing Techniques You Need to Know

Mastering Voltage Drop Testing with Pete Meier and Jerry Truglia

CHEVROLET 2007 SILVERADO TRAILER LIGHT TROUBLESHOOTING

Hi Donald,
It sounds like a wiring issue. Double the wiring to your connector on the vehicle. Also check the wiring on the trailer connector. I have seen many trailer that are wired to ground through the ******, this of course will cause an intermittent ground and flickering lights. you only need four (4) wires... One for a ground, One for running lights, and Two wires for brake and turn - one wire for the left and one wire for the right. You can also find the proper pin wiring for vehicle and trailer on the internet. Cheers. I hope this helps. John

I'm not sure if it can be. Lots of these newer connectors are sold as , you know, only complete and you splice it in. Is it bad on the switch side or the body harness side of the connector? Heck, if it's just to the back-up bulbs, you could connect the two wires together outside of the connector, and bypass the connector problem on that one wire. That would be the easiest fix, as long as the other pin connections are good
Now on the older removeable spade type connectors, you slip a fine wire or needle along the top of the metal pin to push down a little tang, and then the wire and pin will pull out from back of the plastic connector.
Well, good luck, Bill.

Hi, this may true if you connected the trailer brake to the connector on the factory wiring harness. There are several fuses that are needed for trailer towing. In the box by the battery, fuses 13, 25, 27, 53, and 54 are needed. You will need a relay in relay slot 19 for the trailer running lights, a relay in relay slot 20 to charge the trailer emergency battery; and, if your trailer has backup lights (6 or 7 wire connector), you will also need a relay in the relay slot 15. If you did not use the factory connector for your trailer brake controller, check to make sure you have connected the controller to an appropriate power source in the truck. Please let me know if you have questions, and thanks for using FixYa.

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Trailer Wiring Diagrams 4 Way Systems

4 way flat molded connectors allow basic hookup for three lighting functions; right turn signal / stop light (green), left turn signal / stop light (yellow), taillight / license / side marker (brown) and a ground (white).

4 way tow vehicle side.
4 way trailer side.
5 Way Systems

Same as 4 way system listed above but adds a extra blue wire for brake signal or auxiliary power. Used on pop up camper trailers or utility / boat trailers.
5 way tow vehicle side.
5 way trailer side.
6 Way System, Rectangle Plug 3/4 inch by 1 inch 6 way rectangle connectors right turn signal (green), left turn signal (yellow), taillight (brown), ground (white). The red and blue wire can be used for brake control or auxiliary. Use on a small motorcycle trailer, snowmobile trailer or utility trailer. Can also be used as custom wiring on trailers with 3 light/wire systems. See "Tow Vehicle Taillight Wiring" below.
6 way tow vehicle side.
6 way trailer side.
6 Way Systems, Round Plug

Round 1 1/4" diameter metal connector allows 1 or 2 additional wiring and lighting functions such as back up lights, auxiliary 12v power or electric brakes. Note: The black (sometimes red) 12v and blue electric brakes wire may need to be reversed to suit the trailer. Check with a test light or VOM. Uses: horse trailer, travel trailers, landscaping trailer, car trailer, etc.

6 way tow vehicle side.
6 way trailer side.
7 Way Systems

Round 2" diameter connector allows additional pin for auxiliary 12 volt power or backup lights. Uses: heavy duty landscaping trailer, car trailer, boat trailers, horse trailer, travel trailer, construction trailer, etc. Check with a test light or VOM.

7 way RV flat blade tow vehicle side.
7 way RV flat blade trailer side.

Did you check for voltage at backup lamp fuse, use a test light. The actual diagram I copied was larger than this and easier to read. This must be a site issue, common to fixya. You could even use a long piece of jumper wire from battery voltage to light green trailer wire, to see if lamp will light. It would'nt hurt to use inline fuse, for testing. If lamp still won't work, maybe problem with trailer wiring. You could even use jumper wire to bypass the connector itself, same color wire?

Check and read Trailer Wiring Connectors Various connectors are available from four to seven pins that allow for the transfer of power for the lighting as well as auxiliary functions such as an electric trailer brake controller, backup lights, or a 12V power supply for a winch or interior trailer lights. Choose a connector that has the required number of pins for the functions required for your trailer. If the connector is under the vehicle, you will want to use a mounting bracket to attach it to the vehicle. This will help prevent damage that may occur if the connector is left dangling.



Good luck (remember rated this help).

I believe the box also is a safety feature in case of a wiring problem from some event, like an accident.
You need a converter to convert the turn signals and brake lights to run off the one bulb on the trailer. A flat 4 pole connector is the usual connection. A 4 to 5 pole converter may also be needed to add the backup light power to disengage the surge brakes while backing up If your trailer has that option. 4 to 5 is not really necessary but it eliminates having to get out and move the connector or insert the brake bypass key.

You'll need to disconnect the wires from either the truck connector or the trailer connector...
I highly suggest purchasing a voltage checker- it looks like a screwdriver with a pigtail of wire with an alligator clip on the end. The tip of the 'screwdriver' has a point for probing. The light in the probe will light up...makes it easy to trouble shoot without a helper behind the trailer.
Hook the aligator clip to a good positive grounding point on the bumper or frame(not painted).
then pin by pin on the truck connection, stick the probe on each terminal tab.. and write a simple diagram where you find brake, tail, backup, etc...
Then i'd suggest, taking the connector off of your trailer, exposing the wire ends.
Run again thru your diagram and turn on each light of the truck. As you do, touch the wires from the trailer to that specific terminal. (make sure your ground wire is attached on the trailer) you can mark each wire with a piece of tape and label it which is which.
then simply attach your trailer wires according to your diagram to the terminals in the connector... that should get you in business..
hope that makes sense...
That way if the factory wiring harness remains the same, you'll be able to use it with other trailers if the need arises..