Trailer Brake Lights Not Working when Connected to 2004 Porsche Cayenne S with Factory Tow Package
Updated 05/16/2016 | Published 05/12/2016
Products Featured in This Question
Question:
Hi there, I had a problem back in 2011 with no backup or tail lights. The trailer I had then had electric brakes and I couldnt go in reverse the brakes locked up because no power to backup lights. The local Austin Porsche dealer replaced part #955-618-040-10 control unit. Im assuming that everything worked then. Everythings fine on Porsche. The running lights, and brake lights work on trailer but no brake lights on trailer. I now have a trailer with drum hydraulic brakes and it works fine with my sons 97 Chev C1500. The Porsche has a 7 round and I use an adapter to my four flat which the Chevy has. I would start checking fuses if I knew which ones and their location. Any help would be appreciated.
asked by: Gary T
Expert Reply:
The first place I recommend checking is the trailer connector on your 2004 Porsche Cayenne without the adapter or trailer plugged in. Use a circuit tester such as # PTW2993 to test the pins in the 3 o'clock and 9 o'clock positions while someone sits in the vehicle and presses the brake pedal.
If there is no power on those pins during this test then it could be a fuse or relay related to the tow package wiring. Your Cayenne has a fuse box under the hood and in the cab on each end of the dash. On the right side of the dash there are tow package fuses in locations 1, 3, 5, 19, and 41. there aren't any in the other fuse panels. Any relays associated with the tow package wiring would need to be handled by a Porsche dealer as specified by the owner's manual.
If there is power on the trailer connector pins then plug in the adapter you have and test the output side of the adapter. If there is no power on the output side then the issue is with the adapter and it will need to be replaced with a new one such as # C35FR.
If there is power on the output side of the adapter then the issue is on the trailer; likely a bad ground or corroded trailer connector. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light but can show up any time.
Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces.
The light grounds should also be attached to clean and corrosion free bare metal surfaces. If there is anything between a light ground and the metal trailer frame or if the trailer has an aluminum frame, tilt bed, or folding tongue, any of these things can interrupt the ground. Running jumper wires from the light grounds to the main trailer connector ground can help.
Product Page this Question was Asked From
7-Way to 4-Way/5-Way Trailer Adapter for Vehicles with Lamp-Out Sensors Towing Trailers with LEDs
- Custom Fit Vehicle Wiring
- Wiring Adapters
- Universal Fit
- 7 Blade to 4 Flat
- 7 Blade to 5 Flat
- Plug Only
- CURT
more information >
Continue Researching
- Search Results: tow ready 20142
- Video: A Closer Look at the 7-Way Trailer Adapter for Towing Trailers with LED Lights
- Shop: Trailer Wiring
- Shop: TowSmart Trailer Connector Adapter - 7-Way RV to 6-Way Round
- Shop: 7-Way to 4-Way/5-Way Trailer Adapter for Vehicles with Lamp-Out Sensors Towing Trailers with LEDs
- Shop: 7-Way Trailer Adapter for Towing Trailers with LED Lights
- Shop: Trailer Hitch
- Shop: Curt Powered Tail Light Converter with 4-Pole Flat Trailer Connector
- Search Results: trailer hitch
- Q&A: What is the Difference Between a Class II and a Class III Hitch?
- Video: Firestone Ride-Rite Air Bags with Easy Mount Compressor Feature Breakdown
- Article: Trailer Wiring Diagrams
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Shop: Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires
- Search Results: trailer wiring
- Q&A: What is the Difference Between a 4-Way and 7-Way Trailer Connector
- Q&A: Lug Nut Torque Chart for Trailer Wheels
- Shop: Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
- Search Results: trailer tires and wheels
- Article: How to Measure for Trailer Hitch Drop
- Shop: Suspension Enhancement
- Video: How to Choose a Trailer Brake Controller
- Q&A: Installation Time for Blue Ox BX1128 Flat Tow Base Plate Kit for 2016 Jeep Grand Cherokee
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Search Results: trailer jack
- Video: Curt T-Connector Vehicle Wiring Harness Review C56040
- Shop: etrailer Trailer Hitch Receiver - Custom Fit - Matte Black Finish - Class III - 2"
- Shop: Brake Controller
- Article: How to Choose the Right Trailer Hitch Class
- Search Results: trailer lights
on Custom Fit Vehicle Wiring
