Troubleshooting Bad Ground on Trailer Brake Circuit
Question:
What can we do to fix and will our braking system still work
asked by: Diane H
Expert Reply:
With the Prodigy P2 trailer brake controller # 90885 the troubleshooting code 9 indicates that the controller detects the connected trailer but is losing its ground connection to the host vehicle. This ground connection is essential for the unit to deliver braking power to the trailer through the 7-way connection.
All brake controllers use the same 4-wire color-coded connections. Red wire for brake light signal; blue wire for output; black wire for 12V operating power; and the WHITE wire is ground. This wire needs to connect to the battery ground. The ground connection can be made through a vehicle's under-dash brake controller connection port (for popular tow-capable vehicles like a pickup truck that have this feature) or it can be a hardwired connection direct to the battery ground terminal if the controller was installed by hardwiring it. Either way, that white ground wire must be solidly connected to the battery ground. So what you want to do is try to find the connection point in the wiring where the ground is being lost.
If your vehicle uses an under-dash connector for the controller you can unplug this from both the under-dash port and from the back of the controller to check the two contacts for the white wire. A corroded or bent contact could be the issue.
Also check the 7-way socket on the back of the vehicle for the same potential corrosion issue and for a bent pin. Check the main ground wire on the trailer where it connects to the frame and the ground contact on its 7-way plug.
Product Page this Question was Asked From
Tekonsha Prodigy P2 Trailer Brake Controller - 1 to 4 Axles - Proportional
- Trailer Brake Controller
- Proportional Controller
- Electric
- Electric over Hydraulic
- Automatic Leveling
- Under-Dash Box
- Dash Mount
- Up to 4 Axles
- LED Display
- Up to 360 Degrees
- Tekonsha
more information >
Featured Help Information
Instructions
Miscellaneous Media
Continue Researching
- Shop: Brake Controller
- Article: Testing Trailer Brake Magnets for Proper Function
- Shop: Tekonsha Prodigy P3 Trailer Brake Controller - 1 to 4 Axles - Proportional
- Search Results: 10000 lb axle kit
- Shop: etrailer Electric Trailer Brakes w/ Dust Shields - Self-Adjusting - 12-1/4" - Left/Right - 10K
- Shop: Bearing Kit, 14125A/ 25580 Bearings, 10-36 Seal
- Shop: Replacement Trailer Hub Bearing - 25580
- Shop: Bearing Kit, 14125A/25580 Bearings, GS-2125DL Seal
- Shop: etrailer Electric Trailer Brakes - Self-Adjusting - 10" - Left/Right Hand Assemblies - 3.5K
- Shop: Replacement Oil Cap Kit for 9,000-lb to 15,000-lb Dexter Axle
- Q&A: Is There a Way to Tell Difference Between 12k and 15k Trailer Brake Assemblies
- Video: Hopkins LED Breakaway Switch Review
- Search Results: 10000 lb hubs
- Search Results: 25580 bearing
- Search Results: 10k dexter axle bearing kit
- Q&A: Availability of Electric 6 Bolt Mount Brake Assemblies for 10K Axle
- Q&A: Recommended Timken Races And Bearings For A Dexter Axle
- Q&A: Does Race Need To Be Replaced If Installing New Bearings
- Shop: Camper Tie-Downs
- Shop: Suspension Enhancement
- Video: TorkLift StableLoad Rear Suspension Upgrade Installation - 2018 Ford F-350 Super Duty
- Video: Review of TorkLift Vehicle Suspension - StableLoad Suspension Upgrade - TLA7200
- Video: TorkLift StableLoad Rear Suspension Upgrade Review
- Search Results: tlf3008
- Search Results: tla7311s
- Search Results: a7312s
- Q&A: Troubleshooting Trailer Brakes After Installing a New 7-Way Trailer Connector
- Article: Testing Brake Controls
- Q&A: How to Test Brake Magnet Amperage on a Trailer with 4 Brakes
- Q&A: Should Electric Trailer Brakes Have Continuity Between The Two Wires?
on Trailer Brake Controller
