Troubleshooting Low Output Voltage from Trailer Brake Controller
Question:
Im only getting 9.5 volts out of my brake controller and trailer brakes dont make full contact
asked by: William J
Expert Reply:
Your trailer brake controller should be able to output a full 12V signal when it is set for maximum power/boost. If you are measuring only 9.5V output then try testing right at the blue output wire at the back of the controller with a multi-meter like # PT89ZR while engaging the manual override control. Do this test with full power and boost selected on the controller. If you do not detect 12V here then the controller itself is bad.
If you tested at the vehicle's 7-way then the issue could have other causes. Check the main ground wire for the wiring harness to ensure it is attached to a spot on the vehicle frame that is clean bare metal, free of paint, primer, corrosion or undercoat. Also check the condition of the actual contacts for the ground and the brake circuit on both the vehicle and trailer in case there is trapped material or corrosion present. Electrical contact cleaners like Caig De-Oxit can dissolve corrosion if present.
Please let me know the result of your test on the blue wire and any other details about the vehicle and controller and I can give you additional troubleshooting help. You can also refer to the two linked articles.
Products Referenced in This Question
Digital Multimeter with 42" Long Test Leads - LED Display
- Electrical Tools
- Testers
- Multimeter
- Yellow
- Performance Tool
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Product Page this Question was Asked From
Replacement Magnet Kit for 12" Electric Trailer Brake Assemblies - 5,200 lbs to 7,000 lbs
- Accessories and Parts
- Trailer Brakes
- Electric Drum Brakes
- 5200 - 7000 lbs
- Brake Magnets
- 12 Inch
- etrailer
more information >
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