Troubleshooting Electric Trailer Brake Assembly Magnets
Question:
I have a two axle trailer with 12” electric brakes. I’m getting 8 amps out of the brake controller at 12 volts. I checked the resistance at the trailer plug blue and white wire. It was 2.4. I disconnect each magnet and tested for ohms. Each one came back 3.8-4.0, expect for one that was open. I replaced that magnet and retested at the trailer plug. The resistance went down to 1.6. I’ve been trying to find the answer to this one simple question, but no one seems to know it or even ask the question. Does the resistance go up or down when connecting multiple magnets? I would think the better the connection, the lower the resistance. But don’t know for sure.
asked by: Mike
Expert Reply:
We have an article to assist with checking your brake magnets like you are stating. The resistance will go down because the brake magnets are connected in parallel. Since the voltage doesn't change, the amperage draw needs to increase to power the magnets. This is Ohms law in action based on my research.
You obviously already have a multimeter like # PT89ZR so if you determine based on the article that you need to replace magnets, I recommend # BP01-180 for 12 inch Dexter assemblies or # AKBRKR-M12 for a more cost effective alternative.
Products Referenced in This Question
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 >
Replacement Trailer Brake Magnet for 12" Brake Assemblies
- Accessories and Parts
- Trailer Brakes
- Electric Drum Brakes
- Brake Magnets
- 12 x 2 Inch
- Redline
more information >
Digital Multimeter with 42" Long Test Leads - LED Display
- Electrical Tools
- Testers
- Multimeter
- Yellow
- Performance Tool
more information >
Product Page this Question was Asked From
Dexter Electric Trailer Brakes - 12" - Left/Right Hand Assemblies - 6,000 lbs
- Trailer Brakes
- Electric Drum Brakes
- Standard Grade
- Manual Adjust
- 12 x 2 Inch Drum
- 6000 lbs Axle
- 14-1/2 Inch Wheel
- 15 Inch Wheel
- 16 Inch Wheel
- Dexter
more information >
Featured Help Information
Instructions
Miscellaneous Media
Continue Researching
- Shop: Dexter Electric Trailer Brakes - 12" - Left/Right Hand Assemblies - 6,000 lbs
- Article: Testing Trailer Brake Magnets for Proper Function
- Search Results: cotter pin
- Video: Dexter Electric Trailer Brake Kit Installation 23-26
- Q&A: Replacement Brake Assemblies for 12 inch by 2 inch AL KO 5,200 lb Trailer Axle
- Search Results: 23~105~106
- Video: Review of Dexter Axle Trailer Brakes - 12 inch Electric Drum Brake Kit - 23-105-106
- Shop: Dexter Electric Trailer Brake Assembly - 12" - Right Hand - 6,000 lbs
- Shop: Dexter Electric Trailer Brake Assembly - 12" - Left Hand - 6,000 lbs
- Shop: Replacement Shoe and Lining Kit for 12" Manual-Adjust Brake Assembly - 5,200 lbs to 7,000 lbs
- Shop: Dexter Electric Trailer Brakes - 12" - Left/Right Hand - 6K AL-KO/Hayes Axles
- Shop: Replacement Trailer Brake Magnet for 12" Brake Assemblies
- Shop: Replacement Magnet Kit for 12" Electric Trailer Brake Assemblies - 5,200 lbs to 7,000 lbs
- Q&A: Torque For Dexter 12 Inch Brakes 23-105-106
- Q&A: Cotter Pin Replacement Part for 5,200 lb Axles
- Q&A: Torque Specs for Trailer Wheel Lug Nuts
- Q&A: Tips for How to Identify a Trailer Axle
- Q&A: Lug Nut Torque Chart for Trailer Wheels
- Video: Trailer Brake Controller Wire Testing
- Q&A: What Amperage Draw Does Brake Controller Look for on Trailer Wiring to Sense Connection
- Search Results: stereo
- Search Results: shadeblade
- Search Results: 44649
- Article: Trailer Wiring Diagrams
- Shop: Trailer Hitch
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Shop: Trailer Wiring
- Search Results: 25580
- Article: Most Popular Wheel Bearings
- Shop: Brake Controller