Testing Individual Trailer Brake Magnets or All Brake Magnets at Once

Question:

I read reply by Michael H. Paragraph above 10inch drum amps appears to reference testing each magnet separately but amp table refers to 2-brake, 4-brake, 6-brake setups and related amps. I have a 4 brake 10inch system and wonder whether these can be tested all connected together or do I have to separate wires and check each magnet.

asked by: Don B

Expert Reply:

If you are testing with the trailer connected to the vehicle (the first part of the FAQ, linked for reference) then the max amps at 12-13 volts for 4 brakes TOTAL should be 15-16.3 amps on 10 inch assemblies. This first section explains the process for testing all of the magnets at once.

If you are testing each magnet individually, you should get 3.2-4 amps at 12-13 volts for 10 inch assemblies.

If you are testing for resistance for an individual magnet you will be looking for 3-3.8 Ohms per magnet for a 10 inch assembly.

expert reply by: Michael H