How Much Amperage Should 4 Trailer Brake Magnets be Drawing

Published 08/25/2015

Products Featured in This Question

Tekonsha Prodigy P3 Trailer Brake Controller - 1 to 4 Axles - Proportional

(6644)

$156.06

Brake Adjustment Spoon for Drum Brakes

(219)

$8.08

Question:

How much voltage should be at the brake wire close to the magnet with the brake controller maxed out this trailer has two axles with four brakes and they pull about 15 amps

asked by: Stacy P

Expert Reply:

For a trailer with 4 brake assemblies (10 or 12 inch assemblies) you should be seeing 15 to 16.3 amps at 12 to 13 volts. If the trailer has 7 inch assemblies it would be lower, 12.6 to 13.7 amps at 12 to 13 volts.

Individual magnets on 10 or 12 inch assemblies should show 3.2 to 4 amps and on 7 inch assemblies you should see 3 to 3.2 amps.

If your trailer brakes seem weak then you may just need to adjust the brakes. To see how to manually adjust trailer brake assemblies check out the video I attached, fast-forward to the 4:35 mark of the video. If you need an adjustment tool use # W80630.

expert reply by: Michael H