Trailer break problem. I need help, I;='m Stumped

[sb47]

Hey folks I need help on my trailer. It has breaks and they were working fine, then they seemed to just stop working. My breaks work just fine on my cargo trailer but not on my flat bed. I’ve tried everything I know to do but still can’t get them to work. I checked the voltage at the actuator and its getting voltage there but the breaks dont engage.
I have brand new actuators that I bought to replace the old ones but I feel like since I’m getting 12 volts to the old ones that I may not need to put the new ones on.
This trailer does not have break away battery on it so thats not the problem.
The lights work, the turn signals work and the break lights work, but not the breaks.
I’m stumped.

Can anyone give me any ideas?

 

[mopar3]

Trailers are notorious for bad connections and poor gounds. So look really hard at for any spread terminals or chaffed wiring. You can have 12v at the actuators but not enough current to do anything. I like to test wiring with a fog lamp or headlamp type bulb as a test lamp. It actually load tests the circuit to see if it can carry current. You can have a wire that is a green corroded turd and measure 12v on it but it wont light up a fog light.

 

[PasoRoblesJimmy]

Trailers are notorious for corroded connections. Unsealed, poorly-sealed and non-weatherproof connections on trailers and tow vehicles are a recipe for failure.

Undersized wires are also a problem. Tinned wire resists corrosion better than untinned.

Grounds should be implemented through grounding wires in the trailer to tow vehicle connectors and not the frame of the trailer nor the frame of the tow vehicle.

 

[Goose IBEW]

Very good info^^^^^^^^^^^^^^^^^