No brakes on trailer

crazyro wrote:

Beaker wrote:
Factory integrated brake controller on my truck was causing same message on mine.

Argh. RAM apparently has had some issues with this. I just tested the truck 7 pin and with brakes depressed or brake controller fully engaged, I'm only getting 1/2 V on the ground and brake pins.
What was your solution?

Guess I should have also read page 2 of this thread..

That IS "normal operation" of most new IBC and aftermarket brake controllers..

Newer controllers are "smart controllers" and they are able to "detect" a load on the brake wiring. With no load, the controller will not "send" any power.. The small 1/2V you are seeing is the pulse the controller is sending out to see if there is a load. This makes those "plug in testers" pretty much a useless device since those testers do not simulate a sufficient load to trick the IBC into thinking brakes are attached.

As a side note, starting with 2019 Fords they now have expanded the load thing to the lighting circuits and you WILL get a "light out message" for the trailer.. Does come in handy for stop/turn lights so you are aware of a malfunction.

Newer brake controllers also do not send a straight voltage, they use a PWM output (Pulse Width Modulated) which is a fancy way of saying the voltage is turned on off in a series of pulses. Small short pulses for low braking and to increase the braking the width (time) the pulses are on gets larger giving more overall braking effort..

Ford also reduces the output when sitting still, assuming Ram does similar thing so testing the brake controller functions while parked are pretty much impossible..

The only way to troubleshoot and diagnose a IBC problem is to drive around with a trailer connected or build a test rig with resistors and lights and a meter that present enough load to trigger trailer connected response and drive around..