The RAM brake controller is a digital system. The output is PWM (pulse width modulated) - it changes the duty cycle of the output proportional to the demand. For that reason, it's hard to read the output with a multimeter.
RAM is aware of the problem. I understand there have been complaints to the NHTSA about it. Yes, it would be nice if they fixed it.
In the meantime, try running your system in the HEAVY-ELECTRIC-OVER-HYDRAULIC mode (even though you don't have hydraulic brakes), instead of HEAVY-ELECTRIC. Not sure WHY it works (something in the software/programming), but it does. I'm able to run mine at 8.5 instead of 10. It still won't completely lock them up (even using a setting of 10), but it comes close. 8.5 for me is a good setting that allows the trailer to "stop itself".
Also, the others are correct about burnishing new brakes, but if yours have been seated, and adjusted properly, then try this setting.
If all else fails, etrailer does have a wiring adapter to convert your factory controller to an analog system like Tekonsha.
