Changed pads and took it back out of maintenance mode. If i engage the parking brake then turn off car wait 20 seconds and then start it and disengage parking brake, it works, both rear parking brakes engaged and disengaged and both parking brake lights are out. NOW, if you have the engine running and engage parking brake and then disengage it, brake light starts flashing as well as the light on the button. Both brakes are disengaged. When i engage them again, only the driverside rear is engaged and lights still flashing. I disengage the parking brakes and it releases but light still flash. I can replicate this everytime. Downside is you cannot use your cruise control if these lights are still blinking. I shut the car off, wait 20-30 seconds and the lights will go out and your back to normal. Have anyone else ever experienced that.

 

You're having almost the exact same issue as I am. If I engage the e-brake while the car is on, only one side will engage and the lights flash. If I shut the car off, then pull up on the e-brake both brakes will engage and no lights flashing.

I've been suggested to swap out the e-brakes (left/right) to see if the problem follows the motor.

 

Did you ever figure your problem out? Recently I had to change out the rear brakes so I took the opportunity to swap the motors. Unfortunately it didn't make any difference. When the car is off both brakes will engage, but if the car is on only one side will work. I'm wondering if it might be a sensor that thinks the car is moving?