Chrysler RB1 Navigation, Steering Wheel Controls, 06 Wrangler - FYI

I installed the Chrysler RB1 Navigation Radio along with steering wheel controls in my 2006 Wrangler. This required the use of a body control module from a '99 -2004 Jeep Grand Cherokee to accomodate the signals from the steering wheel switches. I got everything wired and it works like a charm except the display screen. When I start the engine and while  the engine is running, the brightness of the screen fluctuates between bright and dim, but the controls on the radio such as volume, etc. still can be dimmed or brightened with no issue. It is only the screen that fluctuates.  This continues until I move the dimmer switch to the brightest setting just before the interior lights come on. Then the screen stays bright with no fluctuation. However , f the engine is not running or I am using the ACC side of the ignition switch, then the screen can be dimmed or brightened as much as needed without fluctuating between bright and dim.