DIC periodically goes beserk and displays "trunk open" and "door ajar" when in fact they are not. Door locks operate independently while I am cruising along. Interior lights come on and stay lit after parking and exiting. Is this someking of cluster problem or what?

There is no BODY CONTROL module,but there is a Front Electronic module FEM, and a rear electronic module,REM (not the rock group,LOL!).
The FEM is located behind the driver's kick panel and the FEM is located on the right side down in the trunk.
The REM controls: Rear windows, , all rear lights, trunk opening, fuel door release, rear window defrost grid, trunk ajar switch, front passenger door lock, , front passenger door lock switch,rear door locks, trunk light, fuel pump, fuel level senders, antenna booster.

Hope this helps? don-ohio (:^)

It should tell you which one .
Driver Door Ajar Malfunction
Passenger Door Ajar Malfunction
If not a scan tool would be the best way.
Ignition ON, observe the scan tool Driver Door Ajar Sw parameter while opening and closing the driver door. The parameter should change between Door Closed and Door Ajar
? If the parameter does not change, refer to Driver Door Ajar Malfunction.
With the passenger doors closed, observe the scan tool Door Ajar Switch parameter while opening and closing each door. The parameter should change between Door Closed and Door Ajar.
? If the parameter does not change, refer to Passenger Door Ajar Malfunction

Ignition OFF, disconnect the harness connector at the driver door latch.
Test for less than 5 ohms between the ground circuit terminal 8 and ground.
? If greater than the specified range, test the ground circuit for an open/high resistance.
Ignition ON, verify the scan tool Driver Door Ajar Sw parameter is Door Closed.
? If not the specified value, test the signal circuit terminal 6 for a short to ground. If the circuit tests normal, replace the BCM.
Install a 3A fused jumper wire between the signal circuit terminal 6 and the ground circuit terminal 8. Verify the scan tool Driver Door Ajar Sw parameter is Door Ajar.
? If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
If all circuits test normal, test or replace the driver door latch

Here is how it works !
Liftgate Locking Operation
The lift gate will lock any time the vehicle is shifted out of park on vehicles equipped with an automatic transmission and at vehicle speeds exceeding 5 kph with manual transmission. This happens in conjunction with auto door locks if enabled or independently of auto door locks if the feature is disabled. This ensures that the lift gate is locked anytime the vehicle is shifted out of park or when the vehicle is in motion.
The lift gate lock relay supply and coil sides receive a constant voltage through the battery voltage supply circuit and the ECC fuse. The normally closed contact is connected to ground and the control side is connected to the body control module (BCM). A lock function will occur when a door lock switch activation, keyless entry lock transmission, auto door lock function or a lift gate lock function has been received by the BCM. The BCM will then ground the control side of the lift gate lock relay. This energizes the relay and allows voltage to be applied to the lift gate lock actuator lock control circuit. Since the other side of the lift gate lock actuator is connected to the normally closed contacts of the door unlock relay to ground, the lift gate will lock. When an unlock function occurs the BCM will ground the control side of the unlock relay and the rear doors and lift gate will unlock.
The BCM also runs diagnostics on the lift gate lock relay control circuit and will set DTC B3825 as current and also send a Class 2 message to the DIC. The DIC will display REPLACE LIFTGATE FUSE to inform the driver that a fault has been detected in the lift gate lock circuit and that the lift gate is not locked. Faults that will set the DTC and cause the DIC to display the message could be any of the following:
?€¢
An open ECC fuse

?€¢
An open or short to ground in the lift gate lock relay battery positive voltage circuit

?€¢
A faulty lift gate lock relay

?€¢
An open or short to ground in the lift gate lock relay control circuit

?€¢
A short to ground in the lift gate lock actuator lock control circuit

?€¢
A faulty BCM

Each door ajar switch sends a signal. The signal goes through the window switch for that door, probably be easiest to access the ajar signal wire at the window switch connector on any door.

Something is not telling the car your door is closed check the light switch make sure it's pushing In and properly and getting contact

where the wiring goes from the rear door to the body of the car check for broken wires or take panel of and check all wires for braeks splits or bad connections

Who looked at it ? Dealer ? Did the place's you had look at the vehicle hook up a factory scan tool an view data to door module's an the BCM ? Door ajar is a fuction of the door modules an the BCM - body control module . One of these modules is seeing an input that makes it think door is open .
The door ajar indicator system consists of the following components:
• The driver door module (DDM)
• The passenger front door module (PDM)
• The body control module (BCM)
• The instrument panel cluster (IPC)
• The driver information center (DIC)
• The driver door ajar switch
• The passenger door ajar switch
• The left rear door ajar switch
• The right rear door ajar switch
• The liftgate ajar switch

Driver Door Ajar And Passenger Door Ajar
The DDM and PDM receive a discrete input from the respective door ajar switch to indicate the status of the door. The DDM or PDM then communicates this status to the IPC via class 2 message. The IPC, upon receipt of this class 2 message, will illuminate the appropriate door ajar message in the DIC and also send a class 2 message to the radio to activate the door ajar audible warning when the following conditions are met:
• The transmission is removed from PARK
• The vehicle speed is greater then 8.05 km/h (5 mph)
Left Rear Door Ajar And Right Rear Door Ajar
The BCM receives a discrete inputs from both the left and right rear door and liftgate ajar switches to indicate the status of the doors and liftgate. The BCM then communicates this status to the IPC via class 2 message. The IPC, upon receipt of this class 2 message, will illuminate the appropriate door ajar message in the DIC and also send a class 2 message to the radio to activate the door ajar audible warning when the following conditions are met:
• The transmission is removed from PARK
• The vehicle speed is greater then 8.05 km/h (5 mph)

Could have DTC'S - diagnostic trouble codes . Looking at data paramiters on the scan tool tool would show what switch is faulty or what part is .

Can't help with the antenna. As far as the door ajar goes any of the cars doors can cause this, it is a ting switch that is twist locked into the door latch that fails and gives the warning, it is referred to as the "door ajar switch" You need to have a scan tool hooked up to see which door is causing the problem, as I said any of the four switches can be faulty. Since all the door panels would likely need to come off to find the bad part the scan is the best route.

door jamb switches are bad unplug one at a time till you find it dont forget tailgate

The door latch has a switch built into it to replace the old door jamb switch. If the switch is faulty the system will think the door is ajar. A scanner will show an open switch.

YOU SHOULD BE UNDER WARRANTY.