WHY DO MY LOCKS CYCLE ON AND OFF REPEATEDLY?

The most likely culprit is a faulty actuator. You can test this by having someone activate the rear hatch while listening for a click or sound of some sort. If there is sound but no opening, it indicates a bad latch actuator. If there is no noise, it could be a fuse or wiring issue. You can manually unlock the door by removing the trim, but be careful around the glass latch as there are 2 push pins.

https://www.autogenius.info/chevrolet-suburban-2006-fuse-box-diagram-2/


Check the wiring in the boot that runs from the body to the top of the liftgate for broken wires.

You might have to take it to a collision shop. Remove the rear hatch panel to gain access to the latch assembly if it's not responding. If you can't get it open, take it to a collision shop as they deal with these kinds of things regularly.

Door Lock System Components
The power door lock system consists of the following components:
• Driver Door Module (DDM)
• Passenger Door Module (PDM)
• Liftgate Module (LGM)
• Door lock relay
• Door unlock relay
• Body Control Module (BCM)
• Reversible door lock actuators in each of the doors
• LR/RR LOCKS 10A fuse (relay supply voltage)
• Door lock switches in driver and passenger doors (switches are integral components to the DDM and PDM)

Power Door Lock Operation
The power door lock switches are integral components of the DDM and PDM. The switches are two position normally open rocker switches. When placed in either the lock or unlock positions, the switches provide a direct input to the DDM or PDM. The DDM or PDM monitors these inputs and sends a Class 2 message indicating a change in the switch's respective position. Modules which activate the power door lock motors receive the Class 2 message and activate the motor in the appropriate direction to lock or unlock the vehicle's doors and liftgate. The modules which activate the power lock motors are:
• DDM (driver door lock actuator).
• PDM (passenger front door lock actuator).
• BCM (both rear door lock actuators).
• LGM (liftgate door lock actuator).

Could be a lot of thing's causing it not to work . The way we would diagnose is to hook up a scan tool an look for a DTC - diagnostic trouble code in the lift gate control module first ,no codes ,look at a wiring diagram an test voltages at the lock actuator ,switch etc... Also look on scan tool data to see if the lock/unlock command is getting to the lift gate module .

Door Lock System Components
The power door lock system consists of the following components:
• Driver door module (DDM)
• Passenger door module (PDM)
• Door lock relay--Located in the instrument panel (I/P) fuse block and controls the locking of the rear doors.
• Door unlock relay--Located in the I/P fuse block and controls the unlocking of the rear doors
• Body control module (BCM)
• IP BEC
• Reversible door lock actuators in each door

Driver and Passenger Lock System Operation
The front power door lock switches are integral components of the driver door module (DDM) and passenger door module (PDM). The switches are two-position normally open rocker switches. When placed in either the lock or unlock positions, the switches provide a direct input to the DDM or PDM. The DDM or PDM monitor these inputs and send a LAN message indicating a change in the switch position. Modules, that activate the power door lock motors, receive the LAN message and activate the motor in the appropriate direction to lock or unlock the vehicle doors. The body control module (BCM) upon receipt of a lock or unlock signal will control the rear door lock or unlock relays and also send a LAN message to the DDM and PDM to perform the commanded function.
The modules that activate the power door lock motors are:
• DDM (driver door lock actuator)
• PDM (passenger front door lock actuator)
• BCM (both rear door lock actuators)
The DDM and PDM are directly connected to the respective door lock actuator through the door lock motor lock and unlock circuits. Once a door lock or unlock request has been received, the module will supply battery voltage to one side of the actuator and ground the other, causing the doors to lock or unlock.
The rear passenger doors are controlled by the BCM through the rear door lock/unlock relay which is incorporated onto the printed circuit board in the LH BEC. The BCM controls the unlock relay by providing ground to energize the coil and controls the lock relay by providing battery voltage to energize the relay coil. This energizes the relay and allows voltage to be applied to either the door lock motor lock or unlock circuits. Since the other side of the door lock actuator is connected to the normally closed contacts of the opposing relay to ground, the doors lock or unlock.

Power Door Lock Operation
The vehicle is equipped with power door locks. Each lock actuator is powered and controlled by the door module mounted in the individual door, but the rear integration module (RIM), which is the master control for the door lock system, determines when the lock functions are permitted. The RIM receives and examines the requested lock function from the individual door modules, or from the remote function actuator (RFA) via the class 2 serial data circuit. The RIM also examines the transmission shift selector position and the ignition switch position information available over the Class 2 serial data circuits. If the RIM determines that a lock or unlock function is permitted, it sends a class 2 message back to the individual door modules commanding them to perform that Lock or Unlock function.
Power Door Lock Components
The power door lock system consists of the following components:
?€¢
Driver door lock switch

?€¢
Passenger front door lock switch

?€¢
LH rear door lock switch

?€¢
RH rear door lock switch

?€¢
LH middle door lock switch (w/ V4U)

?€¢
RH middle door lock switch (w/ V4U)

?€¢
Driver door switch assembly (DDSA)

?€¢
Driver door module (DDM)

?€¢
Passenger front door module (PDM)

?€¢
LH rear door module (LRDM)

?€¢
RH rear door module (RRDM)

?€¢
Left middle door module (LMDM) (w/ V4U)

?€¢
Right middle door module (RMDM) (w/ V4U)

?€¢
Driver door lock actuator

?€¢
Passenger front door lock actuator

?€¢
LH rear door lock actuator

?€¢
RH rear door lock actuator

?€¢
LH middle door lock actuator (w/V4U)

?€¢
RH middle door lock actuator (w/ V4U)

?€¢
Driver door cylinder unlock switch

?€¢
Rear integration module (RIM)

?€¢
DRVMDL fuse (10-amp)

?€¢
PASS MDL fuse (10-amp)

?€¢
RRDR MDL fuse (10-amp)

?€¢
Class 2 serial data link

From where , any switch ? driver door switch or either passenger door switch . This is a very complex system controlled by modules (microprocessors)
?€¢
The driver door switch assembly (DDSA)

?€¢
The driver door module (DDM)

?€¢
The passenger door module (PDM)

?€¢
The rear door module (RDM)

?€¢
The LH front power door lock switch

?€¢
The RH front power door lock switch

?€¢
The LH front door lock actuator

?€¢
The RH front door lock actuator

?€¢
The LH rear door lock actuator

?€¢
The RH rear door lock actuator

?€¢
The remote control door lock receiver (RCDLR)

?€¢
The power door serial data circuit

?€¢
The class 2 serial data circuit

?€¢
The DRVMDL Fuse - 10 amp

?€¢
The PDM Fuse - 10 amp

?€¢
The RRINMDL Fuse - 10 a
Class 2 and Power Door Serial Data Links
The class 2 and power door data circuits are both serial data links. The serial data circuits replace cables in the vehicle by multiplexing (time-sharing) data to and from each device over a single wire referenced to ground. If the power door serial data is lost, both the rear door module (RDM) and the passenger door module (PDM) enters the sleep mode. With the RDM and the PDM in sleep mode, no power door operations are possible.
Your best bet is to take it to the dealer or an ASE certified repair shop .

You need to understand how they work , do you know about automotive electronic controls ? Your switches are just inputs to the BCM - body control module !
Door Locks Power and Ground
For door lock operation, the IP Fuse Block supplies battery positive voltage, through the 15 amp DR LK/TRUNK fuse, to the BCM. The BCM uses this circuit exclusively to apply power to the door lock actuators. The BCM is also supplied a ground circuit, which it uses exclusively to ground the door lock actuators. When a door lock is pulsed, the BCM internally connects these two circuits to the appropriate lock and unlock control circuits to actuate the locking or unlocking functions.
When diagnosing door lock malfunctions, these circuits must not be confused with the other battery voltage and ground circuits of the BCM. The appropriate wiring schematic must be used to locate the correct circuits. Failure to identify the correct battery voltage and ground circuits of the BCM during diagnosis of door lock concerns may result in misdiagnosis and unneccessary parts replacement.
Passenger Door Unlock Operation
When the BCM detects a transition of either of the door lock switches to the Unlock position, it switches the door lock actuator unlock control circuits to voltage. Since the door lock actuator lock control circuit is at ground potential within the BCM, the passenger door lock actuators transition to the Unlock position.
The door lock actuator unlock control circuits are dedicated control circuits used only for the passenger door lock actuators. This is done so that the driver door may be unlocked individually before unlocking the passenger doors using a keyless entry transmitter or an automatic door unlock function, if programmed. When the keyless entry transmitter is used to unlock the passenger doors, the BCM requires a repeated unlock command before it performs the unlock function. However, when the unlock input is from a door lock switch, a single unlock command is all that is required to unlock all doors.

How to test computer controlled door locks

When you hit the unlock/lock repeatedly can you hear that doors lock actuator moving ? it might have become disconnected or 1 of the 2 wires may have come loose

Do the power windows work ? DDM - driver door module fuse 15 amp - location is the instrument panel fuse box , plus LT DR circuit breaker 25 amp. Circuit breakers rarely go bad . The power locks are controlled by electronic's .The passenger side has another power supply ,that's why they still work .
Door Lock System Components
The power door lock system consists of the following components:
• The driver door switch (DDS)
• The passenger door switch (PDS)
• The body control module (BCM)
• The driver information center (DIC)
• The rear door lock/unlock relay (LBEC)
• The reversible door lock actuators in each of the doors and liftgate

The front power door lock switches are integral components of the driver door module (DDS) and passenger door module (PDS). The switches are 2 position normally open rocker switches. When placed in either the lock or unlock positions, the switches provide a direct input to the DDS or PDS. The DDS or PDS monitors these inputs and sends a LAN message indicating a change in the switch's respective position. Modules which activate the power door lock motors receive the LAN message and activate the motor in the appropriate direction to lock or unlock the vehicle's doors and liftgate. The rear door lock switch provides a lock and unlock signal to the body control module (BCM). The BCM upon receipt of a lock or unlock signal will control the rear door lock/unlock relay and also send a LAN message to the DDS and PDS to perform the appropriate function.
The modules which activate the power lock motors are:
• The DDS (driver door lock actuator)
• The PDS (passenger front door lock actuator)
• The BCM (both rear door lock actuators and cargo door/liftgate)
The DDS and PDS are directly connected to the respective door lock actuator through the door lock motor lock and unlock circuits. Once a door lock or unlock request has been received, the module will supply battery voltage to one side of the actuator and ground the other causing the doors to lock or unlock.
The rear passenger and endgate doors are controlled by the BCM through the rear door lock/unlock relay which is incorporated onto the printed circuit board in the LH BEC. The BCM controls the unlock relay by providing ground to energize the coil and controls the lock relay by providing battery voltage to energize the relay coil. The energized the relay and allows voltage to be applied to either the door lock motor lock or unlock circuits. Since the other side of the door lock actuator is connected to the normally closed contacts of the opposing relay to ground, the doors lock or unlock.

It's possible you have broken wire or wires inside the flex boot from the body of the vehicle to the driver's door . This happens a lot .
Fuse Block - I/P instrument panel
Left of the I/P behind the side trim panel

If it doesn't work from master switch then the door lock motor actuator will need to be replaced, this requires pulling the door panel.