Bcm failure Truck alarm sounds at random and when the key is taken out of the ignition it is not registering, so the lights, stereo, alarms etc... keep going off. Thinking it's the BCM. Anyone have any ideas?

Try shutting it off with the door key . Lock and unlock the drivers door with it.

Sound like you have ignition switch problem. You can start with remote then everything should be fine.

This sounds like a bad alarm module. the alarm should not sound with acc or ignition power to module, you can check wiring to module but i would say its a module.this truck didnt come with a factory alarm so this must be an aftermarket install, i would remove it or just cut power to module. the module will be located under the driverside dash area.

another case of boy racer alarm problems ,this vehicle is fitted with a factory immobilisor ,if i wanted to steal this car the alarm wouldnt stop me i would just lift vehicle up with a flatbed breakdown truck and no one would even look twice .best deterrent is a krooklock on the steering wheel and keep the key seperate from the ignition key,most vehicles are stolen with a house break in for the key ,criminals are smart and know they cannot get past the immobilisor .also keep a spare krooklock key in the vehicle and do not tell anyone

ALL YOU NEED TO DO IS LOCK AND UNLOCK THE DRIVERS DOOR WITH THE KEY, THIS DEACTIVATES THE FACTORY ALARM SYSTEM, AND YES YOUR VAN DOES HAVE A SECURITY SYSTEM AND A TRANSPONDER KEY, IF THE PROBLEM CONTINUES YOU WILL NEED TO HAVE THE DEALER RECHECK THE WORK THEY DID, THEY HAVE TO PROGRAM THE MODULE FOR YOUR CARS SECURITY CODE, MAYBE THEY DID THAT WRONG, UNTIL THEY RETEST THE BCM THERE IS NO WAY WAY TO KNOW WHAT THE PROBLEM IS HERE, THE BCM CONTROLS THE FACTORY SECURITY SYSTEM ON THIS VAN, SO ASSUME THE PROBLEM IS WITH THE NEW BCM'S PROGRAMMING...

The Body Control Module (BCM) controls the audible warnings. Refer to Body Control System Description in Body Control System for more information regarding the BCM.
The body control module (BCM) controls these reminders:
• Key in ignition reminder: An audible warning intended to remind the driver that the key has been left in the ignition cylinder. The BCM sounds the chime for this reminder at a rate of 150 chimes per minute.
• Fasten seat belt reminder: An audible warning intended to remind the driver at the beginning of the driving cycle that the driver's seat belt is unfastened. The BCM sounds the chime for this reminder at a rate of 50 chimes per minute.
• Fasten belts indicator control: A visual warning intended to remind the driver that the driver's seat belt is unfastened.
• Parking brake reminder: An audible warning intended to remind the driver that the parking brake has been left applied with the transaxle shifted out of PARK. The BCM sounds the chime for his reminder at a rate of 200 chimes per minute.
• Turn signal reminder:
An audible warning intended to remind the driver that the turn signal has been left on while the vehicle has traveled over 1.2 km (¾ mile). The BCM sounds the chime for this reminder at a variable rate (in unison with the turn lamps on) of 90 chimes per minute.
• Headlamps ON reminder: An audible waring intended to remind the driver that the headlamps have been left on. The BCM sounds the chime for this reminder at a rate of 200 chimes per minute.
• Last door closed locking confirmation: An audible warning intended to provide the driver feedback that the last door closed locking feature is active. The BCM sounds the chime for this remainder at a rate of 200 chimes per minute.
• Feature customization and diagnostics feedback: An audible feedback used when changing feature customization modes. Also used by service technicians during the BCM diagnostics. The BCM sounds the chime during the feature customization, and also during diagnostics. Refer to Body Control Module (BCM) for additional information.

Step
Action
Value(s)
Yes
No
1
Was the BCM diagnostic system check performed?
--
YES - Go to Step 2
NO - Go to Diagnostic System Check - Body Control System in Body Control System
2
Check for Powertrain Control Module (PCM) Diagnostic Trouble Codes (DTCs). Refer to Powertrain On Board Diagnostic (OBD) System Check (LX5) or Powertrain On Board Diagnostic (OBD) System Check (L36) in Engine Controls for more information.
Are there any PCM DTCs present?
--
Go to Appropriate DTC Table in Engine Controls
Go to Step 3
3
Connect a scan tool to the Data Link Connector (DLC).
Using scan tool, select BCM data display inputs and monitor the park brake switch input.
While observing the scan tool, apply and then release the park brake.
Does the scan tool indicate that the park brake input is off while the park brake is released?
--
Go to Step 7
Go to Step 4
4
Turn the ignition switch off.
Disconnect the scan tool from the DLC.
Disconnect the BCM connector C1.
Release the park brake.
Using a test light, connect between B+ and the BCM connector C1 terminal D5.
Is the test light off?
--
Go to Step 7
Go to Step 5

Your best bet ,take it to a qualified repair shop

get a new battery for key then put key in ignition and turn on and off 3x times and that should reset alarm

sounds like the factory alarm is keeping it from starting.

My 1991 Lexus LS 400 does something similar. When the alarm goes off I use the key to unlock the passenger side front door and it turns the alarm off. Go figure, I know it sounds funny but it solves the problem for me.

sounds like you have an aftermarket alarm not factory most of these alarma are equipped with a starter interupt that will not vehicle start. when connecting the battery ist is normal for the alarm to sound some alarms may not sound if ignition is on while connecting battery, however this is not reccomended. after connecting battery and alarm sounds you should be able to turn it off with trasmitter, if you do not have one then you will need to put key in ignition turn it on and look under the dash for a valet switch or togle switch this may override the alarm and let car start if you cannot locate this you can alway locate the alarm box under dash and unplug it as last resort most alarm defaults will let the car start when this is done. hope this helps