How difficult is it to replace a BCM? Where is it located?

The BCM is located on the back side of the Junction Block (fuse panel located to the left of the steering wheel). To get to it you'll need to remove the Junction Block and then unscrew the BCM from the back of it.
Oct. 13, 2006

Where is the BCM located? - LOST JEEPS • View topic

Videos as well

https://www.google.com/search?q=09+jeep+patriot+BCM+Location

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BCM Replacement
Replace the BCM only if diagnostics in this section directs you specifically to do so. Most system problems are traceable to faulty wiring, to connectors, or to components. The BCM itself is very reliable and is not likely the cause of a fault. Do not replace the BCM before performing a complete diagnosis or recurrence of the fault will likely occur. Note: Every input to the BCM is short to ground and short to battery protected. Every output from the BCM is short to ground and short to battery protected. Therefore, the BCM does not automatically need to be replaced when there is a short found in the wiring connected to it. Repair the wiring first, then check the system for any further problem.

BCM Programming
When a BCM is replaced, it must be programmed with the Vehicle Identification Number (VIN) of the vehicle that it is being installed in. The RadioTheftlock feature uses the VIN to verify that the radio has not been removed and improperly installed in another vehicle.
The programming of the BCM is accomplished by using a scan tool. The vehicles VIN is entered in the scan tool and then transmitted via a Class 2 physical message to the BCM. The BCM stores the VIN in EEPROM. The first communication between the BCM and radio re-arms the Radio Theftlock. To set up a new BCM, select SETUP NEW BCM from the BCM Special Functions menu and follow the instructions on the screen.

Body Control Module (BCM)
Mounted on the RH Kick Pad, behind the trim panel

Remove the radio bezel. Refer to Radio Replacement .
Disconnect the body control module (BCM) electrical harnesses.
Remove the BCM from the instrument panel (I/P) retainer:
3.1. Pry the BCM tabs from the locking tabs on the underside of the restraint.
3.2. Slide the BCM out of the retainer

The BCM needs to be programmed if replaced !
The body control module (BCM) must be programmed with the proper RPO configurations. The BCM stores the information regarding the vehicle options and if the BCM is not properly configured with the correct RPO codes, the BCM will not control all of the features properly. Ensure that the following conditions exist in order to prepare for BCM programming:
• The battery is fully charged.
• The ignition switch is in the ON position.
• The data link connector (DLC) is accessible.
• All disconnected modules and devices are reconnected before programming.
The following procedures need to be performed to properly configure a BCM:
BCM Programming
Passlock Learn
Program Key Fobs

Body Control Module (BCM)
In the center of the I/P, behind the HVAC control module

Chrysler Mini-Van Body Control Module (BCM) Replacement

www.jamesmskipper.us/AutoRepair/BCMReplacement.html
BCM REPLACEMENT. It is difficult to diagnose BCM problems. 10/13/13 - Early this year I had the car towed to a dealer, and they fixed it. But they first installed ...

The 15-amp STOP fuse located in the body control module (BCM) supplies battery positive voltage to the normally open stop lamp switch. When the driver presses the brake pedal, the switch contacts close and battery positive voltage is supplied to both left and right stop lamp assemblies and the center high mounted stop lamp (CHMSL), through the BCM. The stop lamps are grounded at G401 and G403.
Do you know where the BCM is located ? If it should come down to it that the BCM needs to be replaced , It has to be programmed an the dealer is your best bet !
Replace the BCM. Refer to Control Module References for replacement, setup, and programming.
There is no relay ! !
Do you know where the BCM is located

can't find exact location for you but here is a link to a caddy forum , someone there will know
1990 Deville BCM ECM communications problems Cadillac Forum Enthusiast...

your BCM is located below the right side of the Instrument Panel. there should be 1 or 2 9/32 screws hold the brack. Disconnect all connectors and slide out BCM. Note the replacement BCm well have to be programmed.

The BCM should be located underneath the center console towards the front underneath the dashboard! You can also check with Advance, O'Reilly or Autozone salesperson and they should be able to print you up a diagram for your year and model to use as a reference. I hope this helps you!

Diagnosis by parts replacement is getting a little frustrating and expensive is it? Did you bother to scan the BCM for fault codes before replacing it? Have you scanned your new BCM for fault codes?
Have you verified proper operation of the Inadvertent Power Relay? Have you verified proper operation of the courtessy lamp relay? Have you checked to see if the BCM can command the courtessy lamp relay on? Is the BCM recieving power from the Inadvertent Power relay? Are your courtessy lamps recieving power from the Inadvertent Power relay? Is the courtessy lamp relay providing a good ground for your interior lights?...These are just SOME of the possibilities - that is what DIAGNOSIS is for...

Please also read the following article:
What Else Could Be Wrong?

you are having problem with the body controll module(BCM) need to replace.