Upgrade Body Control Module on My Chevy Venture

I replaced/upgraded the Body Control Module (BCM) in my Chevy Venture after reading some information in my Owner's Manual about the ability to program the "Lock/Unlock Confirmation" if you have the right components installed in the van.  The key component was the BCM itself, but there is a little more to it.

I have done a couple of other "upgrades" to the van, like upgrading the Overhead Console & installing the Ambient Temperature Sensor, so this didn't seem to be a very big deal. The fact that I know a little bit about electronics and controllers doesn't hurt either ;).

Some background information:
My van came with what is called "BCM Version 3", which does everything that version 4 does EXCEPT - anything having to do with what is called the "Theft Deterrent" system.  This is the part that makes up the alarm, but also includes the "feature" that will flash the lights and beep the horn to confirm that the van is locked (or unlocked).

While researching this project (using the factory service manual), I discovered that the "option" for these cool features has a name (number really).  It is called "RPO UA6" and includes the following elements:

  • BCM Version 4 (see picture below)

  • Security LED (in the middle of the dashboard)

  • Some cabling between the BCM and the DRL (Daylight Running Light) module, Horn, Instrument Panel, and Security LED.

Since I didn't have any of these parts, I did a search on eBay for the Version 4 of the BCM (GM Part #10439803. BCM-3 is #10427831). I found a "Buy-it-Now" BCM for about $33.00, including shipping & handling.  This was the only "active" component of the upgrade, but I had more work to do.

Research & Construction:
While I was waiting for the controller to arrive, I poked around my van and found that the cabling I mentioned above was obviously missing.  Several connector pins in the BCM & DRL modules were not installed.  These are the lines that carry the signals that control the flashing of the lights and the beeping of the horn.  So I would have to make some cables to make this upgrade work.

The hardest part of building these cables was the fact that the van is "too new" to be able to find replacement parts at the local salvage yards.  My plan was to find the same type connector as the DRL module and remove a couple of pins that could be inserted into the current connector.  After visiting a few yards with no joy, I decided to go to my trusted parts house and see what they could do for me. After about 30-40 minutes, my "expert" at the part house found what looked to be the correct connector pin that would do the job (Thanks Jim!).  I did not have to worry about the BCM pins because the replacement came with its connectors still attached and the wires cut to about 4 inches. 

Making the cables was not that hard.  For the signal that makes the lights flash, I simply attached the new pin to the end of some wiring I had, so that I could insert it into the DRL connector in the right spot.  For the signal that beeps the horn, I found the wire at the bottom of the steering column and spliced into it with another wire.  That took care of the driver's side of the wiring.  For the BCM, I removed some pins that came with the new BCM connector and soldered them to the other end of the new cable. To keep it "easy", I tucked the new cable under the edge of the carpeting near the floorboard.

The next challenge was getting the new pin into the old DRL connector.  It probably would have been easier if I had everything on a bench and plenty of space to work, but I was working in the tight space below the steering column.  After what seemed like hours (probably about 30 minutes really), I was able to get the new pin into the connector.  Getting the pins into the BCM connector was a breeze, by comparison.

Once all the pins were in the correct connectors, I plugged everything back in and gave it a test.  Success!  All that was left to do was to clean up my mess and program the system to behave the way I wanted it to. The mode I picked (mode 4) was to have the lights flash any time the lock or unlock button is pushed on the remote, and the horn to beep when the lock button is pushed a second time within 5 seconds.

As a bonus, I noticed that the "Panic" button on the remotes I got from eBay now work!  Push it once and the lights flash while the horn beeps like crazy.  Push the button again and it stops.  Another interesting thing is that the "Trunk Release" button on the remote caused the lights to flash! (the eBay remotes were not an exact match to the van). 

Here are some pictures I took while doing the job.

BCM-4 Part # 10439803

Here is the Body Control Module (Version 4).
Notice the part number at the top of the label. 

BCM Location

Here is where the BCM can be found (passenger side).  In this picture it is hanging down by the connectors.  I had to remove the lower insulator panel and the glove compartment to have "easy" access to it. 

DRL Connectors & Location

Here is the DRL module can be found (driver side).  In this picture it is hanging down by the connectors.  I had to remove the lower insulator panel and another panel to get "easy" access to it. 
The white wire you see in the blue connector is the one I added.  This is Connector 1 - Pin "D" (see schematic here)

Important Note:
The connection between the BCM and the DRL only applies to 2001 (and possibly above) GM Minivans.  I discovered that the 2000 models have a theft deterrent relay that control flashing the parking lights, and not the DRL module.

Horn Wire Splice

This is where I spliced into the horn control circuit.  I did a "T-Splice" to the black wire. This connector is found near the base of the steering column and to the left side.  
The gray wire you see coming out the top of the black tape is the one I added.  It then runs under the edge of the carpet to the passenger side of the van and the BCM.

New BCM Wires

Here are the connector pins & wires that I removed from the new BCM connector and soldered to the end of the gray & white wires that come from the driver side of the van. 

The left picture below shows them inserted into BCM connector.
The right picture shows the module mounted where it should be

New BCM Wires

BCM Installed

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