Originally Posted by silver-mod-o

put the truck in reverse, obviously with the parking brake on and/or truck in the air you rotate the switch until the reverse lights come on, then snug it up. It may not be the right way to do it I guess but its always worked for me.

if your wiring is not right all together though this may not work.

Originally Posted by Vince B

Outside of the EPC changing in 04 and the wiring harness change to accommodate this the manifold switch is still the same one its always been. Using the late or early set up is not an issue and I have personally done it in the past without an issue. Now I'm not sure if I read this correctly but did you say you have a bunch of fuses that do not have power? If this is the case I would correct this before doing anything else. Find out where the power supply comes from and figure out why its not completing these circuits.

Originally Posted by lady3bglover

I thought there's only one way that plug can go in b/c of the pins, and I'm assuming you're talking about the 7-pin and not the 4-pin.

Originally Posted by chris092183

I'm just not getting why there are 2 options for the mps. I'd just like to know why this is option is available. Maybe it's just the parts distributors that have it isted wrong bcause we all know that that is an option even though I found numerous suppliers with the 2 options available.

Originally Posted by chris092183

The TCM and the ECM are good and communicating with each other. I don't know if there is a High Speed GMLAN but I do think there are 2 tan wires at the connector so maybe they are apart of 2500 and 2501? I don't know. I'm thinking maybe any wire shorted out to the body can short out the bcm but then again I don't understand electronics and i'm slightly delirious being it's past 3:00am so

I id stumble across this though:

2007 CHEVROLET SILVERADO RECALL - #08V441000
RECALL FOR ELECTRICAL SYSTEM

GM IS RECALLING 857,735 MY 2006-2008 BUICK LUCERNE; CADILLAC DTS; HUMMER H2; MY 2007-2008 CADILLAC ESCALADE, ESCALADE ESV, ESCALADE EXT; CHEVROLET AVALANCHE, SILVERADO, SUBURBAN, TAHOE; GMC ACADIA, SIERRA, YUKON, YUKON XL, SATURN OUTLOOK; AND MY 2008 BUICK ENCLAVE VEHICLES EQUIPPED WITH A HEATED WIPER WASHER FLUID SYSTEM. A SHORT CIRCUIT ON THE PRINTED CIRCUIT BOARD FOR THE WASHER FLUID HEATER MAY OVERHEAT THE CONTROL-CIRCUIT GROUND WIRE.

as well as this

Body Control Modules and Ground Paths - GM Techlink

Body Control Modules and Ground Paths
By Blog Post on September 28, 2011 6:51 PM | No Comments
The Body Control Module (BCM) may be damaged if the module is supplied with battery power when the ground path is removed on some vehicles. The negative battery cable should be removed first before removing a BCM ground on 2006-2008 Monte Carlo; 2006-2011 Lucerne, DTS; 2006-2012 Impala; 2007-2009 SRX, Equinox, Torrent; 2007-2010 OUTLOOK; 2007-2012 Enclave, Acadia, Silverado, Sierra, Avalanche, Suburban, Tahoe, Yukon, Yukon XL, Escalade; 2008-2010 VUE, H2; 2008-2012 CTS, Express, Savana and Traverse models.

When the BCM is powered up (key in the Accessory or Run position) with the ground ring terminal removed or loose, the BCM will attempt to find a different ground path to the vehicle. This different ground path attempt may cause internal damage to the BCM.

The following systems controlled by the BCM may be inoperative or work intermittently because of an internally damaged BCM caused by a lifted BCM ground:

Interior lighting (will remain on or will not work)
Exterior lighting (will remain on or will not work)
Remote Keyless Entry
Door locks
Power windows and mirrors
Remote vehicle start
Remote trunk release


On 2007-2012 full-size pickups and utilities, the BCM can use two ground inputs. Both of these input pins (pins 1 and 5) are located on the X3 connector. The wires from these pins are tied to the same ground ring terminal in the vehicle. (Fig. 11)


The following is a specific list of vehicles and the components that the BCM ground wire passes through before going to the ground ring terminal.

TIP: Remove the negative battery cable if working one of these components.

Originally Posted by 1FastBrick

Hmmm Sounds familiar... Were have I heard that before... In all seriousness I hope you get this figured out soon. If you need help checking the GMLAN lines let me know.

Once you check all the wires and repair anything that may be damaged then most likely it will be the BCM.

For ever one else who has been reading this and offering help. I can read and comunicate with the ECM and TCM But the BCM will only show me the Module ID and software. I can not comunicate with the

Interior lighting
Exterior lighting
Remote Keyless Entry
Door locks
Power windows and mirrors
Horn.

I can how ever talk to the IP. I can sweep the gauges and turn all the warning lights on and off. The Radio works and the HVAC is all lit up.

I spoke with a Gm Master Tech and he said to make sure the GMLAN comunication wires were not shorted to ground. Once verifying all the wireing is good The most likely cause would be the BCM. It's not common but can happen. Especially liked mentioned above about connecting and disconnecting power from the Negative side. He said he could attempt to wake it up by tring to reprogram it and if that does not work then we would have to look into replaceing the module.

I was able to pull the TCM calibration but not the ECM calibration. I believe it is because of the active comunication fault code. I ordered an E38 Harness adapter for my bench top harness to see if I can pull the tune out of the ECM off the vehical. I am hopeing its just the communication fault code and not tunner locked. I would like to make sure we store and protect that info incase we have to go further then the BCM...

Originally Posted by chris092183

03regcab sierra: it seems as our problems may be different. My interior lights (dome lights) do not come on. This is really fun huh? well I hope I could be of help to you but I haven't go tmine running yet. I put a new battey in it as well. I knew it wouldn't fix the problem but my battery just went bad from sitting so long. Just for ****'s and giggles I tried to start it, but of course no crank, no start.

Originally Posted by chris092183

I did however find some relays that were put in the opposite direction so I am thinking my little brother did that. I haven't got it back together to see if the truck will start with the relays in the correct way, would that casuse my no start, no crank, loss of gmlan communication symptoms?