Before you start, make sure the vehicle is in Park for automatic transmissions, or in gear with the parking break off for the ZF6 trucks. The vehicle must be turned off and it is recommended to disconnect both negative battery terminals using an 8mm wrench.
Next, you will find your Electro-Hydraulic Control Unit on the drivers side frame rail, my truck is 4 wheel drive, so right next to the transfer case.
I only replaced the EBCM, which is the computer on top of the EHCU. Make sure there is no loose dirt that could fall inside once the EBCM is removed. The two small connectors come loose simply by lifting the tab and pulling them out. The big connector has a red locking slide that must be moved down the connector before it will come loose.
Once the connectors are removed, undo the 4 T-20 torx head screws that hold the EBCM to the Brake Pressure Modulator Valve. Be prepared to drop your torx socket into the frame rail a few times, as the two rear screws are a little hard to get the socket into.
Next, Remove the EBCM from the BPMV, DO NOT use any tools to pry them apart, as you could damage the very expensive BPMV. Mine came apart by hand no problem, but you may have to use a little force.
Here is a comparison between the old part and the new
When installing your new EBCM, GM recommends using 4 new screws, however I reused the old ones. Your new EBCM comes with a new seal, DO NOT use any RTV Silicone or gasket sealant on this. The screws should be torqued to 39 in lbs, but I just guessed, then re install your connectors. No bleeding is required since I only replaced the EBCM, and GM also recommends calibrating your tire size with a tech 2, which I did not do and havn't seen any problems.
Please don't yell if I did something wrong, this is my first writeup on the forum and I hope you enjoy it!