A couple of footnotes to the above video just in case anyone is looking into their own TrailBlazer TCCM.
[1] Our TrailBlazer etc. TCCMs do not click. They are solid state without mechanical relays that click. So don't be thinking your GMT360/370 TCCM is bad because you don't hear any clicking.
[2] Our TCCMs also will not output any voltage to the shift motor unless there is a shift in progress. No 5 volts, no nothing!
As far as his equipment, a nice fancy scantool and a nice breakout box,,,, I am too cheap! I guess I am more of a frugal, seat-of-the-pants, wing-it type!
Here is one of my test beds with a 2005 P10 PCM and a TCCM along with an assortment of bluetooth dongles, Arduinos, etc. This morning I was playing with instructions sent via phone, Veepeak OBD2 dongle and a serial terminal app.
At the far right just to the right of the test meter is a #194 bulb connected to the shift motor BRAKE circuit which I have activated by sending a serial data message.
Sitting on the test meter is another #194 connected to the shift MOTOR circuit. I have sent an instruction for a low power PWM signal so you can see the light is visibly weaker than the full powered brake circuit test light to the right.
The test meter itself is reading the same circuit as the light resting on the meter which is the actual shift motor circuits "A" and "B". We are seeing a 2.78 volt reading but remember this is a PWM signal so a reading from a DMM doesn't mean a whole lot. It DOES vary with the level of PWM I ask the TCCM to send it though.
At the base of the test meter is a blue and black 10-turn linear potentiometer that I have connected in place of the shift motor position sensor (encoder) to provide a signal to the TCCM. I can display that encoder reading in a serial terminal, Torque Pro or equivalent app using custom PIDs I developed.
Just left of those items is the 4WD mode switch which is partially connected to the TCCM. I skipped the indicator light circuits as I don't need them. The mode switch doesn't really do anything here but I can verify my PID readings from the TCCM for it's position.
Moving left is one of my phones connected to an Arduino and is displaying the current class 2 serial data messages from the TCCM and the PCM. This same serial data can be displayed using a Bluetooth dongle but here I am using my Arduino.
Speaking of Arduino that is seen inside the drawer to the left of the small cardboard box. I used hair ties to secure it to a 3-way OBD2 splitter in which can be seen 2 Veepeak Mini Bluetooth OBD2 adapters. When in a vehicle I use an extension cable to the 3-way splitter.
In the cardboard box is the 2005 P10 PCM with its' four 12 volt inputs connected along with grounds and serial data.
Just below the boxed PCM in the picture is a TCCM, the #12580060 unit with OS #12580062 and the #12581142 calibration.
Moving to the right end of the drawer is a few more stored items,,, Arduinos, Bluetooth OBD2 dongles, another TCCM. And above that is a Duracell 12 volt jump pack.
I have another setup in the shop but it's cold out there! That has another PCM, a BCM, Cluster, TCCM and sometimes items like a DDM, a PDM, Radio.... Etc.
