Advise on CDL Class A airbrakes.

There is nothing for the electric side. You follow the Manual of Air Braking whatever is in your CDL Teaching book regarding airbrakes and apply it to as much as your tractor will tell you through the primary, secondary air and Mr Buttons as well as low air alarm and Mr Pop. As long you follow the test procedure for determining if the air leak is present and so on you should be good to go.

Even if there was a tractor trailer with full electric braking meaning no air at all.. (That's something I am not yet willing to accept...) you wont have any air brake endorsement with that particular full electric truck and trailer braking.

My post stands on what I know of (Some of which can use a little brushing up) of airbrakes in general, totally ignoring the presence of electric brakes in part or whole vehicle. If there is a Primary and Secondary air present in your tractor cab that is what you have to go by.

As far as the loss I usually take 4 PSI as a max allowed loss over one minute provided it does not lose any more. But my way may not be texas way at the test examiner standing over you at test time. This is with service brake only ignoring the trailer trolley valve for the test purposes.

 

As a former CDL examiner I would want to see you use the single vehicle rates, 2&3 PSI/minute, but also want you to tell me the combination vehicle rates 3&4 PSI/minute.

No, you would not push in the red trailer knob, you don't have a trailer attached. To properly check the electric trailer brakes in cab you would release your tractor brakes (yellow knob) then push and hold the manual activate button on the electric trailer brake controller, pull against the brakes gently to show they are holding, then continue with checking the tractor brakes.

Also, during the brake test with electric brakes you need to check the emergency breakaway switch, so you have an extra step of exiting the cab, pulling the breakaway switch then getting back in cab and gently pulling against the trailer to see that the breakaway (emergency) brake holds.

Be aware, you may get a partial air brake only restriction using this setup. Since 2015 it has been a requirement to test in a full air brake vehicle. Check with the exam site to see if this applies in Texas or if they only care about the tractor being full air brake.