Halfway through the cycle the unit starts to squeal.
With the unit squealing halfway through the cycle you will want to check to make sure that there is nothing caught in the wash impeller or the drain impeller.
My dishwasher is not draining. I pulled it out from under counter and tested drain pump. I put my volt meter on orange wire terminal and white wire terminal going to transformer of drain pump. Should I have power going to these terminals as soon as cycle starts? How much ? and if not what next?
The drain pump would not turn on at the beginning of the cycle and when it does turn on it should have 120 vac getting to it. If the drain pump is getting power but not draining then you would want to check the drain to make sure that there is nothing in it causing the impeller not to turn. If it is clear but still not running with power applied then replace the drain pump.