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Replacement parts for Whirlpool KEYL517BWH2 ELECTRIC DRYER | AppliancePartsPros.com

See the attachment for the tech sheet.

Before I go back to the repairman, is there any way to check the new motor to make sure it's not defective?
You could bench test it but that involves making up a cheater cord and doing a live test. I would just check the motor windings with a meter, 5M to 4M should be about 1 to 2 ohms.

You could also do a full circuit test.
Be sure to short the meter leads together before starting so you know if the meter has a zero offset.
Unplug the unit.
Attach (tape etc.) one meter lead to the Neutral pin of the line cord and leave it there.
Check Neutral at the terminal strip, should be 0 ohms.
Door switch must be closed.
At T ( Timer Switch 4) at the timer, should be 0 ohms.
At W (Timer Switch 4), should be 0 ohms.
At 5M on the motor, should be 0 ohms.
At 4M on the motor, should be an ohm or so.
At both sides of the thermal fuse, should be an ohm or so.
At R2 on the Push to Start Relay, should be an ohm or so.
At R1 on the Push to Start Relay with the button pushed, should be an ohm or so.
At BU on the timer with Push to Start pushed, should be an ohm or so.
At BK on the timer with Push to Start pushed,should be an ohm or so
At L1 (black) on the terminal strip with Push to Start pushed,should be an ohm or so.
At the L1 pin on the power cord, with Push to Start pushed,should be an ohm or so.

There that is the complete start circuit for the motor.

I hope I have not screwed you up but looking at my original post I neglected to tell you to set the timer to a dry cycle mid point.
You want the unit in a state where pushing the start button will start the unit so it cannot be at Off.
Timed dry is better as it's circuit is simpler but it should also work for auto cycles.

If this is what you did then I would say that your timer is toast.
Timer Switch 4's contacts are not closing re: you should see the same resistance on both sides ( At T and at W) if it was closed.

Also the resistance at BU and BK should be the same again because the contacts should be closed.

If I did mess you up I apologize. It is just that this stuff becomes second nature after a while and you just do it without thinking. Sometimes I have my head up my you know what and forget it is not second nature to a lot of other people.

FYI: It is really not hard to understand. Print a copy of the wiring diagram and then take a colored pencil and trace the circuit by connecting the parts.
Now you can see how the motor gets power through a completed circuit path Neutral to L1 (live).
Any set of closed contacts is 0 ohms (no resistance) so you should see the same ohms readings on both sides if it is closed.