ES330 AC Blower motor replacement failure

[TFL]

I replaced a noisy but functioning AC blower in an '05 ES330, with a new part.  I've not replaced any panels or the glove box yet.  After part swap, I attached plug to blower, and reconnected the battery.  Car starts as expected, and everything else works, but no function from the blower fan switch.  DIsplay does show increasing bars for blower speed.  I then disconnected plug from new part, and plugged in original noisy part, but no fan function with that part either.  I've not replaced any panels or the glove box yet, as I wanted to verify that blower was working before I reinstalled all the panels, etc.  Is there some interlock switch on a panel that is needed for the blower to function ? Or any other idea what my problem might be ?  Thanks for your thoughts

[gbhrps]

TFL,

I've replaced a pile of these on all makes of cars over the years, but never on a Toyota.

Question: are you missing a ground wire? By that I mean, did you fully install the fan motor back in its housing, or is it just sitting on the floorboards all hooked up? If its on the floor, then its possible that it finds its ground wire when fully installed.

If fully installed and still no go, either the fan resister or the switch itself is at fault ... I suspect. Test the switch terminals from ground through each setting or on its rheostat circle if that's the type you have. Trace the switch wiring to the fan resister and see if it has continuity on all settings (if there is one, since the switch rheostat may be the resister itself) and see if you have continuity with an ohm gauge.

It is possible that the switch circuit board has a bad/broken solder joint. Check the board carefully to see if it can be resoldered. Good Luck!

[TFL]

Gene, Thanks for the quick response.  Thankfully, it didn't get as complicated as the issues you described with the grounding wires.
But it did prompt me to re-check all the connecting plugs, and I found an sever instance of AMO - amateur mechanic oversight. 
Re-seated one of the plugs, and away we go. 
Thanks again.