I have a 2000 Windsor with the grid heaters and live in WY. I've had it for 10 yrs and the "Wait to start" light has never come on, but I've never had any trouble starting it until last year and now no matter what the temperature is, cold or hot it it spits and sputters and completely engulfs the coach in white smoke. So I'm interested in this subject. I haven't taken the time to figure out why the grid heaters aren't working.
The ambient air sensor on my truck "Cummins ISX" just hangs on the harness, but it is a 2010. Also a Barometric pressure sensor senses your barometric pressure (altitude)and keeps your engine running right whether you are at sea level or the top of a mountain.. That last picture you posted Bill looks like a barometric pressure sensor. There should be a part number on it if you can get it out. I know with my trucks , if you take it to the shop, they don't bother to test them, (all sensors) they just tell you to change them out. Easy for them to say that when it's not their $250. You could probably check continuity of your wires to the relay to see if that's the right sensor.