Fwiw the automatic change to fresh air is to mitigate CO concerns, not mold. Mostly because of the police interceptor issue but other vehicles with vertical tailgates also had intermittent co intrusion due to a hatch or door ajar or a damaged gasket.

Have you installed a cabin air filter? I think most transits don’t come with them? But they have a spot for it.

 

The following pictures are from a 2019 factory wiring book. You might try unplugging the connector and probing with a DVM,

 

Maybe a DPDT Switch? so you can make the default mode recirculate if you want.

 

Something dead simple to try:

Make sure the actuator door is where you want it. Unplug the connector. See what happens.

Worst case is that you get a code set and you need to plug it back in and reset it.

I didn't look carefully at the schematic, but it there are some wires you want connected and others you don't, then carefully remove them from the connector shell and tape them up.

There are lots of more complex things to try if that doesn't do it for you.

 

This is what I found. If you close the recirculate door with the recirculate button, then unplug the connector to the motor for the door, the door stays closed. When I reconnected the motor the door refused to respond to the recirculate button, the light for the recirculate button responded but the door did not respond. put in defrost mode door did not respond. (stays closed). If you cycle the ignition (off-on) the recirculate mode goes back to normal. The connector C289 is to the left of the cabin air filter back in about 4 inchs. You can see the door if you look from the engine side of the air intake, or if you pull the cabin air filter. also No money light. this is on a 2019, YMMV

 

If circuit CB123 (Fuse 23) is interrupted. The HVAC control module will reboot back to normal mode, no need to cycle ignition. Use 2 switches one switch for circuit CH208 or CH207 to freeze to door position and one switch for circuit CB123 to reboot the HVAC control module. remember once in freeze mode the Recirculate button will indicate (light) that its working or not (no light) but the door will remain in the position that it was in when the circuit was interrupted. The door position can be seen be shining a torch in the engine side HVAC air intake.

 

Here's a foolproof solution, no guessing or wiring.

#1 Disconnect and remove the door inlet actuator
#2 Mount manual choke control cable handle through dash at chosen location
#3 Connect manual choke cable to inlet door

If you wanna get fancy, install a sensor to light up LEDs telling you if the door is closed or open, but the handle position should be indicator enough. You can hook it up to be either IN or OUT for when the door is closed.

Paypal is fine. IM for account.

 

The wiring access is easy, the door motor connection is to the left of the cabin filter, to access the HVAC module connection its behind the knobs for the HVAC, pop the panel and bobs your uncle, a one beer job.

 

 

Buy them books, send them to school, all they do is eat the pages.

 

I am interested in this. I don't know why people don't use re-circ more often. Especially without a cabin filter.

 

Could also be handy when is very cold, to maximize heat output. I have noticed that when its very cold that heat output is a little lacking when its not in recirculate mode.

 

On the early model Transit's you could not turn recirculate Off and everybody complained about that, There are a lot of old forum threads about it.

 

I have a 2019 first gen. (US) the default position for recirculate is off, door open. If you have it in recirculate mode on when you shut the van down, the door will remain closed. but when you restart, the door will open (recirculate mode off) you can hear it move when you turn the key to the on position