Thanks to a forum member poking my brain offline, I'm pretty sure the timing mechanism is built into the recirc switch. It might be possible to replace the recirc switch with a simple toggle so it stays on as long as the switch is on as well right from start up. I don't know if the temp control unit will miss the other connections. If so, maybe you can leave the recirc switch behind the console and splice in a simple toggle that sits in the console. Anyone know if the traction control switch is a simple toggle like the rear dome light switch?

Sixto
95 S420
91 300SE
87 300SDL
83 300SD