Air recirculate doesn't work with heater?

[KuiMonster]

So now that its starting to get cold the heater has been coming on. I keep the air recirculate on because i rather not smell all the exhaust fumes and weird smells from outside. But now all i can smell is the exhaust fumes from other vehicles even with the button on. Is this normal that it doesn't work with the heater on?

[redwngr]

Recirculate still runs a % of fresh air.

[KuiMonster]

8 hours ago, redwngr said:

Recirculate still runs a % of fresh air.

Correct, but does it let more fresh air in with the heater on? It seems like the recirculate doesn't work at all when the heater is on. I know my old truck (ford) would turn off the recirculate after a few minutes with the heater on and once i pressed the button again it would work. Im just wondering if this truck just lets more air in automatically without the option to stop the exhaust fumes from coming in.