Cab rear vent
I have an '06 450 extended cab 6.0 liter diesel. When a/c is on low or normal, the rear cab vents allow cold air to pass through the rear seat and exhausts outside the rear cab and cab never cools off.. It doesn't do that on MAX. Can I tape those vents closed or close them with tape and not have an carbon dioxide issue?
No. Beginning in 1973 vehicles are required to have fresh air moving through them at all times for the reason you mentioned. Exhaust gas build up in the passenger compartment under certain conditions. On MAX setting 80% of passenger compartment air is recirculated and 20% is pulled in from outside. On all other climate control settings 100% of the air is pulled in from the outside. If your rear seat passengers are uncomfortable you can safely keep the system on MAX. It won't hurt anything and you'll be safe too. HTH. -Jim
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