Combines Cab fan in 1998 R52

Maybe what you need would be a surface mounted 12 volt fan to help circulate you cold air. I also understand there is no way to shut off bringing in outside air besides letting the upper outside cab air filter get dirty enough to restrict intake flow. The filter below the cab filters air from inside the cab, make sure it is clean and the system should recirculate the colder inside air. That's a good thing unless you cant stand yourself..... Good luck

Filter below cab floor is plugged--fan runs, but blows little or nothing. look in Op manual for location as it's hard to describe.

Pull the cover off under the cab and clean the evaporator and heater cores. A caked core will restrict the air flow.

If you have the time look in older posts below as to adding a relay for high speed. Fan switch pulls compressor and fan which lessens amps sent to blower. We add a relay to power the fan directly to the fused cab relay voltage on high. Adds volume, but clean the cores as above first.

the openings below the seat are cab air return openings. open or close to control outside air