Climate Control

I have and 99 E300 TD. Passenger side is blowing cold, driver side is blowing netrual temp. Where should I start?

Thanks.

Scott

__________________
1999 E300 DT 178k
1960 Ford Thunderbird Convertible 82k
2000 BMW R1200 CE 12k
2000 Nissan Xterra SE 145k
1994 Go Ped 1,000,000 miles

bump

__________________
1999 E300 DT 178k
1960 Ford Thunderbird Convertible 82k
2000 BMW R1200 CE 12k
2000 Nissan Xterra SE 145k
1994 Go Ped 1,000,000 miles

Start by checking the refriderant pressures, comparing to the chart in the climate-control diagonsitic manual. It's probably a low charge.