I have a 92 S320 that the heater stopped working. I took apart the duo valve and found the problem but was not able to "repair" it. I made it so it is just HOT. Control the temp by off/on and fan speed.
But the more I look into this the more I become curious and since there is no manual for these beasts I was wondering if anyone could answer a question for me.
My duo/dual/heater valve has 5 hoses coming off of it. 1 goes in and 4 come out. Without completely dismantling the firewall and tracking these hoses, can someone tell me what the 4 out-going hoses go to?

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1987 350SDL Parts Car
1987 350SDL #2 Sons Car
1991 350SD My Car-RIP 9/7/09
1992 300SD Her Car
1995 E300 Spare Car-RIP 4/23/09
1992 S320 My Car - Soon to be diesel
1990 W250 4x4 Cummins #1 Son's Truck
1993 D350 Cummins My Truck
1999 3500 Cummins Just Another Truck
1987 Executive Cat 3208 Family Wagon

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