Failed Digital Heater Control Valve May Cause Poor Heat Output on Mercedes-Benz E320

Problem Description and Possible Solution

A failed digital heater control valve can cause a lack of heat output from the climate control system.

Problem Data
RepairPal Verified
Average mileage: 72,250 (40,000–91,000)
3 model years affected: 2003, 2004, 2005
15 people reported this problem
Viewing 1 - 7 of 7 comments
This is a small cheap part that costs about $100 to replace. Try this - under the hood, on the left side of the vehicle (as you look forwards) there's a plastic cover over the bulkhead behind the brake reservoir. Give it a healthy slap. Try your heater.
Climate control blows cold air only no hot air
My heater is blowing no heat just cool air...
Cool Air but no hot air coming out.
heater does not blow hot air only cold air
had to change control system entirely.