automatic climate control

[BillKerler]

On a '94 C280, if the outside ambient temperature is 45 degrees F or lower, I do not get warm air out of the front side vents even if the engine is up to operating tempersture. The system waits for 5 minutes before the duo valves are allowed to let hot water flow by them.

Why? It's very frustrating on a cold day. I have to increase the cabin temperature setpoint control to Hi in order to get warm air through the vents. A Hi setting seems to force open the duo valves.

As soon as I lower the setpoint to 92 degrees F or lower, the 5 minute timer kicks in before the duo valves will reopen up.

Anyway to change this logic circuit? Does anybody else suffer with this problem?

46 degrees F or higher outside temp and this climate control works like a champ. It constantly alters cooler air in the center front vents and warmer air in the side vents for a pleasant overall cabin temperature based on whatever setpoint temp is dialed in.

[roundl]

I just replaced my cabin air filter in my 97 C280 Sport. It was probably the original and was filled with leaved, bugs, and dirt. My cabin now heats up very quickly.

[martattack]

Originally posted by BillKerler
On a '94 C280, if the outside ambient temperature is 45 degrees F or lower, I do not get warm air out of the front side vents even if the engine is up to operating tempersture. The system waits for 5 minutes before the duo valves are allowed to let hot water flow by them.

Why? It's very frustrating on a cold day. I have to increase the cabin temperature setpoint control to Hi in order to get warm air through the vents. A Hi setting seems to force open the duo valves.

As soon as I lower the setpoint to 92 degrees F or lower, the 5 minute timer kicks in before the duo valves will reopen up.

Anyway to change this logic circuit? Does anybody else suffer with this problem?

46 degrees F or higher outside temp and this climate control works like a champ. It constantly alters cooler air in the center front vents and warmer air in the side vents for a pleasant overall cabin temperature based on whatever setpoint temp is dialed in.

The car does wait a little bit for the heater core temp to raise before it starts blowing really hard, but it should still be pumping a little warm air into the cabin while it heats up. Like someone else said, check your cabin air filter. I replaced mine after I bought my car and it helped tremendously!

[BillKerler]

Thank you - I did replace my cabin filter before making this comment. The owners manual describes the 45 F delay period. The Haynes repair manual for the W202 is from England and the automatic climate control is not covered (just the good old trust worthy manual type). I only get the warm air quickly if outside temp is 46 F or higher.