[earaim]

I own a 02, W163 with heater problems “82K”miles. It is running fine except heater started to blow cold air. I read threads about actuators not working correctly. The AC always works and gets cold. The heater on the other hand starts OK then blows cold air. I already check & replaced anti-freeze, replaced water pump & thermostat (3 hr job). I checked actuator motor behind glove box (working as planed). :surrender: What is my next step? Any good advice is greatly appreciated.

 

[timoparn]

I own a 02, W163 with heater problems “82K”miles. It is running fine except heater started to blow cold air. I read threads about actuators not working correctly. The AC always works and gets cold. The heater on the other hand starts OK then blows cold air. I already check & replaced anti-freeze, replaced water pump & thermostat (3 hr job). I checked actuator motor behind glove box (working as planed). :surrender: What is my next step? Any good advice is greatly appreciated.

Hi,

a bit more info please :

a) how did you checked the actuator motor? Holded your hand to motor and felt movement?
b) you can change the direction of air movement but it always blows cold? (floor, center vents etc)
c) when you move the dial to totally hot, you still get cold?
d) have to scanned the system with scanner? any faulty sensors?
e) Have you had low batter/ replaced batter at some point in near past?

all the best,
Timo

 

[earaim]

Thanks for your reply. answer below:

a) I read it from this forum. I took the glove box and observed the movement. It did not get stuck. There is also a youtube video about it.
these pics helped: http://www.benzworld.org/forums/w163-m-class/1474816-youre-all-gonna-think-i-lost.html

b) Yes, cold from any direction. It starts warm for 3 seconds then seems to bring in outside air shortly after. With the cold weather theses days it is no fun.

c) That's where I leave it. I tried the auto setting or the manual with same results.

d) I don't have a scanner is there someting you can advise me about? I do own a voltmeter.

e) I replaced my battery 6 months ago.

 

[Witek_M]

I own a 02, W163 with heater problems “82K”miles. It is running fine except heater started to blow cold air. I read threads about actuators not working correctly. The AC always works and gets cold. The heater on the other hand starts OK then blows cold air. I already check & replaced anti-freeze, replaced water pump & thermostat (3 hr job). I checked actuator motor behind glove box (working as planed). :surrender: What is my next step? Any good advice is greatly appreciated.

If blending flap motor moves to full heat position something may be broken inside heater box that keeps flaps from moving.

Or there is no coolant flow through heat exchanger. With engine at operating temperature and ACC off check temperature of return hose from heat exchanger. It needs to be close to engine temperature. Turn engine off and feel auxiliary water pump. Pump needs to hum and there should be visible coolant movement in expansion reservoir. Pump operates for 5 minutes after engine off. Or longer if you use REST.