Hot air comes from drivers side only for minute or two then stops

VIVEKHB

MEMBER
2003 MERCEDES BENZ C230
1.8L
4 CYL
2WD
AUTOMATIC
235,000 MILES

I noticed that actuator M2/15 and M2/6 rotate for 2-3 cycles and then stops, hence the hot air flow also stops on driver side vents but hot air continues to blow on the passenger side.
I confirmed this by repeating the procedure.
Please, your opinion will be highly appreciated. Thanks in advance.

Vivek

6 Replies

KASEKENNY

MECHANIC
18,907 POSTS

Just to confirm the issue so that we are on the same page, the driver side blows hot air when you have it set on cold? Or is it the passenger side that is blowing hot when set on cold?

It sounds like the actuator is the issue but I just want to be sure I understand the issue so that we are giving the best advice.

https://www.2carpros.com/articles/replace-blend-door-motor

Please review this material and let me know if I am not understanding the issue.

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Saturday, June 19th, 2021 AT 3:44 PM

VIVEKHB

MEMBER
89 POSTS

Sir, good evening. When the heater is turned "ON" only passenger side blows hot air.

1. I replaced the broken M2/15 actuator arm.
2. I changed the M2/6 actuator.
3.I then synchronized the M2/6 actuator by pressing the defrost and re-cir. Switch simultaneously.(It stopped fluctuating, lastly only defrost lamp stayed lit.)
4. I got hot air during the synchronizing process through all the vents, but, now no hot air from drivers side while passenger side I do get hot air.

I noticed that there is no movement of the M2/6 actuator lever.
Is it something to do with the synchronizing procedure. Your valuable advice will be highly appreciated.

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Saturday, June 19th, 2021 AT 8:47 PM

KASEKENNY

MECHANIC
18,907 POSTS

If the actuator is working when you run through the sync process then we can assume that the actuator and wiring is okay. This would leave a module issue.

However, we need to test the wiring just to make sure you are getting the 12volts that you are supposed too and then the signal wire should vary depending on the position and you can compare this with the passenger side that is working.

https://www.2carpros.com/articles/how-to-check-wiring

I attached the wiring diagram that will help with this.

Please run through this and if the voltage is the same on both blend doors then you need to replace the control module. Thanks

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