A/C Issues - Taking long time to work
Thread Starter
Newbie
Joined: Sep 2014
Posts: 3
Likes: 0
From: San Antonio, TX
09 C300
A/C Issues - Taking long time to work
I have an 09 C300 that is giving me A/C issues. I've checked Freon pressure and it is fine. What is happening is that my A/C does not come on most of the times until about 10 - 15 min after engine has been running. Once it comes on, it cools just fine. One way I know that it is not going to work is when the engine cooling fans don't come on full blast. I can get it to work sometime by starting/stopping/re-starting engine (sometime having to this several times). When the A/C starts working again, it smells really bad (like a wet damp smell). My cabin filter has not been replaced in a year so I ordered one to replace. Could this be the cause? This car has so many sensors that I'm thinking one of them is not working correctly. Thx, -Ariel
Junior Member
Joined: Feb 2014
Posts: 29
Likes: 1
From: Clermont, Fl
2012 C250
Similar issue, but not any where near 10-15 mins. Usually like 2-3 mins. But very HOT air, almost like the heat is on. Same fan situation. When the fans turn on (you know it, they're loud enough) the a/c blows cold air instantly. In central Fla., any amt of time w/out air seems like an eternity! I heard there may be a relay module of some sort that is to blame. Any more info would be appreciated.
Thread Starter
Newbie
Joined: Sep 2014
Posts: 3
Likes: 0
From: San Antonio, TX
09 C300
Yep, it gets hot up here as well 
. I can't say for sure if it really is 10 - 15 min but since it's my wifes car and she has to drive it, her yelling at me that it is blowing hot air feels like 15 min. I'm so disappointed in her C300 though. So many little things going wrong with it. Really sucks that warranty just expired like 3 months ago. I've already had to fix the Command Knob with steps from YouTube, vents in center dash are both broken and can't be adjusted, broken drivers headrest, front strut knocking on bumps, and list goes on.
. I can't say for sure if it really is 10 - 15 min but since it's my wifes car and she has to drive it, her yelling at me that it is blowing hot air feels like 15 min. I'm so disappointed in her C300 though. So many little things going wrong with it. Really sucks that warranty just expired like 3 months ago. I've already had to fix the Command Knob with steps from YouTube, vents in center dash are both broken and can't be adjusted, broken drivers headrest, front strut knocking on bumps, and list goes on.
Last edited by Ariel69; Sep 9, 2014 at 10:54 AM.
Junior Member
Joined: Feb 2013
Posts: 36
Likes: 1
From: Perth Australia
2012 C250
Junior Member
Joined: Feb 2014
Posts: 29
Likes: 1
From: Clermont, Fl
2012 C250
There is no way it's the design. If the vehicle sits for hours and the temperature is over 90 or so, then taa-daa no a/c. If it's either not 90 or sitting all day, no problems. If it was a design, then every morning when I went to my car that should happen. Or just every time in general. But unless certain criteria is met it works great.
Junior Member
Joined: Feb 2013
Posts: 36
Likes: 1
From: Perth Australia
2012 C250
There is no way it's the design. If the vehicle sits for hours and the temperature is over 90 or so, then taa-daa no a/c. If it's either not 90 or sitting all day, no problems. If it was a design, then every morning when I went to my car that should happen. Or just every time in general. But unless certain criteria is met it works great.
