romansroad

Recently bought the CLK 350 for my daughter, and have already replaced the cam expansion plugs, fixed a few other odd items, will need to have the stealership address the 7 speed tranny issue (ugh!) and need your help on the climate control. Have searched for this, and no joy.

When one moves the either temp knob off the coolest setting, it immediately starts to blow hot air. Same for either knob, and when switched back to the lowest temp, it blows cool again. In effect, we have 2 settings.....hot and cold...no in between.

I did the recirc/defrost self check reset, and no joy. Poured over the EPC and can't quite figure out where the stuck flap/rod might be.

Kinda reminds me of our first MB, an early 90's Eclass that, when driven at altitude with open throttle, the vacuum would flip the vents in creative ways....

mis3

I had a defective flap 2 years old with my CLK320. The part was $20 but the labor was 5 hours. They had to remove the whole dash as well as the center console.

My experience was not the same as yours. Because of the defective flap, the air would come out only at the bottom. It happened on the driver side only so of course, I changed both sides.

romansroad

Glad to hear your was fixed...sorry about the 5 hours! I'm sure one of the experts here can tell me, as I'm not sure how this car controls the temp. Just glad we still have cool, since this is Texas and our winter is 15 minutes long

JDenhamCLK320

Where at in Texas

romansroad

We're in Dallas....usually use Park Place for the big work I can't/don't want to do. (If I only had a lift in the garage.....).

Have you had the Climate Control issue I'm having?

romansroad

I can't tell from the parts pdf's, but I assume the temp control engages a stepper motor on a hot water control valve along with a flap control to steer/mix AC with hot conlant air to yield the desired temp. Clearly, there are two of these in the dash somewhere, as it is a dual zone, but both not working is wierd, and implies a common part.

romansroad

I was hoping someone could share their knowledge of the system so I could repair it, or at least not get stung at the stealership.....anyone?

dwoody

We just purchased a 2006 CLK350 and have exactly the same problem. All cold or All hot. If either knob is turned off max cold (i.e.64F) we get hot air. Even it if is turned to 65F on either side. Have you found a solution? Thanks.

Glyn M Ruck

See the full W203 HVAC presentation in the Wiki ~ same for W209. It might be the cabin temperature sensors but unlikely as there are 2. One in the controller & one in the overhead console with sniffer fan. The unit takes the average of the two.

Most likely are the blender flaps playing up!

pennstate95

I have the EXACT same problem. When I did the reset, it appeared to fix the problem....but it didn't. I think it was because I was in the garage and it wasn't too hot out. If anyone finds the problem, please post. I'm trying to avoid taking it to the dealership and bending over for them. It's a lesson learned....to check the A/C when buying a used car. When I test drove it at the dealership, they must have known something because the sales guy set it to full blast LO (it was this past July when I bought the car). I hope it's not too expensive to fix.

Rudeney

Low refrigerant can cause odd problems. Our C240 was blowing hot air on the driver's side, but cool on the passenger. I put about 1/3 of a can of refrigerant in and it fixed it. I know that really doesn't make sense, but I have heard this same situation many times.

pennstate95

I had the freon checked by my mechanic and it is full. I've just been controlling the temperature with the fan. If it's hot, set the fan at full blast. When it cools down, I lower the fan until it blows enough to maintain the temperature I want. That's my redneck work around for now. =)

TechSuperstar

.... Well I just took my car in for a windshield replacement. Came out with a new windshield and this exact problem!!!!

I asked the glass people if there were any sensors maybe they forgot to hook up and they said nope, there is only the rain sensor and windshield heater. I'm thinking there is a sensor in the upper center box where the rain sensor is and maybe that is effecting the overall climate system. So now I also have the same problem (either full heat or full cool). What I don't understand is it still blows hot air even if i manually adjust it. Why would the climate control care what the cabin temp is if i'm manually setting the temp. Oh well.

Don't know what to do now.

TechSuperstar

I remember seeing a W209 chassis manual around here some time back. Does anyone have that link, i belive it showed where the climate sensors were.

Does anyone have any pics of whats inside that box in the center of the windshild? I know there is the rain sensor and i think light sensor, microphone for the phone and I'm assuming climate temp sensor. Is there something inside there that could have unplugged when removing the box from the windshield?

Patton001

This is what my mechanic told me https://mbworld.org/forums/clk-class...ml#post5642794

Glyn M Ruck

There is a HVAC sensor & sniffer fan in the overhead console that they must have disturbed or not plugged in.

Rudeney

There is no reason to remove the overhead console when replacing the windshield, but it is still possible they broke something - maybe a wire was hanging out of the trim close to the glass and they cut or disturbed it. The guys that replaced my glass used a cutting wire on this complex pulley system to cut the urethane to remove the old glass. They almost let this razor-sharp wire cut through the wiring harness to the (removed) mirror and rain/light sensor module but they realized it at the last second.

Glyn M Ruck

+1^

TechSuperstar

After diag's the local dealer said the temp sensor was reading 32degF ended up replacing the entire board. It was probably possible to fix since a thermocouple is just two wires put together but of course they're not about to do that. Total cost was almost $650.

I did however get a reimbursement from the glass company for the repairs.

Rudeney -- yes the center dome console must be removed when replacing the glass because the trim must be removed, for the trim to be removed first the dome must be removed. In addition, I actually saw the car being worked on with the trim and dome removed.

Rudeney

I watched (and helped) when the front windshield on my CLK550 was replaced and they did not remove the overhead console. They did remove the mirror, the electronics on the rain/light sensor, but not the overhead console.

TechSuperstar

Hmm that's odd. I guess different places do it differently. They put the top down to get at the bolts that hold the dome in place, took it off as well as the trim. They even took off the left and right side trim. Oh well.. in any case I was real glad they reimbursed me the money for the repairs.

Rudeney

When they replaced mine, the removed trim from both the inside and outside A pillars, the windshield wipers and the plastic trim behind them, the metal trim across the outer top of the windshield, and the rearview mirror along with the rain sensor module. They did not touch the overhead control panel or the interior trim at the top of the windshield. They used a winch system, suctioned to the glass, to pull a razor cable all the way around the glass to cut through the old urethane seal. They cam within one crank of cutting the wiring harness going to the mirror;/rain sensor, but luckily I caught that before it was too late.