A/C trouble in 99 CLK
07-31-2006, 11:20 PM
#1
Senior Member
Thread Starter
A/C trouble in 99 CLK
Hello, everyone:
I have a 99 CLK 320 cabriolet with 25,000 miles on the clock. In the mornings when it's cool, the A/C blows frigid air, but in the afternoon, after the car has been parked in the sun, the A/C doesn't cool at all. If the A/C is shut off before the engine is turned off earlier in the day, there is a possibility it will cool once the windows have all been rolled down and the car has been driven a short distance (1/4 mi), but this is not always the case. If the A/C blows cold air once turned on, in about 3-5 minutes, it will begin to blow warm air, clearly as though the compressor had been shut off. The next time the car is used, if the interior has cooled off, the A/C goes back to working properly. I have tried to shut off the compressor with the EC button, but turning it back on does nothing. I have also tried shutting down the A/C, then shutting off the car and at times the A/C will work properly once the engine is back on. The only thing that seems to work, is to keep the fan on the 3rd or 4th bar, avoiding its maximal speed. Please give me some insight as to what the problem may be. I can put the top down on some days, but if it's raining, I suffer with heat and fogged up windows.
I have a 99 CLK 320 cabriolet with 25,000 miles on the clock. In the mornings when it's cool, the A/C blows frigid air, but in the afternoon, after the car has been parked in the sun, the A/C doesn't cool at all. If the A/C is shut off before the engine is turned off earlier in the day, there is a possibility it will cool once the windows have all been rolled down and the car has been driven a short distance (1/4 mi), but this is not always the case. If the A/C blows cold air once turned on, in about 3-5 minutes, it will begin to blow warm air, clearly as though the compressor had been shut off. The next time the car is used, if the interior has cooled off, the A/C goes back to working properly. I have tried to shut off the compressor with the EC button, but turning it back on does nothing. I have also tried shutting down the A/C, then shutting off the car and at times the A/C will work properly once the engine is back on. The only thing that seems to work, is to keep the fan on the 3rd or 4th bar, avoiding its maximal speed. Please give me some insight as to what the problem may be. I can put the top down on some days, but if it's raining, I suffer with heat and fogged up windows.
08-01-2006, 07:38 AM
#2
Next time you are in your car, with the engine on, hold down the rest button. When the first diagnostic value shows up, press the right "auto" button until you see the value for #5. This is your evaporator temperature sensor. If the temp is not within a reasonable value.....you have found your culprit.
P.S. While you're at it, you might want to check out value #7. This is your refrigerant pressure in bar. (Since you get cold air once in a while, I'm pretty sure you're ok there)
If it is the evap. temp sensor, it's an easy fix. About $65 from the dealer if I recall correctly and you can access it from underneath the driver footwell, along side the firewall. Good luck!
P.S. While you're at it, you might want to check out value #7. This is your refrigerant pressure in bar. (Since you get cold air once in a while, I'm pretty sure you're ok there)
If it is the evap. temp sensor, it's an easy fix. About $65 from the dealer if I recall correctly and you can access it from underneath the driver footwell, along side the firewall. Good luck!
