2000 S430 Climate Control Problem
07-08-2014, 08:29 AM
#53
MBWorld Fanatic!
First - It isn't "Reset", it is for the residual heat feature. In cold weather, if you are making a reasonably short stop for lunch, shopping, etc., you push that button just before getting out of the car. A small pump circulates the warm coolant thru the heater, the blower operates on low speed, and the car stays warm...
Go to the top of the Forum page and find the "sticky" Encyclopedia where it says "Start Here". That is a collection of very useful info. Drill down thru the pages to find the detailed info on the HVAC diagnostic menu.
Go to the top of the Forum page and find the "sticky" Encyclopedia where it says "Start Here". That is a collection of very useful info. Drill down thru the pages to find the detailed info on the HVAC diagnostic menu.
07-08-2014, 02:39 PM
#54
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thanks Wally...my button says REST. I did read the stickys...after getting my system in AC diag mode..who knows what.. I have an ambitious mechanic, that keeps trying to get my car in the shop...to "take a look" but um..I dont think so..I have printed out the code list but the code I have isn't listed. the AC works and all, I know there is Freon, I watched as this was added, but the system just simply continues to produce hot air. Is there some thing I'm missing. I refuse to let this mechanic charge me $350 for something I can do myself? any suggestions or guidance is appreciated.
01-02-2015, 01:27 PM
#56
Junior Member
Thread Starter
Since your blower has to work for A/C, I am assuming that it is still working, but the air is not cool.
If that is true, then two basic things have to happen for you to get heat. Water that flows through your radiator and the head (where it gets heated) of the engine has to be circulated through your heater core (think of it as a small radiator inside your dash that has the hot water flowing through it), and your ventilation system needs to work to route the flow of air such that it flows through this heater core.
If you turn on your A/C, and put the temperature to low (to make sure the compressor will turn on), then switch to Heat you should be able to notice the cool air that is coming from your A/C evaporator go away because it should be flowing by the Heater core instead. The air can still be "cool" if the ventilation system is working, but it will not be cold. The other thing you may look for is to notice that the air is redistributed from the dash vents (that are above) to the floor vents. Heat rises, so heat is displaced from below. Cool air wants to go to the floor, so it is displaced in the dash vents.
So assuming that the ventilation is working, then the problem is that you don't have hot water flowing through your heater core. A couple of things can cause that.
1.) There is a valve that has to open for the water to flow through your heater core from the head. If it isn't opening, then water won't flow through it.
I would place bets again this isn't your problem.
2.) On some cars, there is something called an "auxiliary water pump". The sole purpose of this pump is to make sure water flows through this heater core when the heat is on. If it isn't working, then you may get air that changes temperature depending on what you are doing driving down the road. At a stop vs. driving fast, but it wont' stay warm.
I would place bets this is your problem!
3.) If your thermostat is stuck open, then in the winter the water never gets warmed up enough for heat. That is because the water in the head that normally gets heated up to around 192 degrees (or whatever your thermostat is rated at), stays cool. This thermostat opens and closes all the time and controls the temperature of the engine by doing so.
If the thermostat is stuck open, then water always flows through the radiator through the head and back out again, never getting hot enough for heat. If you are sitting still, then you may be able to feel some warmth. But the second you head down the road on a cold day, the cool air will cool the radiator, cooling the water that flows through the heater core and cool air will flow again.
I would place bets it is not your thermostat, or you would have noticed your temperature gage never gets to the middle or where it normally is.
4.) Water isn't circulating because you are low on anti-freeze. This can happen because while there is enough water still in the system to regulate your engine temperature (thus your temperature gage shows normal), there isn't enough for the hoses that connect from your head to the heater core and back to be full. The gaps of water create air pockets.
The most interesting thing about this is while you may see your temperature gage bounce from fully red to normal when this happens, the air temperature of the air blowing will be cool. The reason is the sensor for measuring the temperature of the engine gets exposed to these air pockets as well. But this air is actually "steam" now, and the temperature of the steam in the flow of air is hotter than normal. that causes your temperature to max out. But what actually creates the heat for you is the water flowing through your heater core and as air flows by, it is warmed up or 'exchanged". But we all know how much quicker a liquid can heat up something than air can. So even though the steam is hotter, the water at a lower temperature actually heats up the air flowing through the heater core much quicker.
I don't think this is your problem, or you would have seen odd things going on. Initially, you won' t notice your engine running abnormally. But then the absence of hot air will show up, and then pockets of air create in flow of water through the heater core, temperature gage bounces around. Eventually, your engine will over heat because this whole problem only happens if the water pump quit circulating water, or there is a leak somewhere.
In summary. I would place bets that you have a bad auxiliary water pump.
If that is true, then two basic things have to happen for you to get heat. Water that flows through your radiator and the head (where it gets heated) of the engine has to be circulated through your heater core (think of it as a small radiator inside your dash that has the hot water flowing through it), and your ventilation system needs to work to route the flow of air such that it flows through this heater core.
If you turn on your A/C, and put the temperature to low (to make sure the compressor will turn on), then switch to Heat you should be able to notice the cool air that is coming from your A/C evaporator go away because it should be flowing by the Heater core instead. The air can still be "cool" if the ventilation system is working, but it will not be cold. The other thing you may look for is to notice that the air is redistributed from the dash vents (that are above) to the floor vents. Heat rises, so heat is displaced from below. Cool air wants to go to the floor, so it is displaced in the dash vents.
So assuming that the ventilation is working, then the problem is that you don't have hot water flowing through your heater core. A couple of things can cause that.
1.) There is a valve that has to open for the water to flow through your heater core from the head. If it isn't opening, then water won't flow through it.
I would place bets again this isn't your problem.
2.) On some cars, there is something called an "auxiliary water pump". The sole purpose of this pump is to make sure water flows through this heater core when the heat is on. If it isn't working, then you may get air that changes temperature depending on what you are doing driving down the road. At a stop vs. driving fast, but it wont' stay warm.
I would place bets this is your problem!
3.) If your thermostat is stuck open, then in the winter the water never gets warmed up enough for heat. That is because the water in the head that normally gets heated up to around 192 degrees (or whatever your thermostat is rated at), stays cool. This thermostat opens and closes all the time and controls the temperature of the engine by doing so.
If the thermostat is stuck open, then water always flows through the radiator through the head and back out again, never getting hot enough for heat. If you are sitting still, then you may be able to feel some warmth. But the second you head down the road on a cold day, the cool air will cool the radiator, cooling the water that flows through the heater core and cool air will flow again.
I would place bets it is not your thermostat, or you would have noticed your temperature gage never gets to the middle or where it normally is.
4.) Water isn't circulating because you are low on anti-freeze. This can happen because while there is enough water still in the system to regulate your engine temperature (thus your temperature gage shows normal), there isn't enough for the hoses that connect from your head to the heater core and back to be full. The gaps of water create air pockets.
The most interesting thing about this is while you may see your temperature gage bounce from fully red to normal when this happens, the air temperature of the air blowing will be cool. The reason is the sensor for measuring the temperature of the engine gets exposed to these air pockets as well. But this air is actually "steam" now, and the temperature of the steam in the flow of air is hotter than normal. that causes your temperature to max out. But what actually creates the heat for you is the water flowing through your heater core and as air flows by, it is warmed up or 'exchanged". But we all know how much quicker a liquid can heat up something than air can. So even though the steam is hotter, the water at a lower temperature actually heats up the air flowing through the heater core much quicker.
I don't think this is your problem, or you would have seen odd things going on. Initially, you won' t notice your engine running abnormally. But then the absence of hot air will show up, and then pockets of air create in flow of water through the heater core, temperature gage bounces around. Eventually, your engine will over heat because this whole problem only happens if the water pump quit circulating water, or there is a leak somewhere.
In summary. I would place bets that you have a bad auxiliary water pump.
03-29-2016, 07:04 PM
#59
Junior Member
CLK430 Climate Problems
post 20 and 21 caught my eye...
dcsimmons or anyone who could help, please provide input...
The climate control unit no longer works and I'm not sure why there's heat coming from the defrost vents. What could be causing this?
I just purchased a set of removal tools but I'm having a hard time trying to get them to work....
dcsimmons or anyone who could help, please provide input...
The climate control unit no longer works and I'm not sure why there's heat coming from the defrost vents. What could be causing this?
I just purchased a set of removal tools but I'm having a hard time trying to get them to work....
03-29-2016, 07:28 PM
#60
Junior Member
Thread Starter
It has been a long time since I have had my S430, but the the problem you are having is pretty easy to identify. There is a 98% chance your problem is the heater control valve in the engine compartment. It regulates the water flowing through the heater core and will make your climate control totally worthless. If it is stuck open, then the impression will be the climate control has quit working when everything is still working correctly. The valve stuck open circulate all the hot water through the heater core. The temperature is usually controlled by this valve opening and closing in very small discrete increments, but it is probably stuck in a position now. Tapping on it with the A/C set to as cool as can be will usually break it open temporarily.
What is probably happening with the defroster vents is the system is sensing humidity, and the normal way to get rid of humidity in the car is for the climate control to click on the A/C compressor so the evaporator core can remove it from the cabin. But in your case, I believe the heater control valve is stuck most likely open, and so even though the A/C may be on, the heat is so much greater than the A/C that you are getting heat instead out the vents.
I would start there. If you had heat coming out of one side vent, and cold air out of the other, then we would start looking at the actual climate control and dampers because we would then know you have heat and cooling present in the system, and it was just being distributed wrong.
Hope this helps you out.
What is probably happening with the defroster vents is the system is sensing humidity, and the normal way to get rid of humidity in the car is for the climate control to click on the A/C compressor so the evaporator core can remove it from the cabin. But in your case, I believe the heater control valve is stuck most likely open, and so even though the A/C may be on, the heat is so much greater than the A/C that you are getting heat instead out the vents.
I would start there. If you had heat coming out of one side vent, and cold air out of the other, then we would start looking at the actual climate control and dampers because we would then know you have heat and cooling present in the system, and it was just being distributed wrong.
Hope this helps you out.
03-29-2016, 08:07 PM
#61
Junior Member
Thanks for that response..
Will replacing the climate control unit fix this, because the one I have has stopped working all together?
Will replacing the climate control unit fix this, because the one I have has stopped working all together?
03-29-2016, 08:09 PM
#62
Junior Member
Thread Starter
By all together, can you be more precise in what you mean? Does it still light u? Does the blower attenuate at all when you move the dial for temperature? Does defrost work, anything? Do you hear your compressor engage when you turn on the A/C?
03-29-2016, 08:19 PM
#65
Junior Member
Thread Starter
Are there any other items not working on the car? I am sure you eliminated a blown fuse as an option. in your case, it very well may be the climate control unit itself though. Sorry I don't have any other ideas. I haven't had the car for a long time and can't remember exactly how it works with the S430
04-03-2022, 04:17 PM
#67
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2001 s500
