My new mercedes A250 just started blowing hot air instead of cold from the air conditioner

SOURCE: '98 S-10 heater blowing cold air - not hot air

will the air flow switch from floor to the mid to defrost? if so then we have a problem with the tempature door actuator. easy to replace just in tight place. Keep me posted for more help or if this was any help thanks

Paul W

• 404 Answers
• Posted on Feb 24, 2009

SOURCE: Nissan Altima no cool air blowing or hot air blowing

Hi!
It appears we have an Air lock scenario and you will need to perform a system Bleed.
Park the vehicle on level ground, when cold remove coolant filler cap, start engine and leave to idle, turn heater on full and blower to max. When engine reaches operating temperature watch and listen near coolant filler, keep clear as gurgling and hopefully a boil over should occur. Top up with very warm coolant and wait as it may do it again.
Check for heat inside vehicle if warm replace coolant cap but keep an eye on temperature gauge as the ~Air lock may have moved on from heater matrix/core so proceedure needs to be carried out again from COLD.

Please press the Blue button to appraise my FREE Efforts, Thank You!
Paul 'W' U.K

SOURCE: air conditioner blows hot cold and sometimes not at all why?

hello,seem you need to send your car to authorized dealer to scan the problem,maybe the solution is only synchronizing all the flap,ty

SOURCE: air cond goes from cold to hot on coldest setting or if its on hot it will start blowing cold

You have a broken wire on the heater control potentiometer. You can either order and replace the control, which is expensive, or you can remove the control, and disassemble it, and re-solder the broken wire. We do this all of the time; resolder the pots bacjk on to the main PC board.

SOURCE: My air conditioner won't blow cold air. It just blows air.

Hello I'm a M.B. tech. 1st you need to know why the freon is low. Hopefully it just needs to be serviced. There is a component located in the lf of the engine compartment called a receiver drier. It soaks up the moisture in the freon so the gases can work the way they are supposed to. On this unit there should be 2 switches(I believe they were combined into one switch in 98. 1 switch is a temp switch that operates your electric fans, the other is a compressor cutoff switch. Assuming the compressor is not coming on-take a fused wire and bridge the 2 contacts- If the compressor does not come on at all there is another problem(it is not low on freon. On the condenser there is a high side port(it is the bigger of the 2)By the brake master Cyl.(lf of the engine compartment thereshould be a smaller low side valve in line with the fuel cooler hose. Usually you can hook up a machine to the low port and **** freon in through that port. Assuming you do not have a refrigerant machine. It is very self explanatory on the bottle of r 134a refrigerant which can be purchased at your local auto supply store. I would start with 1 lbs. and add dye with the freon in case there is a big leak. If the system is overcharged it will not cool properly. I believe the system capacity is approx. 2 lbs. Add a few ounces after the first pound until a/c system is cooling properly and the electric fans are also coming on when the system gets to high. If you get a can with a good Gage set on it you should see the high side between 150 and 2000 psi(fan coming on at max. press.) also the low side should read about 35. It is about the temp of the evaporator which is i=located in the dash and the blower blows through this component out through the vents. Hopefully I have been helpful.