No heat

Could be a clogged heater core here is a guide to help you see what you are in for when changing the mode blend door actuator.

https://www.2carpros.com/articles/replace-blend-door-motor

and

https://www.2carpros.com/articles/car-heater-not-working

Check out the diagrams (Below)

Please let us know what you find. We are interested to see what it is.

Cheers

my problem is i have no heat or air working at all, seems as there is no power to the fan or temperature control unit. I remedied this by replace the blend door actuator thanks 2Carpros! I think the cost would be associated with this problem was $265.00.

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Heater problem
2003 Mercury Marquis V8 Two Wheel Drive Automatic 78k miles

my car has no heat or air whenever i select either have to use the vent selection to stay warm in the cold weather and the fan does not blow with heat or ac selection replaced blower motor but still doesnt work what solution at a dead end, thanks

There is a blower motor relay in the power center under the hood near the battery, try swapping it with anothe relay (wipers, A/C) to see if it will come on . If not need to get a test light and see if there is power at the blower motor resistor (right side of firewall near blower motor)

Heater problem
2003 Mercury Marquis V8 Two Wheel Drive Automatic 700054 miles

The air works. The blowers work. Hoses are fine. Theremastaut is fine

I can’t get the heat to work on my 2003 Mercury grand marquis and the dealer said it might be the BLUNT door but I can’t find anything about it in the book. The hoses are fine the thermostat is fine. It’s not leaking water or antifreeze. I am trying to fix it myself because of the money. Thank Trish

Trish:
With the engine warm, the hearter on high, make sure both heater core hoses are hot. If they are, I think they are refering to the blender door. It opens to allow heat to pass the heater core and warm the car.

Thank you; I will try that. Trish

let me know what you find.

Joe

I have a 2003 Grand Marquis that is blowing air but will not get hot. I've checked the thermostat, anti freeze, and fuses. From what I gather there is a blend door valve that is prone to going bad and is coincidentally expensive to replace. Where is it and can I force it manually without replacing it?

Check the heater control valve and the heater core-if okay then deal with the air blend door/vacuum and actuator

I took it to the dealer and they said the problem was the blower fan, well i replaced it nd it still doesnt work. ive checked all of the fuses ans i checked the relays. i figured out that the electrical current is not getting the the motor but i have no idea what to check next. wha would be the most likely problem be? thank you

Find the power wire to the blower motor and power it direct from the battery and see what happens -start here

do you have manual or automatic controls.

how do i hook the power wire up to the battey? what is th differanc between auomaic contrls and manual? im not sure what i have.

on auto you set temp # and it holds temp at that setting by auto manipulating other control factors.

on manual system, your blower is ALWAYS HOT with mode switch anywhere but off. so check blower for hot wire good 12v. your mode switch grounds blower relay(turns 12v on) and your blower switch grounds blower motor to make it run. relay is by battery in junction box.

Ok then I have auto.

I had this same thing happen to me. It was the blower motor control resistor. You probably do not want try to tackle this yourself. I watch the service tech who had every tool you can think of battle it for about an hour. There are some plastic clips that if you break them you have to replace the whole line. Only cost me 378.00 to get fixed at a/c shop and I was in the Florida Keys on vacation. So it's not worth risk.

Air Conditioning problem
2003 Mercury Marquis V8 Front Wheel Drive Automatic 92540 miles

my air and heater are not working , i can feel the cold air but it won't blow out same for my heater it just doesnt blow out , we connected the fan for the heater and the air conditioner directly to battery and it work , I am starting to think it my be the switch that turns the air and heater on , also my radio has alot of static that I cannot hear and my windows switches are having trouble lowering the windows and also my lighting no longer works it worked a week ago and now it doesnt , could I be having an electrical problem ..

yes, as you probably know, several things can be on one ground, so if one thing goes bad out of that group it will mostlikely effect the others, I would also take a look at the body control module, it may have a burnt connection, as i have experienced so many times, if you havent checked all of the fuses do so and get back to me.
thanx

My car has no heat. I performed the EATC test and only code 024 showed up. Can anyone tell me what the code means?

DTC 24 Blend door short or failure-You gonna have to go visit the dealership this is a very complicated issue, involving numerous pinpoint tests-

I have a 1999 Mercury Grand Marquis, and I have the opposite issue. The A/C won't work, my car only blows hot air. I think that the problem is the heater control valve but I can't find it.

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Cheers, Ken