Heater Not Very Strong?

**MattF** · 01-01-2014

When I have my A/C on during the summer it works great, real strong and everything. However when I use the heater it makes the car warm and if I put my hand up to the vents it feels warm however I feel little to no air blowing out of it. Any ideas why this might be?

**Fivefingerdeathpunch** · 01-01-2014

I'm sure if you searched on this topic, you'd find several hundred threads regarding heat problems in the winter time.

Take some time and do some reading and maybe you'll figure it out.

**MattF** · 01-02-2014

I already did a search around of it on here and online, only found 11 threads matching "heat problem" in the thread title. Most of them cited some problem with the blower motor, but if the blower motor didn't work my A/C wouldn't work either correct?

**tc300** · 01-02-2014

Check the hater core lines back by fire wall.. Should be hot

**stocker** · 01-02-2014

I don't think the heater core has to do with air flow coming out of the vents only the temp of the air. I can't necessarily help MattF but continue different searches like "heater" "heat issue" "heat" etc and see if you find any better information. I'm sure someone more knowledgeable will post up soon.

I'd post some more info too like is this the first time you've had the problem, year of car etc.

**sseilmnop** · 01-02-2014

Which thermostat are you running? I put 195 back in during winter to get more heat. Make sure you are not low on coolant and you don't have sludge build up in radiator. Sludge can actually stop the flow of coolant through heater core.

**MattF** · 01-02-2014

The heater has no problem producing the actual heat as I have stated because when I push my hand up to the vent I can feel warmth and it has no problem heating up the car, there is just very little air flow coming out of it which causes it to take longer to heat up the car.

**sseilmnop** · 01-02-2014

Originally Posted by MattF

The heater has no problem producing the actual heat as I have stated because when I push my hand up to the vent I can feel warmth and it has no problem heating up the car, there is just very little air flow coming out of it which causes it to take longer to heat up the car.

Then you have a fan problem.

**02NavyBlue** · 01-02-2014

Originally Posted by sseilmnop

Then you have a fan problem.

Well he said using the A/C blows strong. The air doesn't go through the heater core when in the cold air selection. So the blower may be fine.

**sseilmnop** · 01-02-2014

Originally Posted by 02NavyBlue

Well he said using the A/C blows strong. The air doesn't go through the heater core when in the cold air selection. So the blower may be fine.

He said in the summer it blows strong. Does the ac blow strong now?

Did he check his coolant level?
Did he check for sludge?
What year make model of car?
Digital climate control or manual?

**02NavyBlue** · 01-02-2014

So is a good amount of air coming out of any of the vents? On high speed of course. If not the heater core may be clogged (externally)

**MattF** · 01-02-2014

Coolant level is fine but I haven't checked for sludge. 2002 Grand Prix GT. Manual Climate Control.

A/C blows fine now I have tested it. And even now, my car sits outside so when I get on and turn the heat up all the way the air is cold but blows strong, when it starts to get warm the force of the air coming out of the vent gets diminished.

It's pretty linear across all the vents, none of them are blowing stronger than any of the other ones although every once and a while the air coming out of them will get a bit stronger.

**Scottydoggs** · 01-02-2014

run the a/c for a while, see if the fan slows down in the same time as the heat.

thinking your fan is dead. how does it sound? any vibrations, or sounds from it?

**02NavyBlue** · 01-02-2014

So wait, you have the selection on lets say, the face vents, but the air is coming out of all vents about equal? That shows that the actuators may not be in the correct spots.

And only when the car is warmed up? That's odd. yeah maybe it has to do with the blower warming up and going slower like scotty said?

**sseilmnop** · 01-02-2014

Did you check coolant level in the overflow tank or in the radiator?

Fan doesn't blow hot air, it takes outside air and blows it across the heater core to get heat.

Is there a recirculate option?

**02NavyBlue** · 01-02-2014

Originally Posted by sseilmnop

Fan doesn't blow hot air, it takes outside air and blows it across the heater core to get heat.

I meant that as the blower motor itself warms up from the electrical current and acts up.

**sseilmnop** · 01-02-2014

Originally Posted by 02NavyBlue

I meant that as the blower motor itself warms up from the electrical current and acts up.

Should be a brushed DC motor with fan speeds controlled by a resistor bank. Hi speed doesn't go through a resistor.

Not common for these motors to slow down from heat. Resistors go bad and electrical connections overheat and go bad but it normally works or it doesn't.

**02NavyBlue** · 01-02-2014

Originally Posted by sseilmnop

Should be a brushed DC motor with fan speeds controlled by a resistor bank. Hi speed doesn't go through a resistor.

Not common for these motors to slow down from heat. Resistors go bad and electrical connections overheat and go bad but it normally works or it doesn't.

I know. I didn't really think the blower motor was bad, it's just odd how it blows fine at first. Also the coolant level has nothing to do with the amount of air that is pushed through the vents.

**Curious** · 01-02-2014

Ok I dont know too much about the electrical stuff but when he said the fan blows fine on heat at first and then as the car warms up it slows down..... could it be the sensor that detects when the cabin is warmed up to the set temperature on the controls... i mean... i can turn the knobs for any temperature between 60 and 90 and the auto controls will slow the fan when the cabin reaches the desired temp. could it be that sensor or whatever controls it.... just a thought.....