Heater issue

[Retoxtony]

It’s not the first time this happened but last night driving home from a hockey game my heater just stopped blowing. Not all at once, just slowed down till almost no air was coming out the vents. It started whistling like the fan was trying to blow but it was blocked off. Made for a cold ride home. Even at only -7C it got pretty cold in the truck. It did the same this morning on my short drive. Last time it did this it was -35C which made for a really cold drive. Had it into the dealer that time and they say they can’t find anything wrong. Cab filter isn’t blocked, and I can’t find anything that would be blocking airflow.

Just wondering if anyone else has experienced anything similar?

 

[Sly]

Is this happening just on the heat setting are is the air not blowing no matter if set in heat, AC or just outside air?

 

[Sly]

It’s not the first time this happened but last night driving home from a hockey game my heater just stopped blowing. Not all at once, just slowed down till almost no air was coming out the vents. It started whistling like the fan was trying to blow but it was blocked off. Made for a cold ride home. Even at only -7C it got pretty cold in the truck. It did the same this morning on my short drive. Last time it did this it was -35C which made for a really cold drive. Had it into the dealer that time and they say they can’t find anything wrong. Cab filter isn’t blocked, and I can’t find anything that would be blocking airflow.

Just wondering if anyone else has experienced anything similar?

What about speed of the fan, will it do this on low, med, and high?


I would look at the fusses first, second it could be blower relay malfunctioning or the blower it self is going bad. Hard to say without more info, could also be a loose wire somewhere.

 

[Retoxtony]

What about speed of the fan, will it do this on low, med, and high?


I would look at the fusses first, second it could be blower relay malfunctioning or the blower it self is going bad. Hard to say without more info, could also be a loose wire somewhere.

Does it at all speeds. When it was really cold I had the fan set on a lower speed but had to crank it all the way just to keep enough air flow to defrost the windshield. When it happened yesterday and today I had the fan on high already since I was trying to warm the truck up. The way it starts to whistle it sounds like the fan is still trying to blow but it’s blocked. I’m not sure how the ducts work with the blend doors on these trucks but I wonder if something isn’t closing off inside the ducting.

It’s a random issue that the dealer couldn’t replicate so I was hoping someone else had a similar issue so I could point the dealer in the right direction. Trucks still under warranty (30,000 km) so they should deal with it before I start tearing into things myself.

 

[Jmzvet]

If it doesn't throw a code and the problem isn't present at the dealership, they will have no idea how to fix it. Hopefully it's just a random gremlin that will disappear. Especially since you really need and depend on a heater.

 

[Transient]

Is the AC button still illuminated when you're running the heat?

 

[mrcolieman]

It’s not the first time this happened but last night driving home from a hockey game my heater just stopped blowing. Not all at once, just slowed down till almost no air was coming out the vents. It started whistling like the fan was trying to blow but it was blocked off. Made for a cold ride home. Even at only -7C it got pretty cold in the truck. It did the same this morning on my short drive. Last time it did this it was -35C which made for a really cold drive. Had it into the dealer that time and they say they can’t find anything wrong. Cab filter isn’t blocked, and I can’t find anything that would be blocking airflow.

Just wondering if anyone else has experienced anything similar?

From your description it sounds like the all the vent doors are closing at once, causing the then pressurized plenum to whistle as air escapes passed those closed doors. Now the question is what's causing the doors to close? Bad inputs to the control module, bad control module, bad door actuator (although those usually break mechanically and make funny noises)... Going to need to check for trouble codes again to see if anything is stored. Good luck and stay warm!

 

[Retoxtony]

Is the AC button still illuminated when you're running the heat?

No. The Auto function is off as well.

 

[Retoxtony]

From your description it sounds like the all the vent doors are closing at once, causing the then pressurized plenum to whistle as air escapes passed those closed doors. Now the question is what's causing the doors to close? Bad inputs to the control module, bad control module, bad door actuator (although those usually break mechanically and make funny noises)... Going to need to check for trouble codes again to see if anything is stored. Good luck and stay warm!

This is what I was leaning towards as well. Not sure how I’ll track down the actual issue though. I’m hoping that it stops being an intermittent issue and becomes permanent so the dealer can see what I’m talking about.

Now that winter is basically over I wonder if I’ll have a similar issue running the AC through summer.

 

[PistolsFiring]

If not done already may try to get good quality audio/video, if possible. At least this way you have some sort of documentation to go with your dealer visit. May also help the technician in tracking down the problem.