My heater works and everything, but it is not blowing air from the vents as much as it should. When it is on High, there is hardly any air coming out. I swapped out the ac box and blower motor for the ac delete ones, (not sure if I need to swap anything else out). What could be wrong?

 

Any ideas?

 

Make sure that there are no holes in your hoses. It sounds like your haven the same problem i did. I had a small hole in a hose coming off the plenum. I ended up buyin a blower motor thinkin it was that problem but I found the hose and now im stuck with an extra blower motor

 

I checked the hose that goes to the blower motor and there were no holes in it.

 

I'll assume you cleaned out the donor box before you installed it.

Do you hear the blower motor through all speeds? Does it sound like it's actually blowing full speed? You should hear it change pitch as you go from low through high.

It's possible the interior doors are not moving as they should. Do you feel air moving from a vent it should not be coming out? Ie coming out the floor when you're on defrost etc?

Can you grope around under the dash and feel if the box is leaking air externally?

 

1. The box was cleaned before being installed.
2. I can hear the blower motor through all speeds, and it changes pitch for all of them. I am not sure how strong it should blow on high but mine feels like it should be stronger than it is.
3. I am not sure if it is coming out vents that it shouldn't be coming from, but i'll check.
4. I couldn't feel any leaks under the dash after I did some sealing to the box, and I felt a small leak around the box under the hood that I will be fixing.