A/C vent help
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Mountain Pass
Joined: Sep 2019
Posts: 109
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A/C vent help
1986 F-150 XL 4x4 5.0 efi. My problem is I get very little air out of the vents. The blower motor gets faster as you change the switch to high. You can hear it blowing harder but still little air through vents. You can switch between vent floor or defrost and it changes where it’s blowing but never gets harder. Still very little air. Hot and cold works as the temp changes of the air coming out. Just not blowing hard. So what am I looking for to fix this. Thank You!
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Joined: Jan 2001
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From: Virginia
There are some doors in there you can check when you have it apart, but I have found 90% of the time when I have air problems, the A/C coil is plugged. It gets wet when it runs, and over the years dirt builds up on it and it turns to mud and plugs it up. The only way I have found to fix it is to pull the housing off the firewall and physically clean it out. This is a pain to take apart, but while you are in there you will see some doors you can check also. I am thinking you can do this without draining the A/C system, but I will admit I have never done that before. I remember there being one nut on the inside of the cab you had find and take loose before it would come off.
One other thing; Has anyone ever replaced the fan motor? A lot of these replacement motors you buy now are universal fit. You have to check direction and load the wires in the motor plug properly. If someone replace the motor and it's running backwards, that can affect the amount of air it blows. It will blow air either direction it runs, but it blows a lot more air when it's running the proper direction.
One other thing; Has anyone ever replaced the fan motor? A lot of these replacement motors you buy now are universal fit. You have to check direction and load the wires in the motor plug properly. If someone replace the motor and it's running backwards, that can affect the amount of air it blows. It will blow air either direction it runs, but it blows a lot more air when it's running the proper direction.
FTE Legend
Joined: Nov 2015
Posts: 30,935
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From: Angier, NC
I am with DaveF on the coil being clogged.
Instead of trying to pull the housing on the engine bay side pull the blower motor.
A few weeks back I found the blower motor mount to the HVAC housing was leaking, air did blow good out the vents.
Well before I installed the motor with a new seal to housing I reached inside and found a lot of junk at the bottom & on the coil.
I took out a few hand full of stuff then used my shop air to blow it out better. I am still getting some dirt blowing out the vents as it dries more and the air blows thru the cowl.
It should be pointed out that the resister by the blower motor can have a build up of leaves and can catch fire along with the other stuff and burn the truck to the ground.
CLEAN IT OUT!
I don't have the AC working yet but I am sure it will work better when it is.
I should also point out that I moved the HVAC box from 1 truck to another and though I cleaned it out with the water hose, guess not
Dave ----
Instead of trying to pull the housing on the engine bay side pull the blower motor.
A few weeks back I found the blower motor mount to the HVAC housing was leaking, air did blow good out the vents.
Well before I installed the motor with a new seal to housing I reached inside and found a lot of junk at the bottom & on the coil.
I took out a few hand full of stuff then used my shop air to blow it out better. I am still getting some dirt blowing out the vents as it dries more and the air blows thru the cowl.
It should be pointed out that the resister by the blower motor can have a build up of leaves and can catch fire along with the other stuff and burn the truck to the ground.
CLEAN IT OUT!
I don't have the AC working yet but I am sure it will work better when it is.
I should also point out that I moved the HVAC box from 1 truck to another and though I cleaned it out with the water hose, guess not
Dave ----
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Joined: Jan 2001
Posts: 56,992
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From: Virginia
If you have access to the coil by taking the blower motor out, by all means do that. Taking that housing loose from the firewall is not much fun. But by doing that you do get access to a door there for the defrost. You would not believe how many watches, pens, pencils, etc that I dug out of there. These trucks have excellent heaters if you get it all working correctly.
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Mountain Pass
Joined: Sep 2019
Posts: 109
Likes: 8
***Update***
So I pulled out the blower motor and found the issue. It was slap full of pine straw and leaves. I also removed the resistor and made sure it was clean. Don’t want to start a fire. Blew it all out real good, re assembled and now it blows like it should. Thank you all for the help.
So I pulled out the blower motor and found the issue. It was slap full of pine straw and leaves. I also removed the resistor and made sure it was clean. Don’t want to start a fire. Blew it all out real good, re assembled and now it blows like it should. Thank you all for the help.
FTE Legend
Joined: Nov 2015
Posts: 30,935
Likes: 4,123
From: Angier, NC
Thanks for the up date as it will help others.
You also stopped a fire from starting as all that dried pine straw can catch on fire and burn the truck down.
You will still get some dirt out the vents as I do and I used 150 PSI shop air to blow the system out.
Dave ----
You also stopped a fire from starting as all that dried pine straw can catch on fire and burn the truck down.
You will still get some dirt out the vents as I do and I used 150 PSI shop air to blow the system out.
Dave ----
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