Not enough air through vents - Ford A/C problem
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Customer Complaint: This 2008 Ford F-250 with a 5.4 liter engine came to the shop with two separate air conditioning problems. The first problem was the A/C compressor would shut off going down the road and the truck would not blow cold air. The second problem was when the A/C was working, it would not blow enough air through the vents like it was designed to operate. This is a work truck, so the customer wants both problems fixed.
First Thoughts: I have worked on many Fords with A/C issues, but I was not the technician over the first of the customer’s problems. Another technician was tasked with figuring out what was wrong with the A/C compressor and why it was randomly turning off.
He found that the plug-in for the A/C compressor was messed up and losing connection. Easy fix. Issue number one was corrected.
Apparently, this is a major issue with Ford compressors around this year. I know I have fixed this issue many times because the connector will become bad over time and cause connection issues. If you have A/C compressor issues with a Ford like this, then this may be your problem.
The other technician had to do another job, so I was tasked with finding out why this truck was not blowing a lot of air out the vents.
Diagnostics:
There can be a few reasons why there is not enough air coming out of the vents.
Here are some issues that I have run into:
The blower motor/ resistor is not functioning correctly.
The cabin air filter is very dirty to the point no air can pass through.
A component (HVAC door) has broken and is not allowing air to pass through.
The A/C evaporator core is clogged and not allowing air to pass through.
Here are some easy steps to figure out if you have one of these issues.
The blower motor/ resistor is not functioning correctly.
The way you check this is easy. Just see if all of the blower motor speeds are working. If they are working and you can hear/ feel a change in the air speed coming through the vents, this may not be your problem.
All the blower motor speeds worked on this truck so I knew that wasn’t the problem.
The cabin air filter is very dirty to the point no air can pass through.
This is a simple process also. Does your vehicle even have a cabin air filter? Some vehicles do not. Do a quick Google search to see if your car does, take it out, and replace it if it is dirty.
This truck did not have one so I knew that was not the problem.
A component (HVAC door) has broken and is not allowing air to pass through.
This one is a little harder to diagnose but not impossible. It is possible that a door inside the HVAC housing has broken and lodged in between the airways.
I have only seen this once in my career and it was on an older Ram 1500. The recirculating air door had broken and was covering the airway to the blower motor. This did not allow enough air to flow through the vents.
If all of your HVAC doors (Vents/Floor/Defrost/Temperature/Recirculating) work then this may not be your problem.
This truck had all of the HVAC doors working, so I knew that was not the problem.
The A/C evaporator core is clogged and does not allow air to pass through.
This check requires a special tool. It is called a borescope. A borescope is a tiny camera that can maneuver through tight areas.
I used my borescope to find this truck’s evaporator core. What I found was pretty nasty.
This is the borescope that I used. Link here.
This evaporator core was extremely clogged!
No wonder there was no air coming through the vents. It could not get past the evaporator core!
After a few hours of removing the dash, I was able to remove the evaporator core and install a new one.
Dirty Evaporator Core
How did this happen?
The reason why this evaporator core was this bad is because of a few things.
This truck drove down many dirt roads.
This truck was not very clean. There was dirt all over the place, but it’s a work truck, what do you expect?
It does not have a cabin air filter. This truck does not come equipped with a cabin air filter, which is unfortunate. A cabin air filter captures a lot of unwanted particles from the truck.
How can you prevent this?
Try to limit dirt roads if you can.
Clean your vehicle. Inside and out.
Replace your cabin air filter if you have one.
After replacing the evaporator core in this truck, the air came through with plenty of volume and coolness!
Fixed!
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