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rpmdiag, Tech and Instructor
Category: Ford
Satisfied Customers: 7739
Experience:  Since 1975
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2010 Ford Expedition Limited EL. When its really hot out the

Customer Question

Hello - 2010 Ford Expedition Limited EL. When its really hot out the AC will turn on with a full force of air for about 4 seconds, then just die out. The compressor is spinning and the rear AC works fine. Sometimes turning it off and on or going to manual then putting the temp up to 90 then slowly back down will cause it to work, but as you are driving it could just out of nowhere blow full force then shut down again. I have replace the resister that is located under the glove box however the problem still exists. Any thoughts?
Submitted: 1 year ago.
Category: Ford
Expert:  rpmdiag replied 1 year ago.

Hi, I’m Ron and I can help you.
I have been in the auto repair business with my own shops since 1975 and also teach automotive repair. I am confident we can resolve your problem together. Please understand that I don't know your skill level. In most cases when you have a problem with the way the vehicle performs, specialized tooling is required to acquire computer data/information or engine testing results. We didn’t build these complicated vehicles; we just diagnose and fix them. Also understand that I can't see, smell, hear, or touch the vehicle either, so it may take a few replies to get to satisfactory results. I am also going to direct you with the fastest, easiest and most common things to check first. Please be patient and permit me to do what I do best.
I also try to give all of the information you may need, expecting a “positive rating” in return. I will also continue assisting you after you have rated me, if necessary. If there is any reason I cannot get a positive rating, please let me know why “in advance”, so I can go another direction for you. I am sorry you’re having this problem; I’ll help you through it.

This is all controlled by one of your modules and the only real way to test it is with a scan tool set in bidirectional mode where you can operate the fans from the scan tool. There can also be a programming issue that can also fix the problem, we'll know more later after the scan has been done.

thanks, Ron

Customer: replied 1 year ago.
Ok so the only way I can diagnose this with you is by either purchasing a bidirectional odb2 scanner or bringing it to a mechanic? I did bring it to a Ford dealer and they saw the condition, applied a TSB to the computer and it was working when I picked it up. Which it will do if I park it in the shade. But in full sun, it gets real hot inside and then it becomes unreliable until it cools down.
Expert:  rpmdiag replied 1 year ago.

Okay, a scan tool costs over 6K dollars. The dealer should have retested their TSB to be sure it went in right. The module itself may be defective then.

Thanks again, and please don't forget to rate me and keep this link in case you need me again later on.


Customer: replied 1 year ago.
ok so to be clear, the only advice I'm getting is that it can't be diagnosed without going to a dealer or other local mechanic?
Expert:  rpmdiag replied 1 year ago.
Unfortunately, these things do happen. Sure hope you don't let this effect my ratind, I'm just sharing the news with you.
Customer: replied 1 year ago.
Hi Ron, I understand however based on the short description I gave you I'm a bit surprised its immediately to the ACC control unit. I've gone through the diagram of all the areas that could cause an issue, even a grounding issue that is loose could do this. I was looking for someone experienced who could help me trace the path to rule out the relay, wiring harness, blower switch, resistor, etc especially where the same control unit works fine for the rear of the vehicle. Thanks.