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Marc, Technician
Category: Car
Satisfied Customers: 1888
Experience:  33 years exp. automotive repair NYS emisisions repair cert.
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Ford f150: ac turns on at full blast... what should i do

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i have a ford f150 supercrew 2003, when i turn off the truck and turn the key to the off position my ac turns on at full blast... what should i do?

This problem is usualy caused by moisture in the interior fuse box or Generic Electronic Module (GEM, attached to the top of the fuse box). I have had some sucsess with just drying them out (put a small fan on the floor blowing up on the fuse box), But if there is corrosion inside the fuse box you may have to replace it.


Now the the real problem has to be fixed Ford F series trucks have an ongoing problem with leaking windshields you need to get the windshield resealed to prevent this problem from happening again. A professional glass installer should be familiar with this problem and correction.

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Customer: replied 8 years ago.
That would make sense since sometimes i feel water fall on my feet when driving and it did rain last night.... i only have to dry the interior fuse box nothign else??

Sometimes these two components become so corroded that drying does not work so it becomes necessary to pull the fuse box and GEM down and open it up, to clean the connections or replace one or the other. Always check the plug connections for water before replacing.

If that does not work you will have to pull it down and clean or replace it and the GEM module.

Make sure you disconnect the battery before attempting to unbolt the fuse box (if drying does not work)

Don't forget to get the windshield sealed or you will be right back in the same boat.

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