A.C. Issues
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New User
Joined: Jun 2005
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A.C. Issues
Read through several pages in the forum and didn't run into this one so I ask. '02 F-250 SD 7.3 A.C. cuts off at speeds >62 M.P.H. Anything below works like a champ even idling in traffic. Get on the highway above 62 and after a few seconds air begins to warm. You don't get cold air again until your speed decreases below 62. While I'm sure 62 is not a magic number for this type of problem it is mine, anyone else? Whats the fix?
Hotshot
Joined: Jan 2004
Posts: 19,760
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From: St Louis
Haven't seen anyone with that problem before....
On your truck, the compressor clutch is controlled directly by the computer (via a relay). Therefore, I can only suggest that the computer is either acting on an incorrect sensor input or mis-handling the data that it is receiving.
A scan tool looking at live data would be recommended to look at several of the A/C related PIDs to get a better picture of what's going on.
Steve
On your truck, the compressor clutch is controlled directly by the computer (via a relay). Therefore, I can only suggest that the computer is either acting on an incorrect sensor input or mis-handling the data that it is receiving.
A scan tool looking at live data would be recommended to look at several of the A/C related PIDs to get a better picture of what's going on.
Steve
Lead Driver
Joined: Dec 2006
Posts: 7,092
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From: San Diego, CA
I don't know what the problem is, but 62mph corresponds to 100km/h. It's acutally 62.5mph but it seems that whatever it's doing is triggering off of 100km/h (bad sensor input, bad data, etc...)
Posting Guru
Joined: Nov 2004
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From: sunny fla sometimes windy
It could be at the high speed it is lowering the pressure and throwing the low pressure switch, will it cut out in neutral if you bring the motor up to the cruising rpms?
If so you need a recharge!!
If so you need a recharge!!
Hotshot
Joined: Jan 2004
Posts: 19,760
Likes: 1,079
From: St Louis
There's absolutely no indication anything is wrong with his charge level. If there were, it would not manifest itself in this manner.
Again, it's a computer or sensor related problem since it appears to be exactly repeatable at exactly the same vehicle speed.
Steve
Again, it's a computer or sensor related problem since it appears to be exactly repeatable at exactly the same vehicle speed.
Steve
Posting Guru
Joined: Nov 2004
Posts: 2,155
Likes: 1
From: sunny fla sometimes windy
Let him try to bring it up to the same rpms and see if it will recreate it, before telling him to go spend money at a shop!! If the truck hasn't been recharged since it is new it is probably due!! Yes when the vacum gets increased from the higher rpms it will lower the pressure enough to cause it to cut the low pressure switch if it is just a bit low on freon!!
