Truck is a '99 SC.

Ambient air temp.: 90º
Relative Humidity: 57%


Air discharge temps:

110º -- interior temp/engine off
(control set at MAX A/C, fan at High)
80º -- 30 sec. -- idle speed
58º -- 2 min. -- city stop & go
50º -- 3 min. -- same
48º -- 5 min. -- same
44º -- 7 min. -- same
40º -- 8 min. -- 55 mph
38º -- 10 min. -- same
38º -- 12 min. -- same
(control set at A/C, fan at High)
50º -- 15 min. -- same
(control set at A/C, fan at "3")
42º -- 18 min. -- same
52º -- 25 min. -- idle
(control set at MAX A/C, fan at "3")
42º -- 27 min. -- idle

Times are elapsed time from engine startup. Controls were set right after previous temperature was recorded. City driving, 35 mph max.

Draw your own conclusions.

[This message has been edited by Dennis (edited 05-12-2000).]

 

It is hard to diagnose the problem from here, but if the compressor never shuts off an overcharge could be the problem. The compressor cycles on a low pressure switch. Outdoor air could be leaking in by a badly sealing or partly open vent door and would keep refrig pressures high. I assume because the engine doesn't overheat the condensor coil isn't blocked.

 

I finally took my truck in on Monday to have the A/C checked. I had two problems one the A/C was not cold or not as cold as it should be, the other problem is that the A/C blower fan seem to blow slower on MAX A/C than A/C(the opposite should be true).Well the part about the A/C fan was my fault, a plastic bag got sucked up in the passenger floor vent and got stuck and slowed the air flow because MAX A/C draws the air from a duct from under the dash. The A/C problem took a little more work first they thought it was a leak somewhere in the system but the test came back negative, then they thought it was a compressor switch, they replaced that and recharged the system but the A/C was intermittent. So they looked at it again and found a gasket on the condenser that was leaking and some how because it was in the condenser the standard test could not work. I do not know anything about A/C's so everything he told me went over my head so I just took his word for it. Now that it is fixed the A/C is ice cold. So if your A/C is not cold and still under warranty like mine take it in because it is not normal.

 

Yesterday, 98 degrees and truck sat in the sun all day until 5:00pm. AC set on max with fan on high. Two miles at 40 mph I had to turn the fan to 3 because it was too cold for me.

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Mine: FOR SALE SOON...1997 F150, XLT, SC, Oxford white/maroon 60/40 cloth, 4x4 ORP, 4.6L, 3.55LS, 17" ORP wheels w/GY AT/S LT265/70/17, auto, 6 CD,Towing package, alarm, Rhino grill guard w/PICCA lights, dual exhaust. Bought new June '96

Wife: '99Explorer Limited,pearl white/tan leather,4.0L,4:10LS,CD,sunroof,towing pkg.,alarm. Bought new Sept. 1999

Next: 2001 F150 XLT SuperCrew, 5.4L, 4x4,3:55LS,tow pkg. etc.......

Previous: '65 Mustang 289 HiPo, '70 Chevelle SS 396, '70 Vette Conv. 350/350, 72 Datsun PU,'74 Vette TTop, '79 Blazer, '81 F150, '83 Bonneville, '84 Gran Marquis '89 TBird Super Coupe 3.8L SuperCharged, '93 Explorer 4.0L

 

The A/C on my month old SuperCrew just quit today. Not entirely, but the air isn't cold at all. I have an appointment first thing tomorrow to get it fixed so I'll post results of the trip after that. Of course it is about 90 today, so I am pretty ticked about it.