Hello I have a 1997 Ford Crown Vic my question is when the AC is running air conditioning blows Cold And then sometime it blows hot for about 60 seconds and then it blows cold again
6 Answers
several ways possible, easier to get a performance test and measure values, then note duct temp, then make it act up, if you have to take iot for a drive, that tells your tech different info than if it acts up at idle. systems use different parts and on the same car multiple systems and partts could be in use. shortcut? coupon for ac check, get the diag. you have to go to a real technician, though.
Theres switches that react to pressures and temps, theres relays that react to throttle opening WOT, theres hi or lo side switches, ambient pressure switch, situations make the concern possible as far as refrig. related, but on the ducts, theres modes, and supply to the doors, theres electronic, those have readings based on sunload, ambient. etc. what system do you have. a control that acts up can actuate temperature blend and have erroneous info, or because it wants to, or because the blend just decides to get stuck, or strips a gear, or runs into a pen that fell down inside. vacuum sources can have a cracked plastic part, or leaky diaphragm, or connection trouble. so, that's why the dealer is best and fastest, service bulletins and familiarity. too much good stuff, man. But electronic ones can indicate a set of tests with a self check of the control in the instrument panel.
ask a service advisor in the service drive what has been fixing that concern with that year and model, he might run the first test and advise the likely answer or worst case and try to get you to test further for the actual , on yours. Thats the way they are. some very simple, some you have to just check this, that, and the other.
possibly, yes, but is that all you would do to correct the system's operation?
The reason its important is there is a procedure and bench test for these hi and lo pressure switches that helps diag, but theres correction on the car. The system pressures must be read and corrected for ambient and conditions before. The tsb we used in 94 and 95 may be reissued, or another switch part number may have been the 97 correction. thats how Ford tries to get and keep them corrected once.
