2002 ac problem

First step is to make sure the system is charged with the proper amount of refrigerant.

Will an OBDII Diagnostic bring up any codes?

O2-

This sounds familiar... didn't someone just have this same problem, spent "a lot of money" charging the refrigerant, then the problem was compressor sensor (or maybe just compressor) related?

Google is your friend. Did a Google in groups for "ac flashing" in alt.autos.toyota and best info is: " It's one of the functions of the AC Amplifier module - when it engages the compressor clutch, it monitors a rotation sensor inside the compressor versus the engine RPM. If the speeds don't match, it thinks the compressor is failing and locking up, or the clutch is slipping and is going to burn up - they can't take too much slipping before they get red hot, and you have a fire. So the module shuts off the clutch to keep from breaking or throwing the drive belt, and the blinking light is the trouble indicator." I also agree with qslim, low charge could possibly cause a problem but, a belt is a more likely first choice. Dave

I think a belt problem is less likely than a charge problem. If the belt was loose, you'd have noises and also problems with all the other accessories. About 3/4 of the AC problems we see in the shop are due to a low charge. You certainly could go probing for problems with the amplifier, pressure switch, thermistor, or clutch, but the first step a tech would take is placing a manifold gauge set on the system and making sure there is proper pressure in the system. Or at least quickly pop the low side schrader valve open and see if you have any refrigerant at all.

I agree with you and am not recommending an out of the ordinary test sequence for a tech but, the first thing a DUI'er could do is check the belt and that's the point I was trying to make but guess I wasn't clear on. I'm not sure on his model but on my '97 Camry the serpantine that drives the ac pump drives the alternator and possibly the p.s. and is set to proper tension by a manual tensioner bolt instead of a spring-loaded tensioner. Out of all the accessories, with the exception being the p.s. being forced into the stops, the ac compressor takes the most belt energy to turn and will be the first to slip if there is a problem with the belt. The amplifier would interpert this slippage as the compressor locked up or clutch slipping and shut the ac off. I've seen belts slip and not make a noise and you probably have also, although I agree it usually will. A rule of thumb for a DUI'er is to grab the belt in the middle of the longest span and twist it sideways. If it twists to appx 45 deg. with little resitance then it should be tight enough. This is NOT an end-all test though, there are specific deflection and/or tension specs. which should be adhered to. HTH, Dave

davidj92 wrote: snip

Another check I forgot to mention is to look at belt when twisting. If it has a lot of cracks on the groove surface, portions missing, delaminating or is glazed then it needs to be replaced.

Thats a good point. I do suppose not everyone has a gauge set sitting around.

I recently had my AC led flash on my 2003 Camry. I took it to a mechanic and all they did was pull out the fuses and the relay for the AC and reinserted them and it worked. I am not saying that this is your problem, but it's a start. In my case, my AC was not making noises at all. It went from working to a blinking AC LED. Apparently I must have had a bad contact.