Year: 2002
Make: Mazda
Model: Protege 5
Engine Size: 2.0
Refrigerant Type: R-134A
Ambient Temp: 90
Pressure Low: 45
Pressure High: Unk
Country of Origin: United States
2002 Mazda Protege 5 - After 110,000 trouble-free miles, my A/C recently began acting up. The green light in the A/C switch on the dash began flickering oddly - No particular pattern to it . . . . sometimes it flickers on and off as fast as you can blink your eyes, other times it shuts off completely for 2 or 3 seconds or even longer - Occasionally, it's off for half a minute or two before it comes back on
When the green light is off, so is the compressor clutch and both of the radiator fans. When the light flickers like crazy, so do they
Seemed like a possible issue with the relay which engages the clutch to me, so I did some poking around and found that there are three identical relays . . . . one for the A/C, one each for the headlights and tail lights, so I swapped the A/C and headlight relays - Nothing changed. I pulled out the clutch relay and jumpered across the socket with a paperclip. With the engine idling, about 15 seconds or so later the overpressure vent on the back of the compressor blew and I had a huge freon and oil cloud blowing out from under the hood for about 15 seconds - The wife (who had her head under the hood at the time) commented 'You blew it up' and went inside to change her drawers
I recharged it with a 15 ounce can of freon which also contained 3 ounces of oil - 45 psi low side pressure on a 90 degree day. Seemed to work OK for a day or two, but it's pretty much back to doing the same thing it was before. It's as cold as ever when it's running, no problem there but when the light begins going out (especially for longer periods) it begins blowing pretty warm
One last clue I discovered just this afternoon which may be the 'key' to the whole puzzle - We always run the blower fan on position 2 because of course the air coming out is colder when you force less air through the evaporator . . . . and it's quieter inside the car. Can't remember the last time we used anything other than 2 on the fan switch. The system cycles (somehow) as needed to prevent freezing up the evaporator . . . . the green light never goes out and you never hear the clutch kicking in or out, nor do the two radiator fans ever quit blowing - You experts will know what it's doing (bypassing?) to prevent freezing the evap without disengaging the clutch, but I haven't a clue - In my old 240Z under the same conditions, the clutch just cycled in and out
Anyway . . . . today I find that if I run the fan on position 3, the system works perfectly all the time, hour after hour - The green light on the dash never flickers. The air coming out isn't quite as cold as if we had it on 2 like we normally do, but it cools the car quite effectively . . . . I assume it's working fine because the system no longer needs to 'cycle' like it does when the fan is blowing slower
So - What's not cycling properly and what do I need to do to fix it? I appreciate all comments because (as usual) I'm still (re)learning half the stuff I *thought* I already knew!
Don
Probably just the fan switch, if it is truly mechanical manual controls. Up to the early 90s practically all Japanese cars were built with an extra circuit in the fan switch that closes in any position but off, that circuit then passes on to the A/C button.
It is complicated to properly recover from blowing it up, really you should remove all refrigerant and oil then recharge both to factory specifications. At least check that the relief valve is not leaking, they don't always reseal fully.
Edited: Thu June 24, 2010 at 4:30 PM by mk378
I doubt it's the fan switch
Normally, the little green light is always on . . . . never goes off. Now, when running on position 2 it flickers off and on to keep the high side pressures under control - When I shorted across the relay (which forced the clutch to be on all the time) it promptly blew the high side pressure vent. It would do it again now if the green light wasn't going off and on. Running the fan switch on position 3 keeps the evap from freezing up (my theory at least) and it works perfectly
As to the recharge - It still worked OK after the blow-up. I ran it that way for a week or so (no flickering of the light) but it didn't blow as cold as it did when the system was full of freon, so I added the can. No signs now that it's undercharged and it works perfectly . . . . so long as you're not using position 2 which forces it to 'cycle' . . . . which it seems it can't do any longer
What usually happens in a modern (2002) Japanese system to prevent the evap from freezing up? The clutch never disengages (which is why I thought I was safe jumpering the relay) but somehow the system bypasses to reduce the cooling efficiency when it doesn't need max cool . . . . or at least it used to
Don
If you want to get at the root of your problem, you need to see the high side pressure. If you don't have gauges, rent, borrow, or steal (kidding on that one) a set. Auto Zone has them for rent or loan. Get a schematic for your system. You can get a complete cd for your vehicle for about $25..
Sounds exactly like the Chevy Malibus and the Olds Intrigues ---a/c control is energized through the fan switch which has a master "off" position-- hence two brushes make contact as the fan switch rotates through the various speeds- since you always use fan speed two-- the brushes have been arcing in fan speed two position- when you rotate to position three- they have fresh copper to contact- so they make better connection- and run the a/c circuit. Pretty simple-just pull out the blower motor selector switch and clean and polish the brushes and their respected wiper board- use a pencil eraser-- and never see that green light flicker again----BTW stay out of the relay-- it is not the problem....control heads do not flicker just because the relay is commanded on or off.....
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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......
Jumping the a/c compressor relay will never energize the fans- they should have their own relays--when you put 12volts to the pump- it creates head pressure and the fans are not on to keep the pressure down-- the high pressure cut-out switch cannot do its job either- because it would normally turn off the relay that you have decided to run full time- that is why you are spewing out refrigerant- why not let the system work as designed and fix the input problem-- the control head is an input into the ecm- and if it is blinking at a random pace- it is called "intermittent" and needs to be fixed-- there is no feedback to the control head that tells it of an overpressure condition-- the overpressure condition is information fed to the ecm that can't do its job because you have decided to jumper the relay. Quit jumpering the relay.
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The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......
The problem is at the control panel. Clean or replace the fan switch. It really is that simple.
Quit jumping the relays! If you force the compressor on and the condenser fan is not on, an overpressure will develop in a very short time. If the system is working as designed (no jumpers), failure of the condenser fan will just cause the compressor to shut down before the relief valve opens.
Actually, if YOU go back and read all the posts you'll find out that mk378 TOLD you where the problem is (along with several others). You just refuse to accept their advice and want them to give you advice that fits with what YOU think is wrong with the system.
My advice: GO FOR IT! Do what you will. Its your system and your money.
Without a high pressure reading you have no idea what is going on. You can't claim an overpressure event based on a guess.
After blowing the HPRV with the jumper wire stunt, you have no idea how much oil & refrigerant is in the system.
You are not really sure what relay you actually jumpered to produce this disaster.
You have no idea how the system works, but because you owned a 25 year old japanese car from another maker - you believe it should work the same way.
You really don't know much. But you think you know more than the people on this board earning a living fixing MVAC. Good luck with your car.
B.
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"Among the many misdeeds of the British rule in India, history will look upon the act of depriving a whole nation of arms, as the blackest."
~ Mahatma Gandhi, Gandhi, An Autobiography, M. K. Gandhi, page 446.
My 2002 protege5 is giving me issues, I put a can of R12 in till the gauge reached 30psi. Then started the car turned the A/C on and the blower on max and emptied the rest of the 6 oz can in. Initial reading when I hooked the gauges on was 0 psi. Now I would expect the clutch to engage but hasnt thus far. Last night i seen a post that if the high side has no pressure the clutch may not engage and to bypass it for a few minutes to pressurize the high side. So I have done that, my readings now are 40- 45 psi with the clutch engaged and 70- 75 psi when its stopped. The problem I still have is when i reconnect the harness and remove the bypass, the clutch still will not engage. thoughts?
You should start a new thread.
Upon finding a system at zero pressure, that means there is a major leak and the first step is to find the leak. Merely recharging is futile because it will leak out again.
Did you really put in R12? A 2002 car will have R134a. Using R12 will cause damage.
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