3rd & 4th Generation (1992–1996 & 1997–2001)Toyota Camry Discussion for years: 1992-1996 & 1997-2001
Topics of discussion range from fuel economy, safety, modifications, performance all involving America's favorite family car, the Toyota Camry.
Sympton is no compressor engagement. The problem has been narrowed down to the fact that the MG CLT relay will not energize. If jumped the compressor works fine. I think it may be the D3 diode or the AC switch.
I don't know how to remove D3, to test it.
I suspect the sw/ because when I tested the plug to the AC amp I got a constant 10+ VDC on pin 10 even with the key out of the ignition. Expected was 4V sw/ on and 0V sw/ off. The sw/ LED works correctly.
the compressor won't come on if the A/C pressure is too low. ie. the A/C low pressure switch will open signalling the A/C control unit. Check your pressures.
I don't think it is the press sw, because the compressor would not have ran with the relay jumped. The B+ would not have been available. The fluid did look fine in the receiver, when running.
Doesn't the press sw/ shut the sys down after it starts and recognizes the problem?
Just a reminder that I am working on a manual AC, not an automatic AC. There is no "AC controller".
You may know that a relay has two signals. The switching signal and the power signal. I would try to see which one of those signals is not working as either will not enage the clutch. It may help trace the problem. It could still be a defective pressure switch. Can you check it?
__________________
1995 Camry Wagon LE. 2.2 4cyl, 5S-FE, Auto, 187K
Last edited by Stillrunning; 10-06-2008 at 03:20 PM.
The switching side of clutch relay had only .4V when it was supposed to be closed. When I jumped the power side the AC worked. If the press sw/ was open, the AC would not work, as it would cut the power.
Does the comp sw/ not only come into the mix after the compressor has engaged? After it recognizes that the press is too low, or high.
How do you remove D3? It is the diode at the very end of the panel. I don't think it is the problem, but it is in the cct and I would like to confirm it, one way, or the other.
I don't have Solara A/C info so can only give general ideas. Another thought would be the evaporator temp sensors. They also disengage the compressor clutch to prevent over cool and are the reason you get compressor cycling. They are going to be hard to test as you may have to remove the evap.
__________________
1995 Camry Wagon LE. 2.2 4cyl, 5S-FE, Auto, 187K
I don't think it is the press sw, because the compressor would not have ran with the relay jumped. The B+ would not have been available. The fluid did look fine in the receiver, when running.
Doesn't the press sw/ shut the sys down after it starts and recognizes the problem?
Just a reminder that I am working on a manual AC, not an automatic AC. There is no "AC controller".
If the static pressure is low enough, then it won't allow the A/C to come on at all without forcing it on as you did by jumping the relay. You should be able to check the switch itself withan ohm meter. By controller I mean the 'A/C amplifier' or whatever Toyota refers to it.
If the static pressure is low enough, then it won't allow the A/C to come on at all without forcing it on as you did by jumping the relay. dave mc
dave, that's why I asked if he had cold air when the clutch was jumped. I don't suspect low pressure because he did have cold air. I don't think there would be enough refrigerent for cold air if staic pressure was too low to allow the clutch to engage. Taking pressures wouldn't hurt of course.
__________________
1995 Camry Wagon LE. 2.2 4cyl, 5S-FE, Auto, 187K
The clutch relay is energized when the fan is on and the AC button is on. By jumping the point side of the relay, I proved that the remainder of the cct works properly. The problem is with the coil side not getting it's power to close the relay.
The AC sw/ has two diode/resister ccts in // between the LED and the amp at pin 10. I have no idea what the purpose of these are, but am wondering if this is the cause of the constant, high voltage as stated in first post.
To avoid confusion with the auto AC that uses the AC controller, I thought it prudent to make it clear that the manual AC uses an amp and input from the ECM.
For further info please visit http://camrystuff.com gen 4 electrical and AC manuals.
My FSM only has a test for the A/C switch continuity and does not mention the diode or resistor. Continuity good - switch ok, continuity bad - replace switch. Other suggestion that you probably already checked is the revolution detecting sensor on the compressor. Loose belt or bad sensor will tell ECM to not engage compressor. 1MZ-FE resistence at sensor terminals 1 and 2 at 68F = 65-125 ohm. There are tests for the amplifier but too long to post here.
__________________
1995 Camry Wagon LE. 2.2 4cyl, 5S-FE, Auto, 187K
Pull the clutch relay and check pin 1 for +12v with the car started. If you are not getting that, then there is an issue with the fuse or the connections to the relay. If you do get that, turn the car off, re-install the relay and pull the A/C amplifier connector off. Now start the car, and briefly ground pin 12 of the amplifier cable (ie short pin 12 to pin 5, or safer, use a 10W, 10ohm resistor approx) and see if the clutch relay gets energized. If it does, your D3 diode is ok. If it doesn't, turn the car off and take an ohmeter reading across pin 12 of the cable (neg meter lead) and pin 2 of the clutch relay socket (pos meter lead). You will need an extension wire to reach between the cabin and unde rthe hood of course. You should get a low ohm reading. reverse the meter leads and it should read open (ie infinite resistance).
If the D3 diode is ok, then you need to consider the other A/C amp inputs that can prevent the amp from energizing the relay. You should also at least check the pressure switches by again leaving the A/C amp connector disconnect and with the car running, measure the voltage at pin 2 on the cable. It should be +12V. If it isn't, then you may have a faulty pressure switch or the A/C pressures are too low or too high.
When you said jump the relay, what terminal were you jumping?
The A/C mag clutch relay has a constant 12V feed to terminals 1 and 5 when key is on. The A/C amp provide the ground to complete the circuit and energize the relay.
BTW, the pressure switch will open up if the system pressure is too low, which will in turn signal the A/C amp to disable the A/C clutch. Just jump the terminals at the pressure switch and see if the compressor engage. By jumping the relay you had by-passed the pressure switch to power the clutch.
N.E.O.
Last edited by new echo owner; 10-11-2008 at 03:10 PM.
Thanks for all the input guys. Unfortunately, my daughter has left town with the car and won't be back until Friday. I'll try some of your suggestions and get back to you then.
Wow, I'm guessing, by Dave's latest reply, that D3 doesn't come out. I'm glad I didn't try too hard and bust it up.
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.
ToyotaNation.com is an independent Toyota/Lexus enthusiast website. ToyotaNation.com is not sponsored by or in any way affiliated with Toyota Motor Sales, USA, Inc. The Toyota, Lexus and Scion names and logos are trademarks owned by Toyota Motor Sales, USA, Inc.
Linear Mode
