A/C Always on. Can't get it to shut down.

[miroteknik]

Yes I am new, and yes I joined mainly to get an answer for my question. Searched and couldn't find a thread to answer my question, so here goes.

I bought a 1997 Eclipse GS. It's completely stock. Did general maintenance on it, but one thing has me stumped. The A/C is always on and I can't get it to shut off. The green light on the A/C button is always lit up, whether it is depressed or not. I've clicked it on and off a million times, but the light is still on. The A/C compressor runs as long as the motor is running. It is winter and I've been using the heater, it works great. But that A/C light is still on, and its bugging me. I popped the hood today and there was frost on my A/C lines and that set me over the edge. Any ideas or suggestions?

Thanks in advance.

 

[pauleyman]

Are you in defrost mode? Ac is always on if you're in defrost

 

[CountryDSM]

I would second the defrost mode, it does that on my 91 accord.

 

[boost97gst]

Your vent controls work? As in, when you select panel you get panel, floor is floor etc..? To me it also sounds like the defrost is stuck on. But if you want a temp fix you can just pull the fuse for the ac. Or the relay as long as it doesnt control anything else. The AC pushbutton can break too. Dont rule that out at all and in fact its the most obvious of things to check out.

 

[miguelmcv]

I would lean more to the AC button being bad, try to take it off and see what happens, it has to turn off with the ac button disconnected, if it still ON with out the button, then you have some serious electrical problems.

Remove the button and report back the results.

 

[miroteknik]

Thanks guys, I'm impressed with this forum's willingness to help!

No, the defrost is not on. I've even toggled it on and off a few times in case it was stuck. Yes my vent controls work, and I would rather not pull the fuse since that is only temporary

I will check out the button itself when I get a chance. I clicks in and pops out like it should, so it is not stuck... But the backlit green light is always on. At first I thought this was a function to make it easy for the user to see the button when driving, but I am not sure. Are all of your a/c buttons always lit up on your eclipses?

I will check it's electrical worthiness next, and report back.

 

[CountryDSM]

Are all of your a/c buttons always lit up on your eclipses?

It only illuminates when pressed for me anyways.

 

[isantop]

Thanks guys, I'm impressed with this forum's willingness to help!

No, the defrost is not on. I've even toggled it on and off a few times in case it was stuck. Yes my vent controls work, and I would rather not pull the fuse since that is only temporary

I will check out the button itself when I get a chance. I clicks in and pops out like it should, so it is not stuck... But the backlit green light is always on. At first I thought this was a function to make it easy for the user to see the button when driving, but I am not sure. Are all of your a/c buttons always lit up on your eclipses?

I will check it's electrical worthiness next, and report back.

The snow flake should light up at night, but the big green/orange light on top should stay off. If you get pics, we can confirm that the light is always on.

Getting to that switch isn't too bad. Basically, you just need to pup the center vent out and reach in from above. I believe it goes out into the cockpit, and is held in place with a little jut-out clip on the switch itself.

Use a multimeter to check the continuity once you get it out. If it's good, you should see ~∞ resistance or an open circuit (depending on how your meter works) when the switch is popped out.

 

[miroteknik]

Here is a picture of what the light looks like when I press the button to turn it on or off (it is in the "off" position in the picture). The picture is obviously taken at night, and the headlights are turned on, providing backlighting to the console. In the picture you will see that the fan speed is in the "on" position, at a low speed. The green A/C light remains on even when I turn the fan speed selector to the "off" position. Even though it is not pictured, the defrost button (below the hazard lights button) is not pressed or lit up, so to my knowledge, the defrost function is not on. The green light is always on, as long as the motor is running.

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I will check the switch with a multimeter next week. I may be getting ahead of myself, but f the switch is NOT to blame, could it by any chance be an issue with the ECU? Thanks again!

 

[DSM1G90]

Unplug the compressor's clutch selenoid, which is the twin wires going towards the clutch assembly. There is a connection there.

OR, unplug the fuse in the fusebox that runs the AC.

 

[miguelmcv]

No, the ECU has nothing to do with the AC, There is an extra ECU for the AC, It's just a little back box like the Cruise control.

Was wondering, Is your Fan ON, or is just the AC compressor ON, Can you manipulate the Fan, can you shot off the fan?.

 

[DSM1G90]

Put a small screwdriver behind the button's outer edge, wedge it a bit and the assembly pops out.

Un plug the connector from the back of the button assembly.

These switches can get stuck after age. You can go out to a yard and grab another one for cheap.

 

[miroteknik]

Unplug the compressor's clutch selenoid, which is the twin wires going towards the clutch assembly. There is a connection there.

OR, unplug the fuse in the fusebox that runs the AC.

No, the ECU has nothing to do with the AC, There is an extra ECU for the AC, It's just a little back box like the Cruise control.

Was wondering, Is your Fan ON, or is just the AC compressor ON, Can you manipulate the Fan, can you shot off the fan?.

Put a small screwdriver behind the button's outer edge, wedge it a bit and the assembly pops out.

Un plug the connector from the back of the button assembly.

These switches can get stuck after age. You can go out to a yard and grab another one for cheap.

@miguelmcv, I can shut off the blower if that is what you were talking about. It does not blow when I put the selector in the "off" position. I am strictly chasing the issue of the green light always being on and the A/C compressor always running. The fans are not the issue.

Thanks again guys! I ended up pulling both the fuse and the relay pictured (below), and the A/C compressor of course shut off, but the light in the button still was on whether it was pressed in or popped out. This makes it sound more and more like the button is bad. I tried using a small screwdriver from a glasses repair kit to remove the button like DSM1G90 suggested, but could not get it to come out. Do I need to remove the plastic console cover or is it supposed to pop out without removing any of that? I didn't force it too hard cause I didn't want to break anything, but I ended up scratching the button up anyway .

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[miroteknik]

Finally got the A/C button out, unplugged it, but the A/C compressor would still run (with the fuse and relay back in). What else could it be?

 

[miguelmcv]

Your ECM is bad or you have an open wire some where, Look for the ECM and unplug it to see what it does, If it still turns ON, then that's an open wire that you have on the line.

If it doe stays ON with the ECM unplugged, then remove the pressure switch, located on the AC lines at the engine bay, if removing it turns OFF the compressor, then the open wire is between the switch and ECM, but, If it doesn't turn OFF, then, the open wire is between the pressure switch and the compressor.

Here is the manual of your car, check from page 230 to 250, that's the M/t and A/t, check the chemistry so you have a better knowledge of the system.

http://www.scribd.com/doc/17887698/9799EL

Forgot to ask, Is your car M/T or A/T?.

Let us know what you find.

 

[DSM1G90]

I blame it, then, on a relay that has stuck closed to keep the compressor running if the OP removed and unplugged the switch.

 

[Number1dad]

Did you resolve your problem, with this cold weather who needs a/c

 

[miroteknik]

Your ECM is bad or you have an open wire some where, Look for the ECM and unplug it to see what it does, If it still turns ON, then that's an open wire that you have on the line.

If it doe stays ON with the ECM unplugged, then remove the pressure switch, located on the AC lines at the engine bay, if removing it turns OFF the compressor, then the open wire is between the switch and ECM, but, If it doesn't turn OFF, then, the open wire is between the pressure switch and the compressor.

Here is the manual of your car, check from page 230 to 250, that's the M/t and A/t, check the chemistry so you have a better knowledge of the system.

97-99EL

Forgot to ask, Is your car M/T or A/T?.

Let us know what you find.

I blame it, then, on a relay that has stuck closed to keep the compressor running if the OP removed and unplugged the switch.

Did you resolve your problem, with this cold weather who needs a/c

I purchased a used ECM and installed it this weekend. It resolved an issue I was having with the electric radiator fans, but it did not resolve my A/C issue. I am trying to find a new A/C button, hopefully I can find one locally.

@miguelmcv, thank you for all of the info! The car is a manual. If the new button does not fix my issue, I will definitely use your tips to find the open wire. When you said to unplug the ECM, did you mean the engine computer, or did you mean the A/C control box?

@DSM1G90, I will keep that in mind, thanks.

@Number1dad, I do not need A/C now, but I will need it in the summer. Why wait till summer to fix it, if I have time to fix it now? Plus, I hate having a car with this and that broken or malfunctioning.

 

[miroteknik]

Got the new button and installed it. That did not fix my issue, the green light on the A/C button is still always on, and I cannot get it to shut off. I do not know what to do now. Where should I be looking for a short or open wire? Thanks.

 

[miroteknik]

bump

 

[Diamond Star Werks]

Unplug the a/c and see if it goes away.

 

[luv2rallye]

Sounds like you may have multiple problems (possible AC ECM stuck on, AC compressor relay stuck, short, etc). But one thing that doesn't sound right is the AC green light should only get power when the blower switch is in the not-off position. This switch has a known failure of that part of it going bad producing various strange results. You also stated the green light stays on even with the blower switch off which points to it. So unplug the blower switch and if the light goes off you at least have a bad blower switch (may still have other problems too but I'd start there).

 

[miroteknik]

Sounds like you may have multiple problems (possible AC ECM stuck on, AC compressor relay stuck, short, etc). But one thing that doesn't sound right is the AC green light should only get power when the blower switch is in the not-off position. This switch has a known failure of that part of it going bad producing various strange results. You also stated the green light stays on even with the blower switch off which points to it. So unplug the blower switch and if the light goes off you at least have a bad blower switch (may still have other problems too but I'd start there).

Thank you!! I'll check that out!