A/C problems

[Joeteck]

Ok, guru's another question for you...

 

My AC does not turn on when I press the button or turn on the defroster. What could be the problem, and how can I fix it..??

[James Matteu]

Does the light on AC button light up?

Do you hear the compressor click on? Can you have someone toggle the button to see if there is any response under the hood?

If you're on the highway and switch on the AC, with the fresh air vent open, does the ambient air get colder?

Does your blower function? Does it blow strong? Do all fan positions function?

Do you hear any hissing in the dash after the car has been turned off?

Is there any smoke coming from the AC compressor?

Does the AC Compressor belt have sufficient tension? (stupid question, you do have a belt, right?)

Have you had the High/Low pressure measured? If so, did the test indicate that you are low on R-134a?

 

Let me know what's up.

 

Edit: could you be more specific as to how the AC problem relates to the rear windscreen defroster?

[Joeteck]

Does the light on AC button light up?

Do you hear the compressor click on? Can you have someone toggle the button to see if there is any response under the hood?

If you're on the highway and switch on the AC, with the fresh air vent open, does the ambient air get colder?

Does your blower function? Does it blow strong? Do all fan positions function?

Do you hear any hissing in the dash after the car has been turned off?

Is there any smoke coming from the AC compressor?

Does the AC Compressor belt have sufficient tension? (stupid question, you do have a belt, right?)

Have you had the High/Low pressure measured? If so, did the test indicate that you are low on R-134a?

 

Let me know what's up.

 

Edit: could you be more specific as to how the AC problem relates to the rear windscreen defroster?

 

 

1. Yes

 

2. No

 

3. Blower, yes.

 

The other questions are unknown at this time...

 

EDIT: I never said anything about the rear defroster. But just so you know, when you select defroster, the ac turns on automatically, regardless of the AC setting...

[James Matteu]

1. Does the light on AC button light up? Yes

 

2. Do you hear the compressor click on? No

 

3. Does your blower function? yes.

2. Do you hear the compressor click on? No.

But when you select defroster, the AC light comes on and you hear the compressor click on, right?

 

I need to review my Electrical Manual and get back to you this evening.

[Joeteck]

2. Do you hear the compressor click on? No.

But when you select defroster, the AC light comes on and you hear the compressor click on, right?

 

I need to review my Electrical Manual and get back to you this evening.

 

When I select defroster the AC does not click on either....

 

Someone has mentioned the freon is low, and the low presure switch is not on.

 

I was told to remove the plug to the switch and jumper it to see if the compressor does in fact go on..

 

I have yet to try this diagnostic meathod.

[James Matteu]

EDIT: I never said anything about the rear defroster. But just so you know, when you select defroster, the ac turns on automatically, regardless of the AC setting...

When I select defroster the AC does not click on either....

I am confused. Can you clarify what exactly happens when you select defroster, and just to be clear, which button are you talking about:

 

#4 below

 

Or the button on the far right in #14 below

[Sand]

clarify that up for use and we might get your problem solved.

[HONDA CRX 88 SI]

no he is right when the defroster is turn on the a/c should turn on to, so i am guessing youre problem has to be on a bad fuse or bad relay. check the diagram for your car

[James Matteu]

No, that is incorrect.

 

If the Mode Control Motor or the Air Delivery Control had anything to do with switching on the AC, there would be a ground bypass line running from the A/C Relay through the Air Delivery Control (which operates the Mode Control Motor) to the chassis; but there is not as you can see below.

 

Instead, the Air Delivery Control (where the defroster button is located) is fed voltage directly from Fuse #8 via the black/yellow wire in connection #611 (C611). In this way, the A/C and the Air Delivery Control operate independent of each other. If Honda powered the Air Delivery Control with the red/blue wire in C611, the Air Delivery Control would be able to bypass the A/C controls and possibly switch on the A/C along with the defroster. Again, this is just not how the system is designed. Check the schematics.

 

The only requirements for A/C operation are:

1. ignition key in the ignition with the car running, i.e. sufficient voltage on the circuit

2. the blower has to be operating, i.e. in positions 1 through 4, not on "Off"

3. R-134a line pressure has to be between 24 and 455 psi

4. the A/C switch has to be on/engaged/depressed/...you get the idea

5. the ambient temperature around the evaporator core has to be above 37ºF

None of the above 5 requirements involve the Mode Control Motor or the Air Delivery Control.

 

 

 

 

92

[James Matteu]

No update? What gives? Did you measure the High/Low pressure? Have you measured the resistance on the thermistor, have you checked the relay, the fuses, the grounds, the connections, the switches?!

 

How 'bout some feedback? Thanks!

 

118

[khle77]

Hi,

I have a accord SE 2002, last year the A/C was warm. Brought it in to the dealer to check for leaks. They didn't find any and recharged the a/c. Now the A/C is not too cold and makes an hissing sound that goes on and off during driving. When I turn off the engine I can still hear the hissing. Which is what you describe below. Can you tell me what's wrong with my a/c?

 

Thanks,

 

Kyle

 

Does the light on AC button light up?

Do you hear the compressor click on? Can you have someone toggle the button to see if there is any response under the hood?

If you're on the highway and switch on the AC, with the fresh air vent open, does the ambient air get colder?

Does your blower function? Does it blow strong? Do all fan positions function?

Do you hear any hissing in the dash after the car has been turned off?

Is there any smoke coming from the AC compressor?

Does the AC Compressor belt have sufficient tension? (stupid question, you do have a belt, right?)

Have you had the High/Low pressure measured? If so, did the test indicate that you are low on R-134a?

 

Let me know what's up.

 

Edit: could you be more specific as to how the AC problem relates to the rear windscreen defroster?