A/C works intermittently

Tiny
DANIEL6219
  • MEMBER
  • 1999 HONDA ACCORD
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 227,000 MILES
Hi all, yesterday my A/C quit working, the blower fan works and heat control works, but of the climate control lights quit working. Now this morning, everything worked as it should for about a half hour, then, same thing. A/C doesn't work, climate lights went out but blower fan and heat control work fine. The fuses all seem fine. I am not super handy with cars, but know enough to be dangerous.
Friday, July 30th, 2021 AT 11:12 AM

3 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,758 POSTS
Hi,

That could be a couple of things. Since the system starts working again, it doesn't sound like a fuse.

There is an evaporator temperature sensor. The evaporator temperature sensor is located on the evaporator housing. If the temperature at the evaporator gets too cold, the evaporator temperature sensor sends a signal to the climate control unit to turn off the A/C compressor clutch. This prevents condensation from freezing on the evaporator fins and blocking air delivery into the passenger compartment. This could be happening.

Tell me, when you run the A/C, do you keep it on recirculate or do you change it to fresh air once the vehicle is cooled off?

There is also a compressor clutch relay that could be failing. This relay is located in the underhood fuse box. I attached a pic below indicating which relay to check. If there is another relay with the same part number, switch them. If there isn't, here is a link that explains how to test a relay:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

The next time you use the A/C, make sure to keep it off the max cool setting and make sure it is getting fresh air and not recirculated air. See if that makes a difference. In the recirculate position, the evaporator has more of a chance to freeze up and the sensor to shut things down until it warms up.

Let me know what you find or if you have other questions.

Take care,

Joe

See pic below.
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Friday, July 30th, 2021 AT 9:13 PM
Tiny
DANIEL6219
  • MEMBER
  • 2 POSTS
I do keep it on recirculation. Where is the evaporator housing located? I will leave the recirculation off and see how that works. Thank you for your help.
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Saturday, July 31st, 2021 AT 7:11 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 109,758 POSTS
Hi,

First, you are very welcome. I just hope I can help.

As far as the evaporator, it is located behind the glove box in the HVAC box. The evaporator temperature sensor is in the same location.

If you look at the attached pic, letter A is the temp sensor and letter B is the evaporator.

Let me know if not using recirculate made any difference.

Take care,

Joe

See pic below.
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Saturday, July 31st, 2021 AT 8:03 PM

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