andrewmlin

I have a 2002 Honda Accord EX 4 Cyl. The other day, when driving on the freeway, I noticed that when I turn on the A/C, only room temperature air blows out. Since air does come out, I don't think it is the blower under the glove box. I looked under the hood and noticed that with the A/C on, A/C fan and Radiator fan both turn on, but then off very quickly (~3 seconds). The car hasn't overheated after driving distance. When I turn on the A/C, I have not seen the compressor clutch engage at all.

I'm not that experienced with troubleshooting these kinds of things, but have been doing a lot of searching on the Internet, so I've tried a few things:

1. I double-checked all controls on dash to make sure they work (fresh air/recycle button, A/C on/off, made sure temp is on coldest)

2. I checked all fuses (under hood, and next to driver/passenger side doors and they look fine)

3. I've switched the 2 fan relays in the fuse box to see if one was broken. This made no effect on the situation, so I switched them back.

Is there anything else that I can try? I would really like to at least figure out what is wrong and possibly fix it before going to the mechanic.

Thanks for any help,
Andrew

angrysmileyface

Have you checked whether or not you actually have refrigerant in the system? Low or none will prevent compressor from engaging

andrewmlin

No, I haven't checked that. Do I need special pressure gauges to do this?

tim73

Sounds low on refrigerant. To test it, remove plug from the low pressure swutch, jump in between the two terminals in the plug. If the compressor/fan come on normally and run, it's low on refrigerant.

andrewmlin

Got it, thanks Tim. Yes, I tried the paperclip and the fans/compressor did indeed come on.

If I use a recharge kit to add refrigerant, do I need to remove the old refrigerant first? Otherwise, how do I know how much I still have left in the system?

tim73

Only if it is totally discharged and is atmospheric pressure. If it has some pressure, then just add what you need. To do it right, you need to have a set of gauges. If you only have the low pressure side...try to get it between 25-30psi.

andrewmlin

Got it. I'm thinking of going and buying a set of gauges. If I have a high side gauge as well, what should that read?

Thanks Tim!

tim73

When you hook up your gauges...make sure you vent air out of the lines. Then the high pressure side will really depend on the air temp. If it is cool outside...you may only read 100-120ish...but if it is a nice hot day...you can read 200-225ish.

thefew

andrewmlin you most likely have a leak in your A/C system. When the pressure drops below a certain threshold (don't ask me what it is because I am doing this from memory) there is a sensor/switch in your A/C system that prevents your A/C clutch from engaging. This protects your compressor from being damaged by low pressure. There are several places a leak can occur. The more common things to check are the valve stems on your low and high pressure side. Try and tighten them up with a valve stem tool. If they are loose you have found one or more leaks. Don't stop there though because there could be several other problems. The pressure switch I mentioned can (and did on my 1991 Accord) develop a leak as well. I did not find the leak in the pressure switch until I pulled a vacuum on the system. Unplug the switch and put your finger on the sensor. If the vacuum pump is tugging on your finger the switch has a leak. I also had a leak in my condenser, and I bought a new one. If it was my car I would borrow a set of A/C manifold gauges and a vacuum pump from my local auto parts store and see if there is any pressure in the system with the gauges. If there is little or no pressure hook up the vacuum pump and hunt for other leaks. They can be a bummer to find...I also have borrowed bad manifold gauges and vacuum pumps from an unnamed auto parts store (their initials are Autozone) so keep that in mind too! You also need to pop ALL your line connectors and replace the o-rings. R134a o-rings are green and your local auto parts store will stock them. Other parts to replace if you have a discharged system are your (1) expansion valve (under the dash attached to the evaporator on my car...not sure about yours). Pulling the evaporator and cleaning the cooling fins will pay big dividends too. (2) Your receiver-drier. Put the receiver-drier in after you have fixed all the leaks, and right before you vacuum out the system to charge it up. Hope this helps. There are videos on you tube that can help if this is all new to you. Stick with it and you will save a ton of money on labor costs...Good luck.