A/C does not cool, one of two fans down, relays okay
 

Hi all,

TSX 2004. My A/C does not cool anymore and the Texas heat is coming soon. The cabin fans are okay, A/C blows the outside air through without cooling it. I can hear the compressor click and engage when I turn A/C on.

One of the radiator fans, driver side, is not working. I opened the fuse box and swapped all black and blue/green relays and the driver side fan is still off. Is the stopped fan the cause or a symptom of a problem? What other diagnostics I can do?

thanks,
Sergey

I believe there is a sight glass on the receiver/drier (from memory, not sure). If so, observe the sight glass when the compressor is running.

If it runs pretty clear w/ just a few bubbles, then cooling should be OK. If not, air is also passing over heater core re-warming cooled air. Heater blend door problem.

If lots of foamy flow or no flow, something is wrong w/ AC charge (may be partially lost). foamy flow likely indicates a leak somewhere causing low charge and low cooling.

If no flow, compressor must not be running as low pressure switch will prevent compressor from running w/ too low refrigerant.

good luck

Thanks. I checked the glass, I see clear fluid going through when the compressor kicks in. Any other ideas? Both fans on the radiator should be running when A/C is on, correct? Why would only one fan run?

Well the drivers fan is the radiator fan, the passenger fan is the A/C condenser fan. Even so, a stopped radiator fan is a fix now in Texas.

For an '04 Radiator Fan, troubleshoot by:

1) Check #11 fuse (20A) under-hood and #30 fuse (7.5A) under-dash

2) Check radiator fan relay (under-hood box)...probably about $10-20 bucks, may as well replace it...but the check is no continuity between #1 and #2 terminals on the relay with no power, with power and ground on #3 and #4 there should be continuity between #1 and #2.

3) Voltage between fan relay socket #2 and ground (should be battery voltage)

4) Jump fan relay #1 and #2 sockets. What does the fan do?

Report back results and we'll dig further...the possibilities are the fan motor, open wires, and a bad switch.

Inop cooling fan is not the reason for lack of AC. Check fuse 11 in underhood fuse box. Suggest pulling connector to radiator fan and checking for 12V w/ AC commanded on. If 12V, fan is bad (likely). If not 12V, the relay or fuse (#11 underhood).

Any cooling when engine is started cold. If yes, then no AC when warm suggests the heater core valve may be stuck open. It's operated by a cable and should move to open position for heat and closed position for cooling.

Check AC suction line (returns from evaporator to compressor) at the firewall. It should be quite cool if AC is working correctly.

good luck

Thanks, guys! Silly me, I have read somewhere that both fans should be on when A/C is on and that was misinformation. Now I understand that my condenser fan is on when A/C is on, that's good news. And actually when I stick a bright flashlight to the sight glass I can see fluid coming through with a lot of bubbles. It's not foam it is definitely grain-sized bubbles of air. Also I hear a hissing sound from behind the dash when A/C is on. Should I have refrigerant added now or remove the dash and look for air leaks first?

thanks again!
Sergey

And the suction line is a little bit cooler than other metal parts under the hood but not by much

Sergey

Yes, low charge is very likely. Do you have a set of AC manifold gauges and charge equipment? If not, time to get some help.

I would suggest having a leak inspection before recharging. You may find a leaking compressor, damaged condensor, or leaking connection or hose.

A leak allowed charge to decline. It could be a small leak, or perhaps large leak that recently started.

good luck