Hey, so the a/c in my accord started blowing hot recently... And I don't know enough about the system to know how to diagnose the problem. If this helps, the cooling fans both appear to be working, and the top hose coming from the radiator is hot when the engine warms up. Cooling system is free of air bubbles.

What steps could I take to get this figured out? How do I check if Freon is low or if the compressor isn't working properly?

 

If you don't have a/c guages, to get an accurate diagnosis take it to a shop.

 

not sure the relation between the coolant level and your A/C system...

 

if you dont have continuity at the ac pressure switch then you have a leak which caused your freon to leak out

 

When I test continuity, should the multimeter beep continuously with no breaks, or is it normal to sort of beep on and off?

 

I thought having air in the system might cause the cooling fans to not function properly due to reading the temp wrong. What do I know lol

 

if you have a beep setting then it should beep if there is continuity

 

solid reasoning based on your assumptions. however (to my knowledge) the condenser fan (if not both) can be triggered independently of the radiator fan.

Some things you can do before having the pros check it are:

-look for signs of leakage (grime emanating from joints in the system, damp oil residue possibly with neon green/yellow dye)
-confirm the compressor fan (driver's side) comes on and the compressor clutch engages (face of the pulley spins) with engine running and A/C on full.
-didn't catch the year/trim level but if you have manual vent adjustment try finding the cable under the dash that controls the blend door (transitions from heat from the heater core to cooling air from the evaporator) and make sure it doesn't appear to have slipped from it's clamp.

 

Right, but it beeps on and off, sometimes the beep lasts for half a second, sometimes it lasts for a couple second... Is that normal or should the beep be continuous (unbroken)?

To the above poster, the year/trim is in my Sig, sry. '94 lx. Thanks for the suggestions, I'll check it out tomorrow.

 

geez dude this isn't rocket science. When it beeps that means that there is continuity ... if it goes on and off that's probably because your clips are coming off the pins of the switch

click the multimeter together, it will beep.. if they touch the tips of the switch and it beeps that means that there is enough freon in the system

however you could just be pushing the tips of the multimeter together inside the switch instead of hitting the pins of the connector so just be sure

 

Just to add/correct a bit - BOTH fans should come on if the AC is on/working.

If both cooling fans come on when you press the AC button (key on/pos II and the blower motor on) - there is enough charge in the system for it to "try to run".

So if this is true - both fans come on when the AC button is pressed and the AC compressor clutch engages - as stated the charge is low (does the ac cycle on and of pretty quickly?). Or there is an issue with the blend door/heater control valve.

EDIT: Just to add a bit - on any 4th or 5th gen Accords - anytime the "key is on" and conditions are met (temp from thermo a or a signal from the ECU that the AC is running) BOTH fans run. When the key is off is the ONLY time one fan runs.

 

yes, thanks for the correction.

 

Its cool, I get confused all of the time

Kimi didn't fair too well this morning

 

Ok, so I derped a little bit... I thought i heard both fans clicking on, but upon visual inspection the condenser fan wasnt going on when I turned on the a/c. I changed the 15a fuse and now the a/c works but it's not as cold as it should be.

I think the valve that controls the transition from heating to a/c is stuck open so the heating system is fighting the a/c... But I'm having trouble locating the cable that I would need to adjust so the temp dial will close the valve fully. There is nothing on the a/c system in my Chilton manual... It just says DIYers shouldn't mess with it and should take it to a shop.

If tinkering with the cable doesn't help, I'll look into getting the system checked for leaks, evacuated, and recharged. But for now I'd like to explore the "blend door/valve" possibility first. Can anyone point me to a DIY for adjusting the cable or even just point me to the location of the lever so I can manually close it fully to see if the a/c blows colder?

 

Pop the cable off the heater control valve, "just pass side center" of the firewall. There is a little "fold over clamp" that holds the outer part of the cable, undo that and the slide the eyelet of the cable off the valve. Manually close the valve, see what you have?

Sometimes the valve can fail internally, meaning the lever "says it is closed" but coolant is still flowing thru, so feel the inlet hose vs the outlet - it is kind of a feel thing becasue there will be some natural heat transfer from the hose/valve inlet to the outlet.

Do a search on "blend door adjustment" and you should find plenty of info on how the two cables work.

 

This is probably a dumb question, but is the cable/valve on the firewall in the engine compartment or under the passenger side dash in the cabin?

 

make sure coolant is topped off. also make sure that the temp is normal if it gets to hot the thermal switch which works with the a/c as well it will turn it off to prevent car from overheating i know im going to get flammed for saying that but its true.

 

Temp is fine, it hasn't ever gone above the halfway mark on the gauge. Cooling system is full and bled of air bubbles

 

the actual valve is at the firewall

 

Update: I got everything fixed and the a/c was running ice cold for a couple weeks. Then today, it was warm again out of nowhere. I checked the fuse and the same one had blown again after only 2 weeks. What would cause the same fuse to blow out so soon? Can I check certain spots in the circuit with a multimeter to diagnose the problem or is there an obvious culprit I should replace?