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If my AC works fine at the start of the drive, and then doesn't work at all, could it be low on refrigerant?

With my 07 Odyssey, the AC will work fine (with nice cold air coming out) when the car is first started and will work for maybe 5 minutes or so. Then just warm air comes out of the vents. When the air turns warm, the compressor does not go on when the AC is on. Same thing happens whether the blower fan is on high or low.

I called repair shops, and they want about $100 to test it and said it may just need more 134a refrigerant. But if that was the case, wouldn’t the loss of cold air been more gradual and permanent? Now it works fine for the first few minutes with nice cold air, and then quits working for the rest of the ride.

I was worried it was the compressor going out, and one shop said that would be about $900 to repair.

If it could be lack of refrigerant causing the problem, I’ll probably try to do a DIY recharge to see if that solves it before spending a minimum of $100 on repairs.

Thanks for any advice you may have!

I am completely against do it yourself air conditioner work. Just pay the shop the 100.00 and find out what really is wrong then decide if you want spend the money to fix it.


Before it can determine the cause of the problem, it must be determined the state of charge of the AC system with a set of manifold gauges.

Doing anything else is just guessing. And adding more refrigerant when it’s not required can damage the AC system.

The problem might be with a defective expansion valve.

And adding more refrigerant won’t fix that.


Thanks for the advice everyone. I just found this YouTube video where a guy had a similar problem with his Honda (different model though) blowing cold air at first and then going warm. He figured out it was a defective relay in the fuse box, which was a $7 fix. I’ll have to see if I can find a similar relay in my vehicle and test that.

Agree with Tester but if you are talking electrical, just determine if the compressor stops or not when you develop warm air. If it stops, then it could be electrical. Note though that they have a pressure valve that will shut the compressor off if the pressure is too low but usually it will run a little before that kicks in. You can do a little simple diagnostics on your part but stay away from DIY refrigerant charging, IMHO anyway.

Go the relay route FIRST. Swap out your horn relay with the AC clutch relay. That worked for me on my 2003 Odyssey when my my AC would not cycle to the real cold air! My relay cost under $10. Easiest DIY vehicle repair out there 2007 Honda Odyssey is the most PRACTICAL vehicle on the road! Good luck.

I had the same problem with a 1990 Ford Aerostar. It turned out that the fan clutch was slipping so that the fan was not pulling enough air through the condenser. Now your Odyssey probably has electric fans rather than a mechanical fan as my Aerostar had, but if the electric fan either isn’t operating or not coming up to speed, that could be the problem. My independent shop hooked the gauges onto the system and watched them while the engine idled with the AC on. The pressures suddenly went up and the AC quit cooling. The mechanic then took his big shop fan and directed the air through the condenser and radiator. The readings on the gauges immediately dropped and the system began cooling.

Hey that was the problem and it’s now fixed! On my 07 Odyssey there were three of the same relays in that box, so I swapped it with what I think is the aux. fan or something (didn’t see any of the same size for the horn). I swapped it with the top left similar one when looking at if from the front of the van. Part was $6 and both Advanced Auto Parts and O’Reilly had it in stock.

For those who have similar problems, I found several more videos on YouTube about different models of Honda with the same problem, describing basically the same fix. But if you watch the one I linked to above, that gives you a good overview.

Thanks everyone for all the advice!