Same thing has happened to me on two other cars, which is as the car ages the clutch gap widens, and when hot, the gap is too wide for magnetic field to pull the clutch in.

As clutch cools, the clutch engages as normal. As it gets hotter, it's a no go.

Two things, and with car running and AC on, and clutch not engaging:

1. Goose the clutch with a large screw driver. It should pull in.

2. Check for 12 volts at the clutch connector.

Clutch gap can be adjusted by removing on of its gap spacer washers. Cost is $0.00, and nothing beats $0.00.

Check youtube.

 

Wait a minute or so before you goose the clutch.

 

... I didnt overcharge it!

How do you know this? If it was not low on refrigerant and you added some then it will be overcharged. The only way to properly charge an auto AC system is to remove/recover the refrigerant, put a vacuum on the system for about 30 minutes, then add the exact right amount of refrigerant. "Adding a little freon" will overcharge it if it was charged properly to begin with.

The first thing I'd check is your radiator fan fuses. There are two 30A fuses in the underhood fuse box that control the radiator fan (driver side fan) and the condenser fan (passenger side fan.) These fans do not work as you would expect. When the AC is off the fans will cycle on and off of low speed based on coolant temperature. They both run off the condenser fan power and relay. When the AC kicks on, and the pressure in the AC system hits 221PSI, then BOTH fans should kick on to HIGH speed. In high speed mode they each use their own power and relay. So, even if the radiator fan fuse is blown the radiator fan will still run on low speed but not on high speed and that can cause high pressures in the AC system, possibly enough to kick the system off due to high pressure.

Check those fan fuses first.

 

I think it may be a fan fuse issue. And it's possible I overcharged the system. I got a AC pressure guage to get a better feel for what's happening in the system. Here's what I found...

For the first 3 minutes (when the AC is on initially) the low pressure side comes down to and stays steady at 41 psi. The high pressure side rises steadily the entire time all the way to 475 psi! And that's when the system shuts off. Exactly as John Clark described.

Also, i didnt mention this originally (because i wasnt sure what to make of it), but the passenger side fan never turns on. The drivers side fan is the only one that runs when the compressor is engaged. Again this is exactly what John Clark described above. I am going to check the fan fuses and see what's going on there. Thanks for the help! Will update with what i find out, and any more input based on these details is welcome.

 

I've got a set of gauges and while they do help troubleshoot, remember that they don't really provide a good indication of proper system charge. I found my fan problem when I saw my pressures too high but I could have easily found the fan problem without that just by looking. Like you, I wasn't expecting a fan problem but that's what I found. Fortunately, I didn't add or remove any refrigerant before finding the fans not working properly. Once both fans were working properly the system was in the normal range.

I'm learning about gauge use on my old 1998 Nissan 200SX. I've tried to get the system charge just right by using the gauges and it's just not possible. I can't tell whether I'm under charged or over charged, and either will give the similar results on air temperature inside the car. My next AC tool will be a vacuum pump but even with that I still can't recover the refrigerant that's already in a system. If the system is empty I could then put a vacuum on it and then put in just the right amount of refrigerant (as shown on the sticker under the hood) and then check the system and the pressures.

 

Well bummer. I checked the fuses and they are both good. Both 30A fuses are fine. Was really hoping that was it...would've been an easy fix. So now what do i check to try and get the passenger fan working?

 

Start with swapping the relays. In that same fuse box under the hood there are two black relays on the top row, closest to the firewall. The one on the left should be the radiator fan relay and the one on the right should be the Condenser fan relay. They are the same relay so swap them and see if anything changes.

If that doesn't change anything, see if you can unplug the condenser fan and run 12 volts to it to see if it will run. Most likely it's either a problem with the relay or a problem with the fan.

 

Thank you John Clark. I am getting closer and closer to discovering the problem. It is definitely a fan issue. However i dont think it's the fan or the relays. Here's what i've done so far...

I disconnected the non-working passenger fan, then used my multimeter to check and see if there was any voltage coming in when the van was on with AC and drivers side fan on. Nothing. Then I disconnected the drivers side fan and checked it the same way. 14 volts. Then I ran 12 volts to the passenger fan, and it turned on and worked well. Then i started the van with the 12 volts still running to passenger fan. Everything worked! With both fans running the AC worked and stayed on, and the pressure was steady (low side stayed at around 32psi and high side stayed around 205psi).

After disconnecting the manual 12V to the passenger fan and reconnected the fan to the van's electrical system... I switched the relays, no luck there. Same problem. Passenger fan stays off while drivers fan turns on...and AC high side pressure steadily rises. I even switched it with the 3rd black relay in the front of the fuse box. Switched them all in every possible configuration with the 3 relays. No luck.

So now i have to figure out why the van is not telling the passenger side fan to turn on when the AC is on. Anyone have any thoughts here?

 

The third black relay in the front is the relay for the compressor clutch so if the compressor still kicked in with the other relays then the relays are probably working.

One important question...If the AC is off and you let the engine idle and get hot, do both fans cycle on and off on low speed?

You should have checked fuse #11 and #9 in the underhood fuse block. Now check fuse #30 (10A) in the drivers kick panel as that fuse powers the control side of the condenser fan relay just to make sure it's good--it probably is. There is a third relay involved here called the fan control relay and it is down below the power steering reservoir. It's a 5 pin relay. We are missing either power or ground (or both) to the condenser fan. Here's how we can check to see which is the problem:

Start the engine and turn the AC on. Then go to the non-working condenser fan and unplug it. Attach the black wire of your multi-meter to ground and then use the red probe to check the Blue/Yellow wire on the harness coming in to the fan (not the harness going to the fan.) Are you getting +12V on it? If so, that means the condenser fan relay is working and supplying power.

Now, disconnect your multi-meter and connect the red probe to the positive side of the battery and the black probe to the white/red wire on the harness coming in to the fan. Do you get +12V? If so, that means the fan control relay (down under the PS reservoir) is providing the ground for the condenser fan.

If you're missing the power on the blue/yellow wire but have the ground on the white/red wire then the problem lies in the condenser fan relay circuit. If you're missing the ground on the white/red wire, or the power and the ground both, then it's most likely the fan control relay.

Let me know how those checks go and we'll go from there.

 

Did you ever check for 12 volts at the clutch?

Does the on/off cycling also occur when you're out on the highway, as when you're out driving at a steady 60, you don't need fans.

 

There has to be 12 volts at the clutch in order for the AC to come on and the pressures to go up, which is what he's experiencing. He's definitely got a fan issue that needs to get sorted first and then see what the system does after that.

 

Not to beat a dead horse, but if there is 12 volts at the clutch and the clutch is not engaging/reengaging, it may very well be because the gap is too wide. As the clutch cools, it can then engage. I've had this exact problem on two of my cars, but I'm not saying this is the OP's problem. It is, however, part of the troubleshooting process.

 

John Clark... I checked the fuses including the one in the driver's kick panel. All good there. I had already checked to see if we were getting power from the harness coming to the non-working fan. Checked again tho...still no power there. Then I checked to see if it was grounded by connecting the red probe of my multimeter to the positive side of the battery and the black probe to the red/white wire. No power there either. So based on what you said, it looks like it's the fan control relay then?

I took it one step further than your instruction though and found something interesting. I connected the red probe of my multimeter to the blue/yellow side of the harness going to the fan and connected the black probe of the multimeter to the negative side of the battery. And i got 14V. That tells me the van is sending power to the fan, but the ground is not set. So maybe the problem is just as simple as a disconnected ground wire somewhere?

What do you think?

 

...I took it one step further than your instruction though and found something interesting. I connected the red probe of my multimeter to the blue/yellow side of the harness going to the fan and connected the black probe of the multimeter to the negative side of the battery. And i got 14V. That tells me the van is sending power to the fan, but the ground is not set. So maybe the problem is just as simple as a disconnected ground wire somewhere?

What do you think?

This is exactly what I instructed you to do in my fourth paragraph above to check the fan control relay since the fan control relay sets the ground for the condenser fan. No matter...looks like you found the problem. Yes, your entire fan control relay assembly is missing! Someone has done a hack job on your van. If it were me I'd try to find the assembly with relays from a wrecking yard. Short of that you could probably just plug in the relay and tie the harness somewhere so it doesn't move.

How long do you suppose it's been this way? That high pressure is really hard on the AC system.

 

See the 2008-2010 Honda Odyssey Electrical Troubleshooting Manual (ETM), if you haven't done so already.

http://www.odyclub.com/forums/52-20...7171-2008-2010-honda-odyssey-electrical-troubleshooting-manual.html#post1277857

Under Indexes, select All Circuit Schematics.

In the Circuit Index, select A/C condenser fan 63. You will then have the schematics.

At the top and bottom of the schematic page, select the How the Circuit Works box.

 

Thanks EE4Life. That ETM link was very helpful.

As i was looking for the Fan Control Relay, i used the ETM to see where it's supposed to be, but it doesn't appear to be there. Instead i am seeing a connector dangling loose not connected to anything. The connector has the following 5 wire colors going into it: Black, Blue/Back, Blue/Yellow, Green, White/Red. That matches exactly with the ETM diagram shows as the wires that should be going to the Fan Control Relay. But it appears that the entire relay is gone! Going to try to insert some images of what i am seeing...

 

It looks like i need the Fan Control Relay and the bracket to hold the relay connector in place in the engine compartment. Parts 8, 17, 21, and 27 in the diagram below...

The fan control relay looks like this i assume...

Anyone confirm this? What do you think John Clark?

 

Got the High / Low Fan Control Relay and installed that two days ago. I ended up finding that the cheapest place to buy it was amazon.com. Cost me $28. I ended up passing on the other parts (bracket and cover...etc). The honda store wanted $190 for the bracket alone. Instead i wrapped it in electrical tape and used zip ties to securely fasten it under the fuse box area. Van AC is working great now!

 

Good work! Makes you wonder what happened that caused that stuff to be removed and never replaced. Was the vehicle wrecked on that side?

 

The vehicle was wrecked on that side. I bought it after it was re-built.

 

That would explain a lot!

 

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