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Junior Member
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Discussion Starter #1
Well I got another problem. The help I get from you guys is awesome!!

My Problem: The AC clutch does not pull in.

My AE Scan tool says the compressor is energized. I can disconnect the low pressure switch and cycle the selector switch and then the AE tool says the compressor is deenergized. Conclusion is all is ok up to the output of the computer to the AC Relay.

I have reviewed the wiring diagrams found in the 6.0 Bible in the Sticky section of this forum and determined that the relay is most likely one of 4 relays in a module on the fire wall on drivers side. The problem is I cant figure out which relay is the AC relay. I pulled all 4 relays and bench tested each one. The relays are all ok. I also found a post by Lenzhotrod with the complete AC System Troubleshooting guide. Thanks, Lenz

Before I dig down to the wiring at the clutch, I want to do a few tests from the relay socket.

So which relay is the AC Relay? See the pic.

Thanks in advance...
 

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Senior Member
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3,051 Posts
First, good to hear from you Fixinit!

I'm not sure myself which relay without a chart either, but you can just jump the terminals for power transition with any of the relays removed and it should send power to whatever the relay powers up. Circuit 30 and 87 are common jump together pins for transition of power to a consumer if the relay is marked with those numbers like some are. The relays in that box you show are for FICM, AC compressor, PCM, Fuel Pump if I remember correct.

Harry
 

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Junior Member
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Discussion Starter #3
By using process of elimination, the grey colored relay is the FICM. With all four out the fuel pump will still run when the key is on. With the FICM relay in and the other three out the engine will run.

Each relay has a good diagram printed on it. I found battery voltage on one side of the contacts as the wiring diagram indicates. (page 90 & 91 of the 6.0 Bible)

I still dont know what the two identical relays do but the one small relay is the AC relay. To prove this, I made some jumpers to fit into the coil terminals and connected the relay without plugging it into the socket. Then I hooked my ohm meter to the contacts and started the engine and turned the AC on and off at the selector switch. The contacts closed and opened in response to the selector switch thus proving the relay is good and the computer is commanding the relay.

I then measured the resistance from the clutch side of the contact to ground and I saw what I believe to be the resistance of the coil. This leads me to believe that the circuit is intact all the way thru the clutch coil to ground.

I then used a jumper wire and applied battery voltage to the clutch coil wire at the relay socket. I expected to hear the clutch click but heard nothing.

So now the fun begins... It looks like I need to remove the fan shrouds to gain better access to the AC clutch. When I get good access to the AC clutch I will energize it again with my jumper and see what happens.

I have never taken apart an AC clutch but it looks relatively simple. Does it take common tools or do I need a special puller to get the clutch off?
 

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Senior Member
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Some clutches require a special pulling tool or socket, but most you can get apart without special tools. I'm not sure how it works on our trucks, can look on alldata, but I have this next week off and won't be back into work till after the 1st.

Harry
 

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Discussion Starter #5
Thanks Harry, I haven't been on here in awhile. I have been on a few times just to read up on whats happening but haven't had the need to post anything.

I read a post awhile back that mentioned me and my problems/solutions. It was very satisfying to read a post that mentioned me. I'm glad I took the time to write up what I have been doing. I hope that it gives others the encouragement they need to fix it themselves even if they are not a trained diesel mechanic.

I was going to tear into the truck today but I will need the truck, AC working or not, this coming week so I have to let the AC repair wait a little longer. Not to mention that its 102 degrees outside today. Not the best weather for shade tree wrenching. The truck is only used occasionally now and not a daily driver.

We went camping with the trailer last weekend and all worked well (except the AC). The truck hadn't seen a good workout in a long time.
 
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Junior Member
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Discussion Starter #7
Well a lot has happened since I last posted about my AC clutch.

We went camping again on Labor day weekend and the radiator decided it was time to blow. The top tank cracked and was spewing coolant. We were only 30 miles from home so we turned around a limped home. We stopped every 5 miles and topped up the coolant. Made it home in one piece. Old radiator came out quickly. It took longer to go get the new radiator than it did to put it in. Long story short we were back on the road a few hours later. All went well except still no AC.

So today I had time to look into the AC clutch a bit further. I discovered that the front half of the AC clutch was completely missing. I guess the air gap was a little too big!

Ford wanted a bunch of money for just the parts that were missing. So I went to an after market shop and bought a complete compressor for a few dollars more. It seems everybody wants a ton of money for the parts but the whole compressor fully assembled is reasonable. Now I have a spare compressor minus the clutch.

I took the clutch assembly off the new compressor and am planning to put the new parts on the old compressor. Easier said than done.

To make room to get at the snap ring on the front of the compressor, I wanted to remove the fan and shrouds. They came off pretty easy but to get them out, the pulley that the fan bolts to needs to be unbolted from the water pump. The darn bolts are stuck and I cant get them off. I sacrificed a 10mm box wrench and cut off the open end and used an 18in long 1/2in galvanized pipe as a cheater bar. The bolt nearly stripped off. I gave up and will probably grind off the bolt heads and then have to remove the water pump to get the bolts out. Unless anybody has any suggestions on how to get the 4 bolts out or the snap ring on the compressor without removing the shrouds.
 

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Old Fart
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889 Posts
You can cut off the top of the fan shroud. There are a couple of tabs that will allow you to fasten it back together. I would use duct tape also.
 

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Discussion Starter #9
Cutting off the shroud and making it a two piece sounds like it might be a good idea. Where exactly do you propose the cuts? Have you done this before? Do you have some pics? I'm not real keen on just hacking away with a sawz-all.

I would have had it out already if the 4 bolts to the water pump hub would come loose.
 

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Old Fart
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889 Posts
I have an 04 model and no I have not hacked mine. There are lines on each side about 4 inches below the top. Go look for them, they should be there.
 

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Discussion Starter #13
That is a good video on how to R&R the radiator. That's what I did last week. The job was real easy.

My problem now is how to get to the snap ring on the front of the AC compressor. The fan and shrouds are in the way, or so I think.
 

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Discussion Starter #14
Well its fixed!!!


After much trial and error, I finally figured out that the fan shaft is threaded onto the water pump. I had to buy a big wrench and smack it with a hammer. It spun loose pretty easy. I initially thought the four bolts on the front of the water pump needed to come loose to get the fan out. I was wrong. The pulley can stay in place and the fan unthreads from the water pump shaft.

I then got the snap ring loose on the front of the AC compressor. Removed and replaced the clutch assembly and since I had the whole front of the engine exposed, I put in a new belt just because. I then test ran the AC before putting the fan back in. With my luck, I would have gotten it all back together and then something else would have been busted. AC now makes 43 degrees at idle. That's good enough for me. I don't think it ever got colder than that.
 
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