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Discussion Starter #1
(Sorry if this is the wrong section) So I'm just finding one problem after another on this car. I've got a 2006 fg2 si and I'm having problem with the ac.

This all started when I was having a horrible grinding type noise from the serpentine belt system. It turned out that the pulley on the ac compressor had completely locked up and was burning the belt.

Went to fix it and noticed that there was switch and wire connected from the negative terminal of the battery
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To one of the wires on the compressor.
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I didn't really give it any mind, the owner before had done some stupid stuff to the car.

I replaced the compressor and saw that the only one was full of metal. I flushed out the system and recharged it and it was okay for a day or so. Then the clutch on the compressor stopped engaging and I ended up replacing anything that had metal in it which ended up being the compressor, condenser and drier.

Less than 10 minutes after I get the car running with ice cold ac, the clutch on the compressor disengages and wont kick back in. I've checked the relay for the ac and coincidentally replaced the ac control unit (got it with a used radio) and it doesnt change anything.

Now I'm here to y'all, I've looked on the form and YouTube to no avail. Do any of you guys have any idea what I could do to troubleshoot this?
 

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Discussion Starter #2
Update: I checked fuse #20 in the under hood fuse box and saw that the fuse had blown. I replaced the fuse and now the clutch is moving, but its moving somewhat slowly and is very noisy.
 

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So, you mean that you had metal shavings in the lines where the freon flows? If so, I'd guess that the old compressor pretty much chewed itself up and send debris through the whole system. You said you replaced the compressor and then had to replace other parts that had metal in them.

I'm concerned that you didn't get all the metal out, and it has now damaged your new compressor. It is having a hard time turning, and that may be what blew your fuse and why it appears to be running slowly.

Here is my guess. The previous owner bypassed the thermal protection switch that is in the compressor by grounding it out. He/she then probably continued to use the A/C, and it started to seize and send debris through the system.

I'd say that you will likely need to thoroughly clean the evaporator, condensor, all the lines, and put in a new receiver/drier. And if debris is present again, you are probably looking at a new compressor also.

Maybe get a complete system from a salvage yard? I'm afraid you are in for a lot of work. Debris on the freon side is bad, bad news.

Good luck.
 

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Discussion Starter #4 (Edited)
We seemingly got all the metal out of the system when we flushed out all the lines and parts. I've replaced the compressor twice and got a condenser drier combo.

After replacing the fuse, I let the car sit overnight and checked the ac this morning and the ac was blowing cold like it did after we replaced everything and the clutch was moving.

This may be a stupid question, but if the owner is bypassing the thermal protection switch inside the compressor, wouldnt the new compressor have a new protection switch inside? The switch connected to the battery and compressor turns the clutch off and if the ac isnt blowing it turns the radiator fans off as well.
 

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Yes, the new compressor should have a good protection switch so the bypass or whatever they were trying to do isn't needed. Hard telling what they were thinking.

Any chance you overcharged the system? That can also cause the compressor to work too hard.

I wasn't sure if you could be 100% sure to get all the metal out.

Hope it continues to work!
 

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Discussion Starter #6
I didn't charge it up myself, an independent mechanic did it since he had the tools to do so and I trust that he didnt charge it up too much.

I'm hoping we got most of the metal out, the civics at the pick a part places around me get parted out so quick so I was hoping to not have to replace much.

My thing is, I'm not sure what the switch is for. Even with the good fuse and new compressor, if you turn the switch off it disengages the clutch on the compressor. Since it's just grounding out the compressor I'm okay with keeping the switch if I need to, the only problem is the previous owner has done a lot to the wiring and electronics of the car and I'm not 100% confident that the fuse wont blow again because of something I'm not seeing.

I'm hoping that this all was just a series of things that just happen to go wrong around the same time instead of some underlying thing going wrong. Thanks for your help with this, I really appreciate it.
 

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Your wasting your time and money if you haven’t replaced the expansion valve after all that carnage. It’s not a timid repair but will ensure proper operation. Old one likely plugged and that can cause pressure to rise and system will stop like your reporting.

AC is not easy to get right. It’s a system that has to work in harmony. Fixing only partially is a recipe for disaster.


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Discussion Starter #8
Thanks for the heads up. I've read around that to do it right I'd have to pretty much replace everything including the expansion valve but I'm trying not to spend more money than I absolutely have to. I want to say I've already gotten upwards of 4-5 grand worth of replacement parts and repairs done on this car and it's 4-5 thousand more than I was hoping to spend. Perks of not seeing the car before it's in your hands. :rolleyes:

If it so happens that the ac fails again and I have to replace another part I'm okay with that. Time isn't really a concern right now since I'm stuck at home with Covid 19 until May 15th at the earliest. Now that I've done it once I can do it again in a day if I need to. I've got a warranty on all of the parts I've replaced so far so if it turns out they stop working again I can just send them back to the parts stop for a core change and get a new one for free.

I really appreciate all the help and concern don't take it the wrong way, I'm just being a cheap sob who would rather put in more work than money.
 

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Believe me I’m all about saving money but unfortunately you will spend more money if you don’t do it right up front.

You might be ok with your existing compress but I’d flush it and drain the PAG oil then refill with fresh PAG oil.

The condenser if it’s had crap run through it needs to be replaced. Dryer filter for sure. These have very small channels and metal can find lots of hiding surfaces IMHO it’s not worth saving as you can get replacements fairly low $$$.

Next you will need to flush all hoses and lines. Yes you need to use purpose built AC flush.

Expansion valve and evaporator. Replace expansion valve and clean evaporator with proper flush. Consider replacing if it’s got grey oil lining inner surfaces. They grey is microscopic metal and will ruin all your new parts unless it’s properly cleaned and flushed or replaced.

Replace all o rings when you take things apart. Use PAG oil on o-rings for lubricant. Good idea to replace schrader valves. Make sure you have correct amount of PAG oil for all components replaced. Look up as it’s available online.

Once you have it all back together then pull a vacuum for minimum of 30 minutes. Close valves and verify it can hold the vacuum. Bleed Freon from charge line so you don’t incorporate air. Then allow freon into system. One full can then verify amount extra you need to add. My LX required max of 15.5oz or so. I used a small scale to measure my second can to judge amount going in. Obviously need compressor on for the fill operation.

Pressures will be dependent on outside air temp. In spring and cool weather don’t expect high pressures. The volume of charge is critical. Don’t just add Freon till you achieve some magic number

BTW if you go for low dollar parts only expect about a year or so of good service. A good compressor is critical. I put in a Denso and it’s been performing well. You can soon see why pros that do the proper job are expensive. Unfortunately there are shops out there that use cheap parts and cut corners for premium prices.

Sent from my iPhone using Tapatalk
 

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Discussion Starter #10
We replaced the compressor and replaced the condenser with a condenser drier combo after completely flushing the ac lines and all with ac flusher. When we flushed the system out after a few seconds there was no sign of the grey metal shavings. We also oiled everything as we put it all back together.

All the parts I've bought have a warranty on them so if they do fail again or theres still metal in them and they get clogged up I can do a core charge and get a new one at no charge. If I need to end up replacing the whole system to get this all to work the only cost to me will be the cost of the parts that havent already been replaced.

As for charging the system back up the independent mechanic I've been getting to help me made sure to get the right amount of freon for the car as well as pull a vaccum for a while and made sure it held.

The problem with the system now is figuring out why it needs that switch wired to it and the negative in order to work. The previous owner has done a number to the electronics of the car (mismatch fuses, cut into the wiring of the radio for subs, installed after market battery cables and more) and it seems like the ac failing stemmed from whatever has been done electronically to it. That or it just so happened to all fail when it did by chance. But either way I'm going to leave the system as it is unless it stops working again or I can figure out what's up with the switch.

If anything happens I'll update you guys. Again, thank y'all for your help!
 

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Perhaps the wire/switch was a workaround for a break in the engine wiring harness somewhere. If you use a wiring diagram, you could check what wire they connected to and then check the wire for continuity. It could just be that instead of tracing down where the wire in the wiring harness was broken, they just added another wire. Not sure about the switch, though.

Is it possible to send a picture of the end of the connector that they modified? Might be able to identify which wire they are grounding out. Does it have three wires, all in a row? And this plugs into the clutch or into the pressure sensor?

It does sound like you may have learned a lesson about never buying a car without seeing it first. Anytime I see a car where the owner has been doing a bunch of shoddy DYI repairs, I walk. Too many other cars out there without asking for issues. But hindsight is always better and look at it this way - you've learned a ton about your car.
 

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Discussion Starter #12
That's exactly right. It wasnt my choice to buy the car without looking at it sadly. My parents showed me to listing for the car, I liked it and they went and checked out the car while I was at school one day.

If you've a wiring diagram I could look at that would really help. I've got no idea where to look for wiring diagrams outside of the owner's manual (coincidentally the car didnt come with that either so I had to find one online)

I can work on the car and get some more later when it dries up a little outside (maybe an hour or two, it just rained where I am) but I've got this picture right now
20200322_174640.jpg

If you can see these wires are coming off the condenser itself. There's two red wires and a green ground wire. The red wire on the top is the wire you have tap the switch into to ground it out.

If there's any way you could either give me or point me in the right direction to get a wiring diagram that would be greatly appreciated.
 

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Can't scan, but can take a picture and attach.

The green wire should be grounded on the compressor side of the connector, so the connector should have 3 pins. Oddly enough, they are all red on the compressor side (the male side). On the car side, they are Green w/Red, Red w/White, and Red w/Black.

Maybe when it is dry you can see which side of the connector is modified and which wire is the one that was modified. I don't understand what they were trying to do, but I would bet that they were trying to bypass the thermal protector OR, there was a break in the wire somewhere between the thermal protector and the MICU, and this was their shadetree way of fixing the wire harness.

Then again, if the clutch will only work with that wire grounded out and the system works fine, then maybe just leave it. Might want to re-wire it to make it more robust and more professional (and get rid of the switch) instead of spending hours trying to find the break in the wire.

To diagnose it properly, you would make continuity checks between that connector and the connecter at the heater control panel. I'm pretty sure that the MICU provides a signal, and the circuit grounds through the heater control panel. If the thermal protector blows, it breaks the circuit and the clutch won't engage. In your case, it may be there is a break in the wire from the connector to the control panel, or perhaps the control panel is damaged. So, they grounded it out so the thermal protector was no longer in the circuit.

Did you know you can run a diagnostic on the A/C control panel? I have it listed out search "Hot air not blowing when set to max heat. Back flush heater core?"
 

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Discussion Starter #14
So I looked at the wiring diagram you sent. If I'm seeing it right the red/green is the wire connected to the tapped wire and on the compressor and that's for the thermal protection.
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Also after driving the car some today, the fuse blew out again and it's at the point where the fuse blows whenever you crank the car up and the compressor tries to run.

I'm not sure what to do from here because I'm not getting readings from my multimeter from any of the wires no matter what I do (I may be doing it wrong). Should I try following the cables from the compressor to the fuse box/battery?
 

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something I've heard lately is to be sure of your refrigerant type, that there is adulterated & mixed stuff in the can. Don't know if necessary to get AC shop to check & charge system (you might be able to get them to inspect it too) its a shame its come to that where a guy can't work on his own car w/o worrying about fraud freon.
 

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Logan,

I'm a little confused. In the second photo, you seem to be holding the harness on the car side because it has Red/Blk, Red/Wht and Green/Red wires. It does not appear to have been modified. But the other photo shows the compressor side wire that has been hacked on, and I thought you replaced the compressor. So you shouldn't have the modified since you installed a different compressor. The new compressor should have come with the correct (non modified) wiring. Before I can help you diagnose, I need to understand what you actually have now.

Since the previous owner grounded out the Green/red wire, he/she was clearly trying to bypass the thermal protection.

With the correct wires installed on the compressor and a good thermal protector, the compressor side of the harness should measure as (this is with it disconnected from the car harness):
-Terminals 1 to 3: Zero resistance
-Terminal 1 to compressor case: Infinite resistance
-Terminal 3 to compressor case: Infinite resistance
-Terminal 2 to compressor case: 3 to 3.5 ohms (this is the clutch coil)

Once you can verify that the compressor side of the wiring is correct, you can then look at the car side of the harness.

More info please....
 

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Discussion Starter #17 (Edited)
I'm so sorry, I didn't mean to cause confusion. The wire that's being tapped into is one of the plain red wires on the compressor side. We did replace the compressor but the compressor would not work without the switch wired to it. I didnt want to, but we tapped into it until we could figure out what's causing all this.

After getting a new multimeter (mine just so happened to kick the bucket while doing this) and testing the compressor side connector, I can tell you this:
Terminal 1 to 3: unlimited (this could be I just wasnt able to get a good connection)
Terminal 1 to case: 0 ohms
Terminal 2 to case: around 3-3.5 ohms (I've got an analog multimeter so I cant be exact)
Terminal 3 to case: 0 ohms

Edit: put the wrong readings
 

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And this is with the connector not connected to the car-side wiring harness? And is this with the cheater wire still attached?

  • 1 to 3 should be zero ohms of the thermal protection is good. By saying unlimited, do you mean infinite resistance? If it is infinite, then the thermal protection is bad
  • 1 to compressor case should be infinite (assuming the cheater wire is not attached)
  • 3 to compressor case should be infinite (assuming the cheater wire is not attached)
Can you confirm?

At this point, I would say you have a break in the Red/Black wire that goes from the compressor to the heater control panel (or something wrong with the heater control panel). Or, you have a short to ground in the Green/red wire that runs from the compressor to the underdash fuse box.

Both of those wires go though a big 23 pin connector to the right of the brake fluid reservoir (marked C101 on the diagram). You could open that connector and check for continuity for each of the two wires (separately), and no continuity from the wire to ground. If that is not correct, you might be able to just get that harness at a salvage yard, or you will need to trace along the harness and find out where it is bad.

If I understand how the circuit works, the control panel grounds out one side of the thermal protector when you turn on the air, and the MICU (part of the underdash fuse box) looks at the other wire to detemine if it can see it is grounded. If it is not (i.e. thermal protector has tripped), then it will not turn the compressor on. Since you could get it to work by bypassing the thermal protector to ground directly, I would be the problem is in the wire from the compressor to the control panel. But that doesn't explain the fuse tripping.

Not sure I can help much more. These sorts of things can be aggravating. Good luck.
 

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Discussion Starter #19 (Edited)
I tested the connector again with the switch off:
  • Terminal 1 to 3: 0
  • Terminal 1 to case: Infinite
  • Terminal 2 to case: 0
  • Terminal 3 to case: infinite
I'm going to look at the connector by the brake reservoir and the underdash fuse box.

It is very frustrating, but thank you for all the help
 
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