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Quick question, 2003 AC compressor not coming on, AC RELAY is energized

dano

Full Member
Joined
Dec 3, 2004
Messages
48
Location
Central Ohio
Ambient temp outside is 82 degrees, low and high side pressures are equalized at 125 psi due to not cycling.  yFound a clutch control diagram for an 02, think mine is similar or same, AC relay is on, I'm guessing low pressure switch is the issue, but I wouldn't think 125 psi would be an issue.  Looks like compressor gets it's ground from low psi switch?  Have had intermittent issues recently but today compressor will not cycle.  Compressor is not locked up, turns freely.  Thanks for the help. 
 
Locate the low pressure switch at the accumulator and unplug it and plug back in to see if the system works. If does then could be a bad connection or switch problem. Use a paper clip and jump across the 2 pin holes at the wiring connector and the compressor should come on. It will not cycle but will likely start blowing cold. If it does then replace the low pressure switch and make sure when you plug back in that it has a good connection. I have seen older plugs wallow out at the female hole and need to be pinched to help tighten or just replace the pigtail. Also, make sure the pin holes in the connector do not push out backwards as you plug back in.
 
Checked connector at compressor, have 14vdc across the two wires. Compressor coil measures 4.1 ohms. Compressor is free but clutch does not engage. I'm thinking clutch coil is toast. Anyone know a good value for AC compressor coil?  Thanks. Doesn't even appear to be trying to engage, no sign of metal or clutch material or physical damage around clutch.
 
That is not the correct switch to check with my instructions. I am talking about the low pressure switch at the accumulator at the passenger side firewall. This switch has to make a connection internally when pressure is high enough, to work the system. The low pressure switch is designed to protect the compressor when pressure gets too low and then does not move the internal a/c oil inside the system that protects moving parts.
 
I have 14 VDC at the compressor, and low psi switch would prevent that if it was an issue. Relay, fuses, controller, hi and low pressure switches are all in control side.  system is commanding compressor to kick on ( voltage present between the 2 wires that plug into the ac clutch) but it is not. AC clutch coil reads 4.1 ohms, I'm thinking that sounds reasonable. Anyone ?  Thanks.
 
Do you have the auto or manual HVAC
 
Sorry, I have auto AC.  I went out later to pack up and as I suspected, the AC clutch kicked right in.  I read schematics at work every day, if my schematic is correct I either had an intermittent clutch failure or possibly bad connection at the clutch coil connector.  I removed connector at AC clutch earlier today and verified 14 VDC between the two wires on harness side.  Checked resistance on clutch coil and it climbed steadily over a 5 second period maybe (typical on most coils I think) and stopped at 4.1 ohms.  All of that seems normal to me, clutch should have engaged with 14 volts on it, yes?  Next time it happens I will jumper sytem voltage directly to clutch, but from what I'm seeing and thinking, control side looks ok- assuming the connection from harness to clutch is ok.
 
Any luck on this?  I'm having the same problem with my '02 with manual controls.  I'm getting 13.5volts at the harness for the clutch and had already tried jumping both the low and high switches in the hopes that one of them was the problem.  My wife is ready to divorce me over the lack of AC in this Florida heat.  That may be cheaper than taking it in to the shop so...

My air would intermittently quit blowing cold (compressor disengaging, but not quickly, it would work for weeks and then just decide one day in the middle of a drive to disengage)  Then it would come back on if we shut the truck down for a few hours and work fine or not.  No rhyme or reason to it.  We dealt with this for a year, but now it's just not engaging at all and I have to get it fixed. 
 
Sorry I didn't update this sooner.  I see it all the time where users post on here then the thread dies....and they don't post a resolution.  So....better late than never.  My AC clutch material was non existent.  It was metal to metal.  I replaced the AC clutch and I've been good since, probably been a couple of months now.  Original clutch coil was still good, but there wasn't enough material on the clutch to grab.  Bought it on amazon or ebay, I can't remember, but it was just over $100.  I am a former ASE certified master tech so this was not difficult, but I will say getting access to the snap rings required fan and fan shroud removal.  I was able to complete the repair from above.  You mill most certainly need a mirror to verify snap rings are set correctly.  The old clutch came off fairly easily which is surprising since my truck has never been garaged, it has 180K on it and I have never washed the engine bay. 
 
Was driving and noticed all guages on instrument panel went to zero.  Now the air conditioning, dome light, electric locks and windows don't work.
I checked all fuses and they are good.  Has anyone else had this problem?????????? Is there one relay that handles this???
 
Ok, so as I know people aren't ignoring you, but I believe I seen this somewhere. Make sure that your battery is good. Failing batteries do weird stuff to vehicles. And make sure that your posts are clean and well connected. As far as the ac, check the low pressure switch has voltage, first. I know that someone will get to this thread that knows what's happening and gives you a more intelligent answer than I am giving you.
 
No we are not ignoring them but we have a life away from the site. 2,000 miles road trip in one week.

Only if I see a my AV does not start and I'm stuck on the road I will post from my smart phone.

This old guy is beat and tired.
 
Search Ignition Switch...
 
Not sure how the thread turned to this.....but when it happens again, carefully and lightly turn the ignition key one direction then the other to see if your listed items power up.  Sounds like classic ignition switch failure.  All manufacturers are guilty......
 
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