Only 2 things will take out the clutch on a comp, low voltage and high pressures. Voltage at comp should be with in .5 volt of battery voltage, what do you have ?

 

I'll check voltage tonight but last time I checked I think it was around 13.0V with truck running. The damaged compressor worked off and on today. Seemed like I would work for awhile, quit and I'd turn off, and 30 minutes later would work for awhile. Don't know if that's typical for dying compressor or maybe a clue that high pressure is to blame?

 

Lost my AC compressor last year and in process found that TIPM AC control was bad. By-passed TIPM with relay, 15 amp fuse, etc. and also replaced engine fan clutch for good measure. My problem now is that I keep burning up AC compressors. Like 6 in a year. I get a month or two out of them and them they fail. Repair shop keeps saying the clutches are going out. These are rebuilt units and we investigated new options but say does not make sense to by new. Better warranty on rebuilt and they say new and rebuilt are likely coming from same place. Also, I'm already committed to rebuilt now for warranty purposes. Simple things like clean lines, high pressure sensor, compressor oil, voltage at compressor have been checked and seem OK. Today, however, when my compressor was in death throws smelled it burning up and think I saw sparks at compressor. Could it not be grounded well? Really getting frustrated with this POS AC system and would appreciate any help

did you replace the orifice tube-filter and receiver/dryer when any of these comp. were installed?
If not flushing the lines will NOT get all the junk out. If nothing else the orifice tube/filter will catch the junk, cause a restriction, raise the pressure then poof.

 

Is the compressor gernading or the clutch just takes a crap

 

You can't check the voltage at the compressor without the compressor coil being in the circuit... there is the chance that the system can't supply the current required to keep the coil engaged.... in that case, testing with the coil connected would show low voltage like mentioned above...

I also agree about the changing of the orifice tube-filter.... if this is plugged or restricted it would easily contribute to very high pressures.. and damage to the compressor...

 

So after AC clutch finally took a dump I took back to the shop today. Just called me back and said they are stumped, totally. Now, Napa won't warranty since I've gone through so many compressors and I'm back to square one. Hopefully folks here can help since I'm largely going on my own on this one. Too expensive otherwise, especially when shop does not have confidence in their solution.

So shop says the system is building high pressure (enough that the compressor is coming apart). Like 400PSI when sitting still. Bear in mind I have already changed fan clutch and high pressure sensor in past few months so don't think these are problem. They say the condenser is clogged and causing problems and needs to be replaced. On top of that, they say that the compressor is still receiving power when switch is off, but only for 5-10 minutes after switch is off??? That does not make sense and I really don't see how that is the problem when I by passed TIPM with relay and 15 amp fuse as described on this forum. Also, system burnt up clutch before bypassing TIPM...

SO here are my questions: 1) could my bypass job of TIPM possibly have created electrical problems and should I bite bullet and get new TIPM before going further?

2) How would you guys proceed? Replace all AC components including condenser?

I'm really at a loss and frustrated enough to get rid of this truck. If it did not run so good with 230K she would have been gone long ago in this south AL heat!

 

you could always co the larry the cable guy route and put a house window unit in your back window with an inverter lol
id defanatly change the orifice tube and dryer havent ever herd of a condencer stoping up to where it would cause that kind of high preasure situation id also check your tensioner pully if it is going bad it might be causing your belt to slip on the compressor making extra heat

 

Orifice tube and dryer were changed with most compressor swaps (I think 4 of the 6 compressors). I know I will need to change now but don't think issues with those were the problem as burnt up even after changing these. I don't think tensioner pully is going bad as that SOB was hard as heck to move when I changed fan clutch recently. Would I just feel slop in the belt if going bad?

 

This is stupid question but want to make sure I'm doing correctly to eliminate electrical issues from TIPM bypass first. To check voltage at compressor, I unplug from compressor and set volt meter to DC. One line to plug, one to ground and should read around 13-14 with AC button in on position, correct? The post above about being unable to test without compressor in circuit has me scratching my head a little. How would I go about differently?

 

by passed TIPM with relay and 15 amp fuse
So how is the AC system being monitored and controlled by the ECM???
Who is looking at the low pressure and high pressure sensors to make sure the system is running properly and safely???
shop says the system is building high pressure (enough that the compressor is coming apart). Like 400PSI when sitting still.
Will the system shutdown when the low pressure is too low and when the high pressure too high???
Looks like the answer is NO.
system burnt up clutch before bypassing TIPM...
How many times before bypassing??? One
How many times after bypassing??? Six

get new TIPM before going further

I would do that.

 

The only part of the system that was bypassed was the compressor. Basically, I inserted a relay and fuse between the compressor and switch in the cab. The engine fan still kicks on when the ac switch is turned on and the pressure switches are still in the TIPM loop so my thought is that the ac system is still largely being controlled by the TIPM and ECM, with simple bypass of power supply to compressor. Does that make sense or am I missing something here?

 

In the TIPM there is a Relay-Clutch-A/C Compressor. There are two circuits on this relay, one control circuit and one power circuit.
The control circuit consists of the relay coil which will be controlled by the ECM.
The power circuit consists of the clutch which would be energized by the relay when ECM energizes the coil.
If you did the bypass correctly there would be no need to have a switch inside the cab to switch on the clutch. The power going to the clutch should be controlled by the ECM, NOT by a switch inside the cab.
I think you didn't bypass the control circuit.
You just bypassed the power circuit with a relay and a switch.
I think YOU are controlling the power to the clutch.

In another words the bypass relay coil should be controlled by the ECM.

 

At certain psi 's the compressor needs to cycle. If it runs continuous you'll continue to go through clutches. Also a clogged up condensor is quite possible. With a/c running see if the line going into the condensor gets extremely hot while the outlet stays room temp. If so I'd say the condensor is stopped up. Before throwing a new one at it a good start is to blow it and the other lines out with NITROGEN only.

 

So we are all on same page...below is link to post describing what I did to bypass TIPM. I assume this is correct. ECM is still sending power, but to relay instead of TIPM, and relay sends power to compressor. I believe all other AC components will worked as wired since ECM is still in control. And in reference to the above post the switch I'm refereeing to is the AC on/off switch on the dash controls, not an extra switch I added.

http://www.cumminsforum.com/forum/3...in/306332-possible-diy-fix-ac-compressor-clutches-going-bad-16.html#post6383909

 

Where did the replacement fan clutch come from? I have a buddy that does a/c work, that will not use a aftermarket clutch on a Dodge cummins engine.

 

Was not aftermarket and seems to cycle on and off as designed.

 

1) could my bypass job of TIPM possibly have created electrical problems and should I bite bullet and get new TIPM before going further?
NO if you did it correctly.
Cut LB/OR wire at TIPM, B+ to relay pin 85, relay pin 86 to LB/OR wire.
Cut DB/YL wire at TIPM, B+ to relay pin 87, relay pin 30 to DB/YL wire.
2) How would you guys proceed? Replace all AC components including condenser?
I would just replace all AC components including condenser,evaporator, compressor, drier and orifice tube assembly and blow out the prssure line.

 

I had the same problem it the feed line that has the orfice tube in it none change able. I had to get mine from the dealer. what happens is when the compressor gives it sends metal into that line and clogs up the orfice tube. Either that is your problem or you may have to much oil in the system. Good luck man hope you fix it

 

Here's a follow-up on my AC system. After breaking serpentine belt at the gas station due to totally broke AC compressor pully, had no choice but to fix system. Put new 4 seasons compressor, new condenser, accumulator, and line with orfice tube. Vaccumed and recharged system and high pressure was still getting to 400psi. Fan was roaring so was not fan clutch. However, even with engine fan going a piece of paper would not stick to condenser. After scratching head for awhile put big fan in front of condensor and pressure dropped to around 300 psi. Thought maybe had air restriction and had idea to rinse and clean radiator, air cooler and tranny cooler. Hooked up gauges after cleaning and everything worked perfect! Pressure would run up to around 250, engine fan would kick on and drop just below 200. AC is way colder than I can ever remember to. Engine running slightly cooler as well (Duh). I guess on these trucks with so many parts between engine fan and condenser things have to be real clean to work as designed. Learn from my $1300.00 lesson and keep that stuff clean..even if they don't appear to be clogged with crap. Mine visually looked OK but bunch came out when rinsed.

 

OK we all missed it. It's the air flow problem!!!

 

The guy you quoted hasn't posted in over 4 years, probably won't answer.
rockauto.com will have what you need.
If the belt is squealing when compressor is engaged, you more likely need a new tensioner and belt.

 

Thanks for the reply.