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ClassicFleet
09-16-2013, 06:08 PM
Need some help on a 2005 model A/C system. Condensor fan will not come on. When A/C switch is turned on, compressor will not go off. Will run the high side to 400+ pressure if not switched off. Has tripped relief valve and spewed freon only once. Have replaced the pressure transducer on drier. Have flushed evaporator, lines and condenser. Unplugging Water Temp Sender will default the condenser fan on and it will operate wonderfully. We have used our Power Probe to apply power to Red/Black wire at the back of ATC and can kick the condenser fan on. We have gone so far as to recover all Freon and only put 1lb back in. Will still build over 400 pounds of pressure. This silly thing will cool until pressures build and then starts putting out warm air until we have to switch it off to prevent Freon loss. Last ditched effort -- we borrowed an ATC from another unit this client has. This produce no change in our vehicle. Reinstalled in original unit and all works well in it. We do not believe it to be the ATC.

We do not have a DRBIII scanner. We have hooked the Genesis and the Snap-On Solis Ultra but cannot get system to run a self test. We are down to putting it back together and taking it to Freightliner or Dodge.

Anyone have any information that might be helpful? We have utilized many helpful suggestions on this forum, but no results this go-around. Open to all suggestions.

Aqua Puttana
09-17-2013, 04:38 AM
...Will run the high side to 400+ pressure if not switched off. ...
They mention excessive high side pressure in the VA Service Manual. Section 24

From the chart.


The low side pressure is
normal or slightly high, and
the high side pressure is too
high.

1. A/C condenser air flow restricted.
1. Check the A/C condenser for damaged
fins, foreign objects obstructing air flow
through the condenser fins, and missing or
improperly installed air seals. Clean, repair, or
replace components as required.
2. Refrigerant flow through the
receiver/drier is restricted.
2. See Receiver/Drier in this group. Replace
the restricted receiver/drier, if required.
3. Inoperative radiator cooling
fan.
3. Test the radiator cooling fan and replace, if
required. Refer to Group 7 - Cooling.
4. Refrigerant system overcharged.
4. See Refrigerant System Charge in this
group. Recover the refrigerant from the refrigerant
system. Charge the refrigerant system
to the proper level, if required.
5. Air in the refrigerant system. 5. See Refrigerant System Leaks in this
group. Test the refrigerant system for leaks.
Repair, evacuate and charge the refrigerant
system, if required.
6. Engine overheating. 6. Test the engine cooling system and repair,
if required. Refer to Group 7 - Cooling.
****
The low side pressure is too
high, and the high side pressure
is too low.

1. Accessory drive belt slipping.
1. Inspect the accessory drive belt condition
and tension. Repair as required. Refer to
Group 7 - Cooling.
2. Faulty A/C expansion valve. 2. See A/C Expansion Valve in this group.
Replace the valve, if required.
3. Faulty A/C compressor. 3. See A/C Compressor in this group. Replace
the A/C compressor, if required.
****
The low side pressure is too
low, and the high side pressure
is too high.

1. Restricted refrigerant flow
through the refrigerant lines.
1. See Liquid Line, Suction Line and Discharge
Line in this group. Inspect the refrigerant
lines for kinks, tight bends or improper
routing. Correct the routing or replace the refrigerant
line, if required.
2. Restricted refrigerant flow
through the A/C expansion
valve.
2. See A/C Expansion Valve in this group.
Replace the valve, if required.
3. Restricted refrigerant flow
through the A/C condenser.
3. See A/C Condenser in this group. Replace
the restricted A/C condenser, if required.

lindenengineering
09-18-2013, 11:56 AM
Need some help on a 2005 model A/C system. Condensor fan will not come on. When A/C switch is turned on, compressor will not go off. Will run the high side to 400+ pressure if not switched off. Has tripped relief valve and spewed freon only once. Have replaced the pressure transducer on drier. Have flushed evaporator, lines and condenser. Unplugging Water Temp Sender will default the condenser fan on and it will operate wonderfully. We have used our Power Probe to apply power to Red/Black wire at the back of ATC and can kick the condenser fan on. We have gone so far as to recover all Freon and only put 1lb back in. Will still build over 400 pounds of pressure. This silly thing will cool until pressures build and then starts putting out warm air until we have to switch it off to prevent Freon loss. Last ditched effort -- we borrowed an ATC from another unit this client has. This produce no change in our vehicle. Reinstalled in original unit and all works well in it. We do not believe it to be the ATC.

We do not have a DRBIII scanner. We have hooked the Genesis and the Snap-On Solis Ultra but cannot get system to run a self test. We are down to putting it back together and taking it to Freightliner or Dodge.

Anyone have any information that might be helpful? We have utilized many helpful suggestions on this forum, but no results this go-around. Open to all suggestions.

Obviously this is a customers vehicle and you have been asked to repair it! Si O No Senor?

What is its history, has someone been into it before trying to fix the issue or not? Or is this a sudden fault occurrence with no previous repair intervention.

It begs the question as to what is the state of the 40A maxi fuse and wiring under the drivers seat box and adjacent side fuse box, holder, pins,etc? Have rodents been busy under the seat? (Not so strange a possibility.)
For some reason these furry American creatures love Euro wiring for breakfast.

Do you have something like Mitchel on line to go through trace the wiring circuits?
Dennis

ClassicFleet
09-18-2013, 07:16 PM
Thank you for your suggestions. Yes, fleet vehicle. Four in this fleet. No damaged wiring. All fuses good. We have pulled more than 1/2 the dash apart verifying sensors and parts are acting as they should. If we crank it in the morning and drive, A/C works great. Stop and turn it off, pressures build on low side, and it will not work for another 3-4 hours until things cool down and pressure subsides. Pressure line gets so hot it will put a blister on your hand when you touch it. Proved that one by accident. As long as air is flowing across the condenser, A/C cools. Cannot get condenser fan to come on by itself in A/C mode. Can only get it to operate in default or sending power from relay or ATC head connector.

In answering last question, no, but we have found wiring diagrams plentiful on this site and on the web.

lindenengineering
09-19-2013, 01:24 PM
OK let's step back a bit.
In the morning upon start up does the system work as it should?
AND
Is the condenser fan operational after few minutes of usage?
Or more importantly does it work at all during this period of satisfactory operation?

What about the A/C compressor clutch?
Is this able to decouple either electrically and/or mechanically?

What charge is in the system?
It should be 1.9 lbs have you verified that?

Are you sure you have pure 134a refrigerant in the system and not some "cocktail" of different refrigerants?

I am working on a problem child TIN A/C at the moment.
Do you have access to any individual or shop that has a WIS info system or Mitchell?
Dennis

ClassicFleet
09-19-2013, 02:16 PM
Good morning Dennis,
The A/C clutch engages as it should. when the A/C button is pushed off, clutch disengages. pushed again, clutch reengages. Only clutch issue is that it is not being told to disengage when pressure builds. However, once pressure has built, and ignition turned off, clutch will not engage for the next 3-4 hours when temps and pressures subside.

condenser fan is never told to engage. ever.

We have recovered the system a couple of times. no contamination. We have charged to 1.9lbs. in an attempt to avoid high pressures, we experimented and only charged system 1lb, or 1/2 capacity. No change. still ran, never cut off and built pressures above 350lb.

I may have access to the Mitchell. We have Mitchells Medium / Heavy truck electronic on our laptop. This hasn't helped at all. I may have access to the Mitchell light version. I have found this forum to be much more helpful than all other resources on Sprinter related issues.

Dennis, thank you for your inputs.

lindenengineering
09-21-2013, 01:12 AM
I suspect you have a CONTROL problem.

I pulled the wiring schematics and took a quick look.

Without going into a confusing diatribe, why not send me an email link an I will shoot you a two page wiring schematic of the whole system. Frankly I cannot rule out the control module/wiring where many of the signals originate and require inputs to signal.
I might try to post them up on this forum any specific instructions?
Dennis

calbiker
09-21-2013, 02:18 AM
I just did some A/C troubleshooting. Does the electric radiator fan turn on when the A/C pressure sensor connector is disconnected? Have you measured pressure sensor voltage at the controller? I used a sharp probe to poke through the wire insulation in order to measure voltage.

Cal

lindenengineering
09-21-2013, 04:43 AM
I just did some A/C troubleshooting. Does the electric radiator fan turn on when the A/C pressure sensor connector is disconnected? Have you measured pressure sensor voltage at the controller? I used a sharp probe to poke through the wire insulation in order to measure voltage.

Cal

With the system running -in short yes!
Dennios

ClassicFleet
09-22-2013, 10:20 PM
If the water temp switch on the engine is unplugged while running, the Condesor fan runs. When the A/C pressure switch harness is unplugged while running, the fan will NOT turn on. This is the reason we replaced this pressure transducer. No change after replacing. We have ohmed each wire back to the ATC and all 3 wires good.

Keep coming with the ideas..........please.

ericw173@hotmail.com for the wiring schematic Dennis

lindenengineering
09-24-2013, 02:46 AM
Eric
A/C schematics sent.
Dennis