Yet another A/C thread

DFW_Motorrad

New member
Hey everyone. I have a 2004 Freightliner (says Dodge on title but okay) 140" high top cargo.
I just bought it and got it running. But now I'm moving up to NY from TX at the end of July. And my A/C is insufficient. When I say insufficient, I mean non-existent.

Here's what I know:
Compressor works. Clutch engages/disengages with the A/C button.
Condenser fan works, and spins the right direction.
Pressures are good. 40 low side, 200-300 high side depending on the condenser fan.
The recirculate flap is broken. I'd have to remove the whole box to fix it, but I'd be willing to if I have to.
Fan speed only works on 1, 3, and 4. Speed 2 just gives me the same as speed 1.
Temperatures are around ambient across all vents.
Cabin air filter is new and installed properly.

Here's what I'm not sure of:
Interior temp sensor might work? Fan spins.
Temp control knob might work? I get heat when I turn it to full hot, but nothing cold when at full cold. I may take it apart again and spray electrical contact cleaner in the potentiometer.

And that's about all I can come up with.
Please help, I don't want to drive in 100+F temperatures with no A/C.

-Ryan
 
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Midwestdrifter

Engineer In Residence
So, the top center 2 vents are not cold?

What is the temp of the low side line coming from the txv? Cold enough to form condensate?

The first step is a full evac and measured recharge, as improper charge is very hard to diagnose on txv systems with variable compressors.
 
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DFW_Motorrad

New member
Top 2 vents are ambient. Passenger one might be slightly cooler, but still around 90F air.

The only line that got moderately cold was the bottom line on the passenger side of the txv. I assume this is the one you're referring to. Not cold enough to create condensation on a hot and humid day, but relatively cold to the touch in a hot engine bay. My IR thermometer is at work, so if you need concrete numbers I can do that.

I'll take it to a local A/C shop this week and have them evacuate completely and refill with exactly 1.9 lbs. I only have manifold gauges.
 

DFW_Motorrad

New member
Fixed.

50-60F air outlet temp read from an MBII. When ambient temp is 107 today and my recirculate flap is broken.

I replaced the txv because $13 and 4 o-rings so why not (took maybe 10 minutes), vacuumed for 30 minutes, and filled with cans. They are 12oz cans so I used 2 full cans and approximately half of another one. It filled VERY slowly compared to what I am used to. I'm used to being able to throw in 2 cans in 15 minutes. This took about an hour and a half to take 2 cans. Might have been the connections between the gauges and the lines, or these might just fill slowly.

I think the txv might have been fine and I just wasn't used to it taking that long so I thought it was done after 1.5 cans. But oh well, it's working great now. Thank you Midwestdrifter.

Anyway, I got the hitch wiring done, CEL fixed (boost pressure sensor was an intake pressure sensor), head unit replaced with a bluetooth unit, blown speakers replaced, and now A/C fixed. Now I'm going to change oil/filter again before I leave and that should be it. Hauling my race bike and MR2 up to NY. :D:
 

pfflyer

Well-known member
Fixed.

50-60F air outlet temp read from an MBII. When ambient temp is 107 today and my recirculate flap is broken.

I replaced the txv because $13 and 4 o-rings so why not (took maybe 10 minutes), vacuumed for 30 minutes, and filled with cans. They are 12oz cans so I used 2 full cans and approximately half of another one. It filled VERY slowly compared to what I am used to. I'm used to being able to throw in 2 cans in 15 minutes. This took about an hour and a half to take 2 cans. Might have been the connections between the gauges and the lines, or these might just fill slowly.

I think the txv might have been fine and I just wasn't used to it taking that long so I thought it was done after 1.5 cans. But oh well, it's working great now. Thank you Midwestdrifter.

Anyway, I got the hitch wiring done, CEL fixed (boost pressure sensor was an intake pressure sensor), head unit replaced with a bluetooth unit, blown speakers replaced, and now A/C fixed. Now I'm going to change oil/filter again before I leave and that should be it. Hauling my race bike and MR2 up to NY. :D:
Congratulations. Toyota MR2? What year?
 

O6sprinter

New member
Hay guys, I don't mean to hijack this thread but I don't wanna start another a\c thread.

My 06 140" high top 141k cargo van with bulkhead between cab and cargo.

I replaced the compressor, dryer, expansion valve & a\c pressure switch.
I purchased the parts from europarts SD. The chance out wasn't that bad.

I evacuated the system, it held the vacuum.

I recharged the system with 12oz can from Walmart, from my research on other forums as well as hear. the Walmart $5 can is all 134, no oil. ( It's my understanding not all parts stores cans are) 2 & 1\2 + cans .All went well, low/liquid side 40-50 high side 300 to 375 the condenser fan seams to cycle as it should.

My problem, it's stupid cold!!!! The a/c clutch won't disengage\ cycle. I have to push the button to disengage the clutch. I know there a sensor in the ductwork, does it control the clutch????

The temperature control knob ( I'm sure it has a technical name) works, controls the heat.

How is clutch controlled?? It's full time engaged, won't cycle!!!!
The only way to disengage the clutch is to push the button..

Thanks, Lee
 

Midwestdrifter

Engineer In Residence
B1009 005 9009 05 Coolant circulation pump (M51)

Short circuit to ground(-).
a. Cable A81.1/2 to X82/5 has a short circuit to
ground(-).
b. Cable X82/5 to M51/2 has a short circuit to
ground(-).
c. Coolant circulation pump (M51) is faulty.


Most vehicles made since about 1999 use a variable displacement compressor. This includes the T1N. The compressor clutch is controlled by the ATC unit. It will only cut out the ccompressor when the following occur.

High side pressure too high.
High side pressure too low.
Evap under temperature (freeze up risk)
Engine over temperature

The temperature of the evap is controlled by the expansion valve and the compressors control valve. This sets the evap temperature at around 35-45F. If it drops too low the compressor will be cut out by the ATC. This should not happen during normal operation. If your evap temp (you can read via scanner, or from the ducts) is above 34F, there is no problem.

The compressor control valve senses low side pressure. If it rises above the setpoint, the compressors displacement increases. If it drops below the setpoint, the displacement is decreased. The variation in displacement is dynamic, and calibrated with the TXV. This is why the TXV and compressor control valve are matched, and should only be replaced with units of the same brand when possible. The variation in compressor displacement varies from 10-100% as needed.


In order to control cabin temperature when using the AC, adjust the temp knob as needed, and the ATC will partially reheat the air to provide a stable temp. This does not increase the AC load appreciably. You can also adjust the air flow via the vent dampers.
 

O6sprinter

New member
Thanks Midwest,

I'm going to call that good news!!

With a digital thermometer idling in the driveway, I'm getting 45° f and less
. I'm in South FL the ambient temperature sensor reading 90° not sure what the humidity was. FL this time of the year I'm sure it was high!!!!
City driving, it's comfortable with the temperature control adjusted up a little. That's until the sun hits the windshield, that warms it up fast. I talked to window tint guy $275 for the UV windshield and both sides.

I was on the highway 50-60 mph, in a Dow pour. I didn't have the thermometer with me but it was a lot cooler. Uncomfortable cold with the temperature control on Hi.

The temperature control does put heat in the cabin, maybe not enough? My first guess about the B1009 ( coolant circulation pump ) is it's shorted out. From my understanding, it's only for heating the cabin not engine temperature. PLEASE correct me if I wrong!!!!!

Looks like the pump is $140, proudly a good idea to replace the hoses at the same time.

I also added die just in case of a leak. I'll give it a week or so check for Leak's and through the gauges on. If it's not leaking and the Hi & low pressures stay good. I'll call it a win! If I see something out of line it's going to a pro. Ask them to suck all the freon & oil out start over.


Thanks again Lee
 

Midwestdrifter

Engineer In Residence
I am assuming your engine gets up to temp (180F or so).

With the control on high temp setting, you should easily overpower the AC. Note that the top center two vents bypass the heater core, so they AC only.


With the AC off you should be able to get 120F air out of the vents with the heat on high temp. If not, you have one of the following issues.


1 malfunctioning ATC. Could be the knobs potentiometer, etc. There are services which will rebuild for around 100-150$ Unplug the heater control valve to test. With a scanner you can read the cabin temperature from the ATC, just to confirm it is seeing the right temp. THe ATC reads the cabin temp through the small vent on its front. From there it determines how much coolant is needed based on the dial setting.

2 Your heater control valve is sticking closed. Its default position is full open, so unplugging it should yield full heat. The valve is located above the engine near the black HVAC duct.

3 You are low on coolant, and the heater core is not getting fully filled. Check your coolant level. If you are constantly getting low coolant with no signs of leakage, you may have a head gasket leak putting gas into the coolant system.
 

O6sprinter

New member
Yes the engine temperature gets up to 180 -190F. I'll try with the top center vents close.

I wouldn't be surprised if the if the ATC has issues, I've read they are known to have problems. To start with how can read the ATC With a scanner? ( MD 802 ) I tried, couldn't find the setting. If anyone can help it would be greatly appreciated!!!!

I'm not having any coolant problems. Hope it stays that way!!!!!!
 

DFW_Motorrad

New member
Congratulations. Toyota MR2? What year?
Thank you. 1989 with a Gen 2 3S-GTE from ATS Racing.

Yes the engine temperature gets up to 180 -190F. I'll try with the top center vents close.

I wouldn't be surprised if the if the ATC has issues, I've read they are known to have problems. To start with how can read the ATC With a scanner? ( MD 802 ) I tried, couldn't find the setting. If anyone can help it would be greatly appreciated!!!!

I'm not having any coolant problems. Hope it stays that way!!!!!!
Try flicking the temperature knob around to clean up the potentiometer. My MBII scanner will tell me the requested temperature, evaporator temperature, interior temperature, exterior temperature, and air outlet temperature. I'm not familiar with your scanner but I found this video:
https://www.youtube.com/watch?v=ifqQnn0X6SM
Right around the 4:00 mark is where I would assume you would find that. It's super low quality so I can't read the screen but just poke around in there and see if it's in there. It would be under heater controls or heater control unit.
 
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Nautamaran

2004 140” HRC 2500 (Crewed)
FWIW I can’t connect to the ATC module with my MD-802... firmware is whatever it was loaded with when I bought it last spring. I’ve not spent any time figuring out if/how I should update it... there’s the risk that some coverage would fall out with an update.

-dave
 

Midwestdrifter

Engineer In Residence
The mD 802 will let you use as many versions of the various software as you need. You can keep them in a folder on your computer and swap them out at will.
 

O6sprinter

New member
I tried every possible combination, I'm going to look into updating my 802. I just stumbled upon a more pressing problem.

Oil in my radiator, hopping it just the oil heat exchanger.

Thanks for your help Lee
 

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