A/C Issue! Please Help!

[kslust]

Alright, recently I have been having problems with the A/C in my 2007 Lincoln Town Car Executive L. The A/C will work great and all of the sudden it will stop coming out of the vents, although the fan is still blowing (can hear it in the dash) but it barely trickles out the vents. I replaced all of the blend door motors yesterday, with the exception of the defrost one and still does it. What could it be, I was thinking maybe it was the head unit, but I don't want to switch it out and still be stuck and out of pocket for a new unit. Any help would be great thanks!

[First Class Limos]

Well whoever told you to replace the blend doors just cost you alot of money for nothing.

[RoyalFleet]

I am not sharp on 03 or newer TC, but if it was an 02 most likely would be a vacuum problem. If it stops blowing out when you accelerate the vehicle chances are this is what is.

[kslust]

Swapped the EATC...... Crossing my fingers hoping it works, we'll see. So far so good.

As for the Vacuum issue, we checked (no apparent leaks). It doesn't just happen with acceleration, it just happens....

P.S. Thanks captain obvious about the blend doors! P.S. I replaced them because the EATC codes coming back said to, and it only took an hour and no cost as I had some already..... so yeah....

[Los Olivos Limo]

Make sure the 'Auto' button on the dash is on and if the outside temp is lower than the dash temp setting you might not get air through the vents.

[kslust]

Tried the "Auto" bit, but it doesn't make a difference. Thanks!

[Fairfax Limo]

I have this same exact problem on a 2007 also. Its a vacuum problem. The system is set to default to defroster, because of safety. So if you lose vacuum control for the vents/floor it will blow out of the defroster by default. I think when you hear it blowing, but its only trickling out of the vent that its actually blowing out of the defroster. I've had it fixed under warranty. I'll look up the records tomorrow and see what they replaced. The bad news is, it has started to do it to me recently intermittently and now out of warranty.

[kslust]

Im trying to find this vacuum line, as per Tim @ BLVD. No luck yet.... It's driving me crazy, my mech. says he doesn't want to try and diagnose it unless it's happening. Yet it only happens intermittently!! It's driving me crazy!!

[steve_b]

I have this same exact problem on a 2007 also. Its a vacuum problem. The system is set to default to defroster, because of safety. So if you lose vacuum control for the vents/floor it will blow out of the defroster by default. I think when you hear it blowing, but its only trickling out of the vent that its actually blowing out of the defroster. I've had it fixed under warranty. I'll look up the records tomorrow and see what they replaced. The bad news is, it has started to do it to me recently intermittently and now out of warranty.

Engine vacuum is *NOT* used for the hvac controls on these cars. Steve

[steve_b]

Alright, recently I have been having problems with the A/C in my 2007 Lincoln Town Car Executive L. The A/C will work great and all of the sudden it will stop coming out of the vents, although the fan is still blowing (can hear it in the dash) but it barely trickles out the vents. I replaced all of the blend door motors yesterday, with the exception of the defrost one and still does it. What could it be, I was thinking maybe it was the head unit, but I don't want to switch it out and still be stuck and out of pocket for a new unit. Any help would be great thanks!

Karl,

You most likely have an evaporator that's freezing up, usually occurs after several hours of continuous use. Two possible causes are the a/c clutch relay contacts are welded together preventing the compressor clutch from cycling or the orifice tube is leaking and flooding the evaporator with refrigerant.

Steve

[kslust]

Karl,

You most likely have an evaporator that's freezing up, usually occurs after several hours of continuous use. Two possible causes are the a/c clutch relay contacts are welded together preventing the compressor clutch from cycling or the orifice tube is leaking and flooding the evaporator with refrigerant.

Steve

Thank you all! Especially you Steve! The problem was that in fact;

Diagnosis for future:

A/C Clutch Switch problem. The A/C clutch Switch (Low Side Pressure Sensor) located on top of the A/C Drier/Accumulator (sensor with an electrical connection) was bad, the original reason for mis-diagnosis of this is because, where normally when this goes bad the A/C compressor does not come on, but in this instance it would not tell the compressor to turn off (very rare apparently). This in turn keeps the compressor running constantly making the evaporator freeze up in a block of ice, and seeing that ALL air that goes into car must go through the evaporator, but couldn't because it was a block of ice. Then yeah, no air flow, but you can hear the fan kicking away.

To confirm freezing up, the A/C Lines will be caked in frost indicating an evaporator freezing up.

Replaced switch from auto parts store $12 dollars screw off, put new one on! All is good air flow is wonderful!

Thanks All! and I hope this helps someone in the future!

P.s. there is no vacuum lines that have any bearing on the function of the A/C units, all doors are controlled electronically and no longer controlled via vacuum.

[nvthslex]

Its the small things that cause problems, but rather the small things before shelling out the big bucks.

Another local limo company has an a/c problem that the front is working cold, but the rear is hot air. The front blows 45 degrees while the rear is 97. The a/c was fully charged.

In the rear if you switch from a/c to heat it makes no difference its always blowing at 97 degrees.

Its built by AHA, and is year 2000.

Any clues of where to start ?
Would like to help him out, thank you.

[Fairfax Limo]

Its the small things that cause problems, but rather the small things before shelling out the big bucks.

Another local limo company has an a/c problem that the front is working cold, but the rear is hot air. The front blows 45 degrees while the rear is 97. The a/c was fully charged.

In the rear if you switch from a/c to heat it makes no difference its always blowing at 97 degrees.

Its built by AHA, and is year 2000.

Any clues of where to start ?
Would like to help him out, thank you.

check the heater hose that goes back to the heat/ac unit in the back. if its hot or warm, I'd put a manual cutoff valve on it inside the engine compartment.

[Bigdan]

See if you can touch the piping to or the evaporator itself, if it isnt cold replace the expansion valve.

[nvthslex]

thanks guys, I will pass the info along.

His a/c dash lights also went out on him today, I am assuming it would be a fuse.
Like nothing works in the front, and he spent $200 getting a full a/c charge the day before.