Hello,
I have read alot on this forum and it has helped me more than once, but I am a new member. So to start, hello to all of you:-)

I am having the somewhat typical rear AC problem in my '01 Excursion 7.3. Front works well, rear blows luke warm. I have checked all the blend doors, front and rear and all the actuators and they are all working properly. (heat/cool, panel/floor) I re-adjusted the air gap and that is good. I have the rear panel out and removed the ducting so I could see the rear evaporator and heater core and they are clean. Front evaporator is clean as well. So I think it is pretty much narrowed down to the actual AC, not ducting/blending. I see that alot of people think it is the rear thermal expansion valve. Is there a way to check it? What I think is the output line going to the evaporator is ice cold, the return line from the evap is slightly cool, and both the lines going out the bottom of the TXV (heading back to the front) are slightly cool. The TXV itself is very cold. It seems like it is not the problem as the line going to the evaporator is cold meaning the valve is open, correct?

This is my first time working with AC before so excuse my ignorance! Any help would be greatly appreciated!

I can post pictures if it is helpful.

Thanks!
Mike

 

Funny thing is that my 2005 is exhibiting the same symptoms as yours. I have not checked the blend doors or ducting like you have yet.

In the past, the problem was not enough heat in the rear and in that case, it was a bad blend door actuator motor.

Sorry, you are are ahead of me on this de-bug. I'm hopeful someone can chime in and help us both...

 

Here is a picture of the TXV with the lines marked: (After running AC at idle for about 10 min.)

 

Just a little bump for the OP. I'm curious also.

 

So today I pulled the rear plenum off again and ran the AC with the fan unplugged. The rear evaporator is nice and cold, so I know I have circulation and the TXV should be good. I also checked the heater core while I was in there and it was so warm that I put a loop in the heater line so it is no longer functioning. I will hook it back up in the fall.

The rear heat/cool blend door left the bottom inch or so of the heater core open for the cold air to flow through, so I elongated it by about an inch with flexible plastic so that it can still open and close easily. I also insulated the AC lines under the hood. Not sure how much good that will do, but it shouldn't hurt.

It am pretty sure the rear is blowing colder than it was, but I did not check temps so I cannot say for sure. It may just be because I want it to so bad!!! It is still just cool, now where near as cold as the front. (which works awesome by the way!)

 

My 02' is the same way. It seems to be a pattern here...

 

Are the heater core lines hot? If so the a/c is fighting the heater. Check the under hood water valve

 

Yes, the heater lines are hot, but like I mentioned in my previous post I dis-connected the rear heater core so that is no longer an issue. I put a manual valve in the water line instead of the vacuum controlled valve that no longer worked.

 

Yep i read right through it I need to read twice before my hands type

 

Anyone have an idea? I am heading on a trip to CA on Tuesday and will have have passengers in the rear. It would be really nice to have it up and running!

 

Just did a crash coarse to test thermal expansion valve pour warm water over it and see if flow increases and cools more if so the txv is ok

 

May be worth a shot see if it changes I know you say it's cold but maybe not enough. Since your inside to truck i would try a blow dryer so you don't have to try and catch the water

 

Will do! I'll let you know what I find.

 

I put a blow dryer to the TXV and it didn't change anything. If anything the air got warmer. I just put everything back together as I am out of idea's right now.

Keep the thoughts coming!

 

Hmm well I wish I could be of more help but since I'm installing my rear heat as we speak I cannot do any trial and error testing to help