A/C intermittently cools when idle but always when moving

[mxc0bbn]

If this has already been answered please point me to the thread. I could not find one with these exact conditions.

The situation is as follows:
I have a 2010 Expedition Limited 2WD. When I start the ignition with the A/C on it may or may blow cold or warm air. When I start moving though the air starts to cool and then warms up when I stop.

A couple of times when this has happened I've stopped, opened the hood and noticed that the two fans on the radiator are not functioning. Sometimes I press the A/C button on the dash to turn it off then press it again and the fans start up (and the air is cool). Other times this does not work.

When driving along I can also hear a hiss coming from inside the cabin at the rear. I can't tell which side it's coming from but it sounds like the driver's side.

I have not taken it in for service yet because the first service person I asked about this (without them even looking at it) said it was probably the compressor...And since I don't believe in psychics, this guy was most likely trying to jack me for a new compressor no matter what the problem really is.

It has been going on for about 6 weeks so I can almost assume that it's not (necessarily) a freon leak because if it was it wouldn't be as cool at this point when it does cool due to the lack of freon. I have also checked to make sure that the compressor does cycle on and off when the A/C button is pressed. It has done so every time I've tested it (at least 5 separate occasions).

I have also checked all the fuses in the area under the hood that have anything to do with A/C, Climate Control or fans. The ones where you can see the fuse wiring (clear) are all ok. The ones that are black boxes (relays?) I can't tell.


At this point I'm open to suggestions that would help me narrow this down. I'm open to fixing it myself if it's a simple fix, but I'm also willing to take it to the dealer. I would just like to have an idea of what it is (or isn't) so that when I'm there I can refute the service guys' claims of "oh you have a really big (and expensive) problem here".

Thanks,
Mike

 

[toms89]

The a/c needs air flowing through the condensor (a/c radiator) to function properly. If you are saying there is no airflow across the condenser when you are stopped due to the fans not running that sounds like your problem. Why would be the next question.

Sorry not familiar with the 3rd gens so really do not know your set up.

The hiss you hear may just be the freon flowing through the lines. Compressor may be kicking on and off for what ever reason.

 

[stamp11127]

In addition to what Tom has posted, if it is just the fans not working, you should have "normal" cooling at highway speeds whether they are on or not.

 

[mxc0bbn]

In addition to what Tom has posted, if it is just the fans not working, you should have "normal" cooling at highway speeds whether they are on or not.

I do (at highway speeds)....

And toms89:
I also think that this is the problem, but I'm not sure if it's the fan relay or something else.

Thanks for the info...I guess with this info I can at least dispute if the service department tries to tell me something else is the problem.

If it is the fan relays how much can I expect to pay to have it replaced at the dealership?

 

[stamp11127]

Don't go to dealerships for the little things. Look at the fuse/relay box in the engine compartment. There should be an indicator of some sort in the lid as to what is what. Pull the one labeled cooling fan or similar, head to your local auto parts store for a replacement. Relays are rated by current load they can handle and the number of connectors.

For a good name brand relay I would expect to pay under $20 retail.

If you want to diagnose prior to buying a relay, the group of us here will help you with auto electric 101.

 

[mindgame]

How about this...

At idle.. does your fans cycle on and off at normal temp?
turn on A/C.. does atleast one fan (if you got duels) turn on?
If not.. then there is the problem..

When the fans kick in, the pulled air will cool both the condensor and radiator.. When it cycles off.. a/c starts to get warm..

 

[FordCustSrvc]

...I have a 2010 Expedition Limited 2WD. When I start the ignition with the A/C on it may or may blow cold or warm air. When I start moving though the air starts to cool and then warms up when I stop...

Hi mxc0bbn,

Keep me posted on whether or not you decide to return to the dealership. I'm happy to step in and see how I can assist; I'll just need a PM from you with your VIN, dealer, mileage, daytime phone number, and full name.

Thanks!

Crystal

 

[01yellerCobra]

Are your electric fans from the factory or aftermarket?

Edit: Nevermind. I just did some quick research. It sounds like a sticking relay for the fans. Cycling the power gets it to move. Look under the fuse panel, a lot of times there's more then one of the same relay. You might be able to swap another relay into the place of the fan relay to see if that fixes the problem.

 

[mxc0bbn]

Ok, so I did a little more testing and here's what I have so far:

At this point every time I start up the vehicle (with A/C on) it blows warm air. I turn off A/C wait 5 seconds, turn A/C back on and I start to get cool air. I have not looked under the hood every single time I've done this but the 2-3 times I have looked I noticed that the fans were not running until I cycled the A/C.

Something I've been watching for that I haven't seen is high engine temp. I haven't seen engine temp move from its normal range so I gotta figure that at some point the fans (dual fans) are coming on to dissipate Radiator heat.


To answer some questions:

At idle.. does your fans cycle on and off at normal temp?
turn on A/C.. does atleast one fan (if you got duels) turn on?

The times I've looked under the hood both fans have been off and then both come on when I cycle the A/C

It sounds like a sticking relay for the fans. Cycling the power gets it to move. Look under the fuse panel, a lot of times there's more then one of the same relay. You might be able to swap another relay into the place of the fan relay to see if that fixes the problem.

This sounds pretty reasonable, the only problem is I don't know which relay might be bad (which also goes to stamp11127's post). If I understand correctly, relays are the ones in the under-hood fuse box that are solid black, square and bigger than the clear plastic fuses correct?


Anyone have any idea which fuse/relay number I should be looking at? I looked at a few but couldn't tell if they were good or bad just by looking at them...

Thanks,
Mike

 

[01yellerCobra]

Ok,This sounds pretty reasonable, the only problem is I don't know which relay might be bad (which also goes to stamp11127's post). If I understand correctly, relays are the ones in the under-hood fuse box that are solid black, square and bigger than the clear plastic fuses correct?


Anyone have any idea which fuse/relay number I should be looking at? I looked at a few but couldn't tell if they were good or bad just by looking at them...

Thanks,
Mike

The fans might be coming on when commanded by the ECU. Which would keep the engine temps in check.

Yes, the relays are the square box looking things. Look in your owner's manaul. There's usually a list of the fuses and relays in there.