I have 2008 ford explorer, i have a problem with the thermostat. It was working perfectly fine but i just recently turned the heater on and after that i switched it back to A/C and now the A/C doesnt.

If the A/C isn't working what does that mean? Is it still blowing hot air? Does the compressor come on? Does the blower work? Sounds like your problem is not with the thermostat as it was blowing hot air before. The probable cause is the door under the dash which opens and closes allowing hot air into the interior is stuck in the open position. Try this. Turn the knob on the dash to the blue area which should shut off the heater diverter allowing hot water to flow into the heater core. Wait a few minutes and see if the air gets cooler. Your problem is not in the thermostat.

May be a blend door issue as OJ says. I agree, it is not the thermostat. Do you know if your A/C compressor clutch engauging when you turn the A/C on?

No the AC compressor Clutch does not get engaged. It does not get the power at all.

Not engaging and not getting power are two different things. With the ac switch on, check the wiring connection to the compressor to determine if you are getting current. If you are, you may be low or out of refrigerant. The compressor will not engage if refrigerant is low.

Thanks OJ, I switched on the A/C and found that the current does not flow to the compressor. That is the reason the clutch does not get engaged. I tried fiddling with the A/C switches by making it on/off number of times but no +ve results. Kindly suggest if I make the engen run and switch on the A/C and directly connect the compressor to the Battery power to isolate the problem. If I get a wiring diagram of the AC system I might be able to diaganose the problem.

OK. Check that you are getting current to the low pressure switch on the dryer/receiver/accumulator. It's the silver colored large beer can looking thing usually bolted on the passenger side near the firewall. It will have an a/c refrig line going to it. Check you are getting 12 volts to the plug. I do not know which colored wire carries the voltage, but it should not be hard to figure it out. Check around and determine how much pressure is required in the "receiver" to activate the switch and use a/c pressure guages to ensure you have enough pressure to close the circuit. If enough pressure is present you can jump relay from there to the compressor. If you do not have current to the switch/relay the problem may be in the controls. I have taken for granted you have checked the fuses.

Please clarify something from your original post. You stated you have problems with the thermostat. The thermostat under the hood has absolutely nothing to do with the a/c system. Did you change the thermostat under the hood? If you did you could have possibly damaged the the wires from the low pressure switch on the dryer/accumulator to the compressor, if they are routed in that area.

Thermostat problem was for some one else not me.I think the post got mixed up. Yes all the fuses are fine. How can I confirm that the gas pressure is ok or not ok. Can i do it by shorting the two thermister wires by jumper and checking if the A/C give out cold air. i mean for a short time temporarily.

You can do it with a set of a/c guages. I've owned three v6 explorers. When doing repair work, and after pulling a vacuum, all it usually takes is about 3/4 can of refrig to allow the compressor to come on. The low pressure switch has a function. When low on refrig it prevents the compressor from running so it does not burn itself up. If you want to jump start the compressor, do it so if it kicks in, you can immediately disconnect it to avoid damage to the compressor. Forget about cold air at this point. Once you get the compressor operating properly cold air should not be a problem. Your problem is getting power to the compressor at this point. Bypassing the low pressure switch rules out compressor problems if it begins running.

Before you do anything, verify you are getting power to the lower pressure switch on the accumulator as I mentioned previously. If you are not getting power to that point the compressor will never start.

Thanks a lot for your help.I checked the lower pressure switch on the accumulator. It does not get the power. Engin was running the AC switched on . No power found on the low pressure switch. What should I check next. If someone can help me with an electric circuit diagram it would really help.

Haynes manuels for your year of explorer have a/c electrical diagrams in them. You may be able to pick one up at auto zone. I checking one I have for a 2003 model. Question: Do you have power to the switchs on the dash? Does the blower work even if the compressor doesn't. The diagram for the 2003 indicates the compressor will not turn on if the blower motor is not turned on. You should have an indicator light somewhere around the a/c controls that glows when the a/c is on (probably amber). For the 2003, there are actually several fuses (maybe 6) controlling different aspects of the a/c system. Check to make sure the fan operates at the various speeds. The blend door actuator moves, and air can be diverted from the floor, to the cabin, to the dash for defrosting. If those items work, you can eliminate about half of the circuitry in the diagram. I would suspect the a/c schematic is similar for your vehicle.

Thanks OJ, When I switch on the AC the blower works fine in different speeds. AC indicator lights on . Everything works fine for the front and the rear one. Speeds of the blower work fine. I am in Saudi Arabia and can not get hold of any document carrying the circuit and that is the reason I request for help.

OK. The Haynes manuel for you vehicle can be purchased on-line from Haynes and downloaded. That may solve the schematic problem. Keep in mind I an referencing a 2003 explorer with the following. If everything is working inside the vehicle, you can eliminate five of six fuses controlling the a/c. The 40A fuse basically controlls everything else. You have numerous relays controlling the clutch etc, plus the compressor on that circuit. I suggest since service is probably scarce in Saudia Arabis, you attempt to jump 12 volts to the compressor to see if the clutch engages. Even with the engine not running you should hear a click when power is applied.

I gave a direct supply to the clutch from the battery as advised, it did work and I could see the movement and hear the click. I checked the relay for the AC it is working fine and has a good connectivity for the switch. I dont know about the switch which indicates AC on on the dash board does it really work or just gives false indication? Do you have any otherr suggetion. I am an Electronics and Communications Engineer by profession and that is the reason I have interest to solve the problem myself..Thanks for your help

Again, from a 2003 explorer as per a/c electrical. Probe backward for power. From A/C compressor to A/C cllutch solenoid. Check solenoid. From clutch solenoid to splitter to junction. 1 leg goes to ac indicator light, other to ac clutch relay. Check relay. Locate A/C pressure cycling switch and A/C high pressure switch. Check there. These two go to the power control moduel (PCM) probably located on the back firewall.

Dry downloading the Haynes Repair Manuel for your year and model. You can print the diagram and the other sections of the book will probably tell you the location of the switches/solenoid etc. I'll continue

According to the 2003 diagram, the a/c clutch relay is located inside the battery junction box. The clutch solenoid, cyclining pressure switch and high pressure switch should be close to the compressor. Maybe.

I have internet in the office only and the downloads are restricted. Where can I locate the clutch solenoid and the splitter. I could not understand " 1 leg goes to ac indicator light, other to ac clutch relay" which part were you refering to. What is the power control module. If I send you the picture can you tell me which one

First. We're actually getting a lot ahead of ourselves. What should be done first is use a set of a/c guages connected to both the high side and low side and determine what the pressure is inside the system without the engine running. Some things can be determined from that reading. Do you have access to a set of guages? Using the guages to read the pressure is not difficult, screw them on and note the pressure, in PSI please. Secondly, just for information purposes for now, it appears from your photo that your PCM is located directly next to the silver a/c accumlator. It normally has several wiring hornaces plugged into it. Do not fiddle with it for now. A lot of other things will have to be checked first. You must also remember I am unable to locate a free on line diagram of the a/c system for your vehicle, I have the book for a 2003. Keep that in mind. I will get back to you a little bit later with a GENERIC way to test the clutch relay and clutch solenoid with a tester.

OK. I'm loosing track of where I am at. We know the clutch is operating, we get the click. Do the following after using gagues to make sure the system has sufficient charge for operation. If it does do the following and get back. With the engine running, ac set to on max, thermostat set to cold (usually blue on dial) and blower inside the vehicle to high. Blower should operate. Remove the electrical connection from the compressor and using a meter capable of reading 12 volts check to ensure twelve volts are being supplied to the compressor. If voltage is present the relay is operational. If not the relay is probably (not definitely defective. Remember, if the system does not have enough charge the compressor will not come on. Trace the wires from the compressor back to the relay. Maybe on the firewall or fenderwell. Don't know. That is usually where they are. Continued below.

The following is generic to most vehicle. Unplug any relay terminal wiring with the inter a/c controls in the off position. Check all wires(most often three) with the test light and the engine running. All the wires should be dead. With engine running and controls to on check all wires again. The wire from the inside panel should be hot, but not the ground or or the wire leading to the compressor. This is to determine if the controls inside the car are working. Plus the relay back in and test again at the compressor. One should be hot. If not, the relay is not sending current. If sending current then the a/c clutch is bad. With the engine running and controls on bypass the relay with a 12 volt source. If compressor kicks in and functions the relay needs replacing. Let me know.

Thanks OJ for all your help and concern. I have been trying hard to solve the issue. I could not come to any conclusion earlier but now It seems we have the answer. I was testing the wrong pressure switch for connectivity and it was also difficut to see if the pressure switches were in short position. I had tried it earlier also but today I tried to short the pressure switch for a longer time incidentlly and the clutch got engaged. It needs some time for compressor to work which I did not know and I was scared to put a short for a longer time. I went to one workshop to charge the gas but it seems the pressure of the gas is low. The mechanic recomendid that we need to do the leak test before charging and as it is late he would do it tomorrow in the afternoon. Here weekend starts on Thursday as you must be knowing. I dont know if the leak is there where could it possibilly be? do you have any recomendations. I once again thank you for all the help. I will let you know tomorrow the status. I am sure by the grace of God and your help it will work tomorrow.

You vehicle is relatively new (2008) for any positive leak points. I have a '96, 99, and 2003 explorers. The two older ones have been ticking along since new with new problems. I have to change the evaporator in the 2003 recently, developed a leak. Whatever requires replacing, you should replace the accumulator at the same time. The colored leak detector which is flourscent works well, but you need a black light and special glasses to to see it. The gas detector is best. It will give off an audible siren type whale when the coolant is detected.

I had gone to the mechanic and he developed vacuum in the circuit and found a hissing sound inside the dashboard and told me that the evaporator is leaking and needs to be changed. It has turned to be expensive affear. I dont know how to remove the evoporator. I was thinking of changing it myself and letting the mechanic test for the leak and charge the refregent only. Can I have some guidence as to how to proceed in changing the evaporator.

Certainly. Probably next to your accumulator (silver coffee can looking affair you posted as a photo yesterday). There is a aluminum tube comming out of the accumulator (screw on) which goes to the exaporator. The evaporator is within a plastic box which protudes from the back firewall. It may be covered with silver looking material. It should be put together like a clamshell. Maybe a couple of screds along the top, and a couple of more down the side, and maybe bottom to hold the clamshell together. Remove the fasteners and spread/remove the shroud covering the evap. It looks like a small radiator maybe a little larger than a cigar box. Once the pressure lines are unscrewed there may or not be a fastener mounting the evaporator to an object. Installation is the reverse, Not difficult at all. - continued

I do not know the EAP rules in Saudi Arabia. I hate to see you locked up because coolant was released into the atmosphere. But, since the evap is leaking, I doubt you have any refrigerant left in the system. You will have to replace the accumulator in the process, always change the accumulator. After putting everything back together, give me another ring and I'll instruct you on the charging procedure. - continued

To give you an idea of the cost in parts I did a little checking. In the US - at autozone the accumulator will run about 50 bucks. The evap core is about 110 dollars. I haven't checked on the refrig capacity, but my 2003 took a little over one lb of refrig One can plus a little more.

Do I need to remove the airbag. And also do I need to remove the ac/heater box to reach the evaporater.

I'd disconnect the battery just be safe concerning the airbag. As I stated previously, I am working from what would have to be done in my 96, 99, and 2003 to remove the evap. The evaporator is one piece separate and apart from the heater core. The evap core should be accessible from under the hood, attached to the firewall, and within a box. From the photo you supplied, it appears the line from the accumulator to the core runs from the right from the accumulator. Trace the line to to the core.

I am trying to open the instrument panel and I could locate the bolts as shown in the picture. I have loosened them to some extent to confirm that they are the right ones I have to open but I feel there are some more hidden bolts which I cant see on the lower side of the panel. I know you are trying your level best to help me for which I am very thankful. I checked the prices with Ford dealer on the phone. Evaporater $ 173 and Accumulater $101 I have not seen the Evaporater that is in the vehical as I did not take it out yet. I wanted to reconfirm its uselesness. Do you think there are any chances of it getting repaired or you think it should be changed once it has given the problem. How long does the evaporater normally last. Thank you

It would appear you have located some instructions or diagram which states the evaporator cover must be unbolted from inside the vehicle. Sobeit. I have yet to see one come apart that way as my three vehicles are from 96 to 2003. Once you get the evaporator out of the vehicle, and if is leaking, you will notice it looks like a small aluminum radiator. At the location of the leak, or on the bottom of the fins you see what appears to be oil. That is what it is, oil that is within the system to lub the compressor. The presence of oil signifies the leak. And no, you cannot repair it unless you can weld aluminum and pressure check it after. Evaps, for the most part, are not rebuilt. They are melted down and recast. As to how long they last, who knows. Aluminum corrodes which causes the leak. The a/c in my 96 has all the same parts as it did when it came from the factory. It still blows cold as ice. Same for the 99. I changed the evaporator in the 2003 about a year ago because it developed a leak.

If you can access WWW.autozone.com you can see a photograph of the evaporator as well as the accumulator. I did a little checking and learned the evaporator for your vehicle fits 2008 through 2010 both v6 and v8 models.

Seems the mechanic you spoke to previously verified the uselessness of the evaporator. There are two ways to determine the core is leaking. One is with an electronic lead detector which detects (squells) at the presence of refrigerant. The second is a combination of no pressure in the system and an accompanying visable oil stain on one of the components under the hood. If there is no pressure in the system, and no visible oil under the hood on any related parts, the leak has to be in the core which is not viewable unless the cover is removed.

I change evaporator of ford explorer 2008 now AC if working but compressor not cutting off and i was unable to find thermostat of evaporator aswell can some help. Thanks

I have developed a new problem, the compressor clutch looses power due to which AC gets disconnected and connected frequently. When it is connected the cooling is very good. I ashed few peope and they concluded that the computer has gone bad. I need your suggestion as to what needs to be done. Appreciate your help

to GuruCS5WC I change evaporator of ford explorer 2008 now AC if working but compressor not cutting off and i was unable to find thermostat of evaporator as well can some help. Thanks i do have the same exact problem, compressor not cycling off and just keeps running.. i spent a lot of time searching for the cabin temp sensor but never found it and i really not sure if it is the cause for my issue or not! and also i've seen people bypass the faulty sensor, "which means continuous operation" and the compressor cycles normally. any information would help me figure out this puzzle? what exactly controls the cycling of the compressor on this 2009 4.0L explorer..? thanx