NO A/C

[allgood]

Hello. I have 1997 EXPLORER that stopped blowing cold after an impact. Vehicle went over a median (@8 inches high) at about 20 mph. A/C didnt blow cold thereafter. Compressor doesn't cycle. Ran 12v to compressor, it engaged. Disconnected wire to compressor, started vehicle, put A/c on Max, No Voltage. Took it to Good Year, said System is fully charged, electrical problem.
Can anyone tell me what to do. Fustrating and Hot.

Thanks

 

[Mbrooks420]

First, I’d try swapping relays around. After that, I’d start chasing wiring, and the pressure cutout switches.

 

[allgood]

Thanks, swapped relays, checked fuses. Seem to be in order.

 

[SoHK_alumni]

Auto temp control or manual? Either can fail.

Under hood, PCM, low pressure switch near a/c blower and high pressure switch near battery all control relay for a/c clutch.

Pressure switches pretty easy to unplug and test bypass with bent paper clip. If either have failed, they can be replaced without removing freon from system. There's a valve under each switch that closes when switch is unscrewed.

 

[allgood]

Eatc, I have the buttons to control the settings, not the 3 rotating knobs. Question, how do the settings of the eatc move the blend door. Is it electronic or manual? could a stuck or disconnected blend door prevent the compressor clutch from cycling. When i turn on eatc(press max a/c) then press red button till temp reads 90', an audible clicking from behind the dash cycles 20X then stops. Turned off the car, restarted, pressed max A/C, the clicking started again.

 

[koda2000]

Eatc, I have the buttons to control the settings, not the 3 rotating knobs. Question, how do the settings of the eatc move the blend door. Is it electronic or manual? could a stuck or disconnected blend door prevent the compressor clutch from cycling. When i turn on eatc(press max a/c) then press red button till temp reads 90', an audible clicking from behind the dash cycles 20X then stops. Turned off the car, restarted, pressed max A/C, the clicking started again.

It's all electronic. There is a blend door actuator with a small electric motor inside of it. What often happens is that the plastic gears inside the actuator strip and can't open/close the blend door. The actuator is located behind the glove box, on top of the heater box. Once removed you can take the actuator apart to see if the gears are broken. The blend doors are also known for breaking at the shaft that engages the actuator, but the clicking is indicative of a broken actuator.

Note: The manual and EATC blend door actuators are different and are not interchangeable.

If the actuator is at fault, you can remove the crescent shaped gear from the actuator, stick it on the blend door post and wire it open or closed until you get a replacement actuator.

Whether the blend door is open or closed has no effect on the A/C compressor engaging, the A/C compressor will still function normally, but heat wins out of cold.

 

[allgood]

Ok, so i am dealing with at least two failures. The actuator sends the conditioned air where you want it. Replace it or secure door open/close. (What position do i need for a/c).
Given info above, where would be a good starting point to troubleshoot the compressor.

 

[koda2000]

No, not exactly. The blend door opens a pathway through the heater core. There are other actuators that control air direction. Some are electric and some are vacuum operated.

If you've ruled out a low refrigerant level, pressure switches, A/C relays under the hood and fuses, Google Ford EATC self test to check if it's working properly. There's a compressor relay inside the EATC module that sometimes breaks its solder joint.

I don't recall the blend door open and closed positions, but I think turning the crescent gear counter clockwise is closed and clockwise is open. You can sort of feel when it's closed vs open. In any event you'll find out as soon as the engine warms up. I've drilled a small hole in the corner of the gear to attach a piece of bailing wire to keep it where I want it. Shut for summer, open for winter.

 

[ThreeJs]

Aloha Brah!
I have a 86 EB Explorer.
My AC stopped working a few weeks ago. I'm in Vegas so it's been HOT!
Took to work and had it checked. System was full. No power to compressor or at low pressure switch..Tech said somewhere in the dash. I needed to leave work early that day so I asked if we could just get it to work somehow.
We hotwired the compressor to battery positive terminal and AC works. I've since hooked the AC power wire to a keyed ignition source so I didn't have to keep disconnecting the power wire everytime I parked.

I think it may be the EATC module but will look into it after the weather cools down.

 

[allgood]

Thanks guys, I'm able to look at it the morning. Will post findings.

 

[allgood]

car running , A?C on max,
voltage at low pp switch is 8.7v
voltage at switch in back of compressor is 13.8v
can i test the relay 4 by pulling it, check for voltage at 30 &87a

 

[allgood]

No power to relay.

 

[allgood]

WOT (4) relay removed
pin 30 0V
pin 85 0V
pin 86 12.8V
pin 87A 0V
pin 87 0V
When i jump 86 and 87A compressor engages.

 

[koda2000]

If you think the WOT relay is the problem, just swap it with another similar relay found in the distribution box and see if that makes a difference, or you can install a jumper wire in place of the relay (between 86 and 87A) and have A/C. The WOT relay is there to turn off the compressor when you need max power to accelerate and you can live w/out it.

I believe the WOT is activated by the TPS, so if the relay is okay it might be a TPS or wiring issue. Personally I'd just go with the jumper wire fix. It wont hurt anything.

 

[ThreeJs]

Here's what I did.
Originally the jumper wire went straight to the positive battery terminal next to the compressor.
Now it's hooked to a keyed power source in the fuse box under the hood.

BTW...gonna be around *105 + today.....

 

[koda2000]

You don't want power to the compressor clutch all the time, so I wouldn't do what you've done (besides it looks kinda hokey). Running 12V power to the clutch all the time will may not allow it to cycle (which it needs to do). If your fix is still allowing the compressor to cycle then that's fine. I guess it depends what controls the cycling. Is it the pressure switch or the PCM?.

 

[allgood]

relays good, when jumping 86 &87a clutch engages and stays on. No cycling.
Isn't relay power supposed to be coming from pin 30.

 

[ThreeJs]

You don't want power to the compressor clutch all the time, so I wouldn't do what you've done (besides it looks kinda hooky). Running 12V power to the clutch all the time will may not allow it to cycle (which it needs to do). If your fix is still allowing the compressor to cycle then that's fine. I guess it depends what controls the cycling. Is it the pressure switch or the PCM?.

Is it kinda hokey?...Yes.
Does the AC work when it's 100-110+ degrees out...Yes.

Does the AC compressor cycle?...No.
Is it a permanent repair ?....No, but it buy's time till the weather get's cooler and I have time to delve into it..

I think of it as a "urban trail fix". Like out on the trail. It's not how it looks but whether it works and keeps you going till a repair
can be effected at a later date.

 

[allgood]

would it b ok to run it "jumped" for a week.
Another question, what does the eatc relay re-solder fix? does it have anything to do with compressor clutch engagement, send power to compressor?

 

[Mbrooks420]

With it jumpered I assume the high pressure switch is out of the circuit? If that’s the case I’d surely not leave it.