OT: Auto AC Help Needed

Danny in CO

Well-known Member
I have a 1998 Ford Escort. The AC has work great until Tuesday morning. On my way to work I had the AC on and it was too cold. I turned the AC off. After about 20 minutes I turned it back on. No cold air. I checked and the compressor is not engaging. I have checked the fuse and it is good. There does not seem to be any kind of relay under the hood. There is still pressure he the AC lines. I checked the connection on the compressor. Still connected.

Any ideas what is wrong? It is supposed to be nearly 100 here in Colorado today. I need AC!!

Thanks for any help,
Danny
 
Apply 12v directly to A/C clutch & if it licks in or doesn't, you will know if it is in control path or compressor clutch. Then move on from there.
 
No, it was a cool morning and I didn"t need the AC. As the sun came up, it warmed up and then I did need it.

Danny
 
It should have a Low Pressure Switch in the system. If the Freon charge is too low the Low Pressure Switch opens and will not allow the compressor clutch to kick in.
 
I had a/c trouble on a Crown Vic and the tech trouble shot the compressor by bumping clutch with a 1.5" x 2.5' stuck and told me the clutch was not engaging. Symptoms were intermittent a/c cooling. Lucky for me the shaft was damaged during clutch removal and the compressor had to be replaced. The tech warned me this could happen thanks to Ford's excellent design. Once the system was replaced I was cool.
 
The low pressure cut out switches fail in the open position quite often. I guess the contacts go bad. Unplug harness from switch and jump across plug with a wire or even large paper clip, see if compressor cuts in. Have engine running and A/C controls on. This is assuming you have enough charge to have the switch kicked in. Switch is closed but not passing current.

You can change Low pressure switch without dropping the refrigerant charge, it has a Schrader valve behind it. Have had to change two in the past year, on different vehicles.

A rule of thumb that I go by to see if you have close to proper charge is with system running, the suction line should be cool and 'sweaty' all the way from evap outlet to compressor. A set of gauges helps also! This is just one thing to check.

Garry
 
(quoted from post at 06:30:14 06/28/13) I had a/c trouble on a Crown Vic and the tech trouble shot the compressor by bumping clutch with a 1.5" x 2.5' stuck and told me the clutch was not engaging. Symptoms were intermittent a/c cooling. Lucky for me the shaft was damaged during clutch removal and the compressor had to be replaced. The tech warned me this could happen thanks to Ford's excellent design. Once the system was replaced I was cool.

I am going to assume he broke the snout the clutch coil presses onto... For the record they are all that way its not a ford thang...
I have broke one once I figgered it out have not broke another but its always possible if you get in a hurry... Its always a roll of the dice to replace just the compressor clutch,, Its somewhat a roll of the dice to replace just the compressor... The expansion tube needs to come out for inspection it will tell the story...

The unanswered question is what got the clutch... Did it ware out are is the compressor failing and over working the clutch...
I will not warranty a clutch replacement only its your crap shoot not mine... New compressors with clutch assy are not much more than a new clutch assy... If you can not afford to fix it right the first time I can not afford to fix it under warranty either...

If you are gonna replace the compressor take the old one apart if its tearing up theirs a good chance your new one will also if you do not replace the AC lines, hoses, condenser and accumulator...

Its hard to bite the bullet and go for the kill but repeated compressor failers are hard to eat also... If you do have repeated compressor failers you are gonna get to replace the lines, condenser and accumulator anyways :twisted:

When the receiver drier is tween the compressor and condenser it will trap most contamination,,, When GM went to the R4 compressor clutch cycle set up and others followed suit it changed the way AC were serviced... Now the filter is on the discharge side of the evaporator so all the contamination gets to travel threw about the hole system...

To shadetree a system charge Blower on HI check the inlet and out temp of the evaporator they should both be cold about the same feel (with you hand) on both sides...

If someone did not explain this to me I would not let them work on my AC they do not know what they are doing they can play dice with someones else's money...
 
(quoted from post at 14:39:12 06/28/13) Thanks! I'll find the low pressure switch and bypass it.

To quote JMOR:

[b:f5e48faa35][i:f5e48faa35]Apply 12v directly to A/C clutch & if it licks in or doesn't, you will know if it is in control path or compressor clutch. Then move on from there[/i:f5e48faa35][/b:f5e48faa35].

TOH
 

So what do you do if the ac clutch relay controls the ground side of the clutch,,, It looks that way to me he better be looking for a wiring diagram....

The relay is in one of those black box's that resembles a EI control module :twisted: ...
 
(quoted from post at 20:41:55 06/28/13)
So what do you do if the ac clutch relay controls the ground side of the clutch,,, It looks that way to me he better be looking for a wiring diagram....

Hmmmm - you test for 12V (presumably) power present at the clutch solenoid and then ground it instead? A wiring diagram is always better than guessing anytime you are trouble shooting an electrical control circuit. A diagram AND a functional description is even better :roll:

TOH
 

AC clutch circuits are like they were in the good old days...

Every thing has to report to the PCM for any reason even reasons that are not AC related the PCM will kill loads and the AC is a big load so it will go for the big unneeded first...

A example would be if the coolant temps were above normal it would shut down the AC in a effort to bring the temps down..
Another would be full throttle are even a load such as Turning the steering wheel to full lock in a parking lot situation... When the PCM sees a high load applied to provide full power are to control idle it may shut the AC down...

It would be rare to see battery voltage at the AC clutch threw all the wiring and switches then add in a well worn clutch a 1 to 1 1/2 voltage drop is the norm...

Theirs nuttin wrong with the way you guys think it may be that simple... It can still throw you a curve ball.... Yes he needs a diagram unless he works on Ford Escorts on a regular basis...
 
(quoted from post at 20:41:55 06/28/13)
So what do you do if the ac clutch relay controls the ground side of the clutch,,, It looks that way to me he better be looking for a wiring diagram....

The relay is in one of those black box's that resembles a EI control module :twisted: ...
OT wanting to get in a whizzing contest with ya hobo (hardly keep from wetting my shoes anyway), but my advice to dan is still good. If it is 'ground controlled', then the clutch connector must have 2 wires, so apply 12 to one and ground to the other. I, too, always like to have a diagram, but don't always & must be more careful then.
 
(quoted from post at 17:20:46 06/29/13)
(quoted from post at 20:41:55 06/28/13)
So what do you do if the ac clutch relay controls the ground side of the clutch,,, It looks that way to me he better be looking for a wiring diagram....

The relay is in one of those black box's that resembles a EI control module :twisted: ...
OT wanting to get in a whizzing contest with ya hobo (hardly keep from wetting my shoes anyway), but my advice to dan is still good. If it is 'ground controlled', then the clutch connector must have 2 wires, so apply 12 to one and ground to the other. I, too, always like to have a diagram, but don't always & must be more careful then.

Its not a whizzing contest I understand were Y'all are coming from and respect Y'all's advice his issue is going to be accessibility as in its well buried...


A quick shade tree test would be to lay a steel bar on the end of the clutch hub (play safe) if it magnetizes the bar when the AC clutch is commanded on the system controls are working... If so it could be a worn/weak clutch assay are a voltage issue... It would be a rare event to see a open AC clutch field coil....

It could be as simple as the air gap needs to be reset...

But my first check would be to attach AC gauges...
:wink:

That does bring up a question "if refrigerant is heaver that air how does it end up in the upper layer of the O-zone"...
 
I'll have to refer you to Al g on that one...we are not on good speaking terms! :evil:

.........and gotta get on with it & do something. Not going to fix itself. YOU WOULD HAVE BEEN DONE & DEPOSITED THE CHECK BY NOW! :wink:
 
Hobo, that is a good one about the ozone layer! I have always wondered that myself. We are always having some scam laid on us.

Garry
 

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