1988 MK VII AC no work!!

[Gray Mist]

I've traced out the wires as best as I can without any wiring diagram. The AC compressor has power but doesn't run. I hear a clicking (sounds like relay) on the driver side strut tower and the idle goes up and down with the clicks. I jumped both + and - wires to compressor and it runs and makes cold air.

Anyone care to share some ideas? Or better yet ...anyone have a copy of the skematics for this car. 1988 Lincoln MK VII Bill Blass edition.

Thanks

 

[OldSchool1]

I've traced out the wires as best as I can without any wiring diagram. The AC compressor has power but doesn't run. I hear a clicking (sounds like relay) on the driver side strut tower and the idle goes up and down with the clicks. I jumped both + and - wires to compressor and it runs and makes cold air.

Anyone care to share some ideas? Or better yet ...anyone have a copy of the skematics for this car. 1988 Lincoln MK VII Bill Blass edition.

Thanks

Sounds like a high or low voltage problem.

How is your voltage regulator?

 

[JoshMcMadMac]

Just to be sure, do the EATC self-diagnostic to see if it throws any codes.

 

[One_Way]

Is the A/C refrigerant fully charged? If not, the AC compressor will NOT power up, or will only click on and off very quickly.

Make sure the AC is fully charged up before you trace electrical problems.

 

[Gray Mist]

I should have been more specific about info. Low pressure switch has power to both sides. This leads me to beleive that there is sufficent freon to run. There is power to the compressor clutch. but it doesn't run. The clicking sound is coming from a cover conglomerate of things on the left strut tower (not the AC clutch. It doesen't do anything.) If I unplug the clutch and run jumper wires from the battery to the clutch it runs and makes proper cold air. Seems like the problem must be on the ground side of the compressor clutch wiring.

How do I do a EATC diagnostics?
NO Manual....would pay $200 for a factory manual for this car.

 

[OldSchool1]

...
NO Manual....would pay $200 for a factory manual for this car.

The good guy in me says, "Tell Gray Mist that the high end for a 1988 shop Manual is $80.00 - $140.00"

The SOB in me says, "Tell gray dude that you'll sell him one for only $100.00."

True shop manuals from Ford Publishing run $40.00 to $140.00 The EVTMs are way less.
See:
http://www.ebay.com
http://www.faxonautolit.com/

I don't own the 1988 but you could ask if anyone in your area has one that you could borrow.

 

[Gray Mist]

Thanks OldSchool! Thats all it took was to put an outrageous offer out there that I would have paid just to get the books. I've searched for over a month since I bought the car and watched Ebay with no sucess. I love the car and plan to enjoy its potential as well. With only 34,000 original miles, I have a great starting point. But with out the books it was annoying.

Thanks again.

 

[JoshMcMadMac]

To initiate the EATC self-test, simultaneously press OFF/AUTO and DEFROST, release and press A/C (or possibly VENT like I have in my car) within 2 seconds. Record the number provided.

 

[Gray Mist]

AC still no work.

Josh..Thanks for the info. Still haven't gotten around to doing test. Been riding with windows down and enjoying my 24 MPG.

However...does anyone know if this car has a "Constant Control Modual Relay"?

I read on an AC forumn that fords had a problem with them messing up. Also that they are located on the drivers side strut tower. Which is exactly where the clicking noise comes from in my car.

Just doing all the diagnostics from the lazy position.

Thanks

 

[OPNHOUS]

To initiate the EATC self-test, simultaneously press OFF/AUTO and DEFROST, release and press A/C (or possibly VENT like I have in my car) within 2 seconds. Record the number provided.

Is it possible for you to post the codes that can come up and what they mean?

I haven't had AC since I bought the car last Summer and I am already looking at an ABS problem that needs my attention first. If I could narrow down the AC isues easy that would take a load off and let me concentrate my attention on the ABS issue(constant ABS light after being intermittent).

Thanks in advance for you help.

 

[JoshMcMadMac]

Is it possible for you to post the codes that can come up and what they mean?

I haven't had AC since I bought the car last Summer and I am already looking at an ABS problem that needs my attention first. If I could narrow down the AC isues easy that would take a load off and let me concentrate my attention on the ABS issue(constant ABS light after being intermittent).

Thanks in advance for you help.

Hmm, I know there are 8 codes that can come up on the EATC. If you want to post what code you get I'll look it up for you. Also a code 88 means no issues.

 

[Gray Mist]

Getting to hot to not have AC

got my manuals today so I started tracing problem.

With AC on and car running the AC clutch doesn't engage (though it has power and/or runs when I jump both wires from battery and makes cold air) The WOT relay on right shock tower clicks on and off and the idle goes up and down a bit with the clicks, but cluthch never engages. Diagnositic test comes up with a 88. Best without tearing into it the books seem to be leading towards electronic control assembly.

Any helpful thoughts?

 

[JoshMcMadMac]

I'm still leaning towards the pressure switch and low coolant. Pull the pressure switch and use a paper clip to jumper the connector. Turn the car on and set the AC on high at 60. With this the compressor should cycle. Either way you have narrowed down your issues.

 

[OldSchool1]

I'm still leaning towards the pressure switch and low coolant. Pull the pressure switch and use a paper clip to jumper the connector. Turn the car on and set the AC on high at 60. With this the compressor should cycle. Either way you have narrowed down your issues.

I'm not sure if it will cycle at 60 degrees F.

 

[JoshMcMadMac]

I'm not sure if it will cycle at 60 degrees F.

It depends on the outside ambient temperature. I know how you love to learn about these cars, so...if you go to the air conditioning section of the service manual there is more information on this. I cannot remember the section off of the top of my head, but I think it is section 33 in my 1989 service manual. The first several pages address how the AC system works, and has graphs showing cycle times against ambient temperature I believe, along with other graphs. I have a pretty good knowledge of the "engineering aspect" of HVAC systems and thermodynamics, so I can probably explain most of it if you have questions.

 

[Gray Mist]

AC stuff

Josh....There is power to and through the low pressure switch.
There is power to the compressor clutch.
If I jump the the power and Ground from the battery it makes good
cold air.
Outside air temp is in the 90's, I have temp set at 72.

The WOT relay circut is tied into the problem. At Wide Open Throttle the engine control unit shuts the compressor off. It appears it does this by intrupting the ground side of the compressor circut.

A new control unit is $260.00 plus $100.00 core deposit. I'm looking into bypassing the WOT relay.

 

[OldSchool1]

...
I know how you love to learn about these cars, so...if you go to the air conditioning section of the service manual there is more information on this.
...

You're making my head hurt again.

I'm just learning the system for my 1984 so I'll have to pass on this "preffered reading" 1989 item for now.

I agree with you about the head unit tests though.

 

[OldSchool1]

...
A new control unit is $260.00 plus $100.00 core deposit. I'm looking into bypassing the WOT relay.

Gray.
Have you gotten around to that head unit test yet?

That would have been my first or second test.

 

[Gray Mist]

The A/C she works!!!

OK.....Oldschool... I really hate to go over this however.......Months ago I assumed it was just low on freon 12, so I took it to a local place (because they won't sell 12 to me at auto parts store) and the mechanic SAID that there was power on both sides of low pressure switch, and that there was power to compressor. Today I decided to get down to it and fix it, so I started from scratch. Well there wasn't power to both sides of switch but if you jumped compressor wires it made good cold air. So I hooked up guages (low sided only just to see), jump low switch and at idle it was pulling down to 38 and making cold air. Low side switch I thought just fed power to compressor.....wrong ....low side switch interupts ground from compressor. SO a $26.00 switch and "SHE MAKES COLD AIR".

Just shows to go ya.....if you want it done right don't trust anybody.....do it yourself!

Thanks for everyones help and interest. AND sorry for your headache Oldschool.

PS: why doesent the manual have a full set of schematics?????

 

[OldSchool1]

FANTASTIC!

The A/C she works!!!

OK.....Oldschool... I really hate to go over this however.......

We sincerly want to know because, I'm sure that there are at least a dozen people here without A/C.

Months ago I assumed it was just low on freon 12, so I took it to a local place (because they won't sell 12 to me at auto parts store) and the mechanic SAID that there was power on both sides of low pressure switch, and that there was power to compressor.

Yup. 97% of our car breaks ground instead of hot. Real easy to have a power drain or short something while working without disconnecting the battery. I'm ~really~ glad you pointed this out to people.

Today I decided to get down to it and fix it, so I started from scratch. Well there wasn't power to both sides of switch but if you jumped compressor wires it made good cold air. So I hooked up guages (low sided only just to see), jump low switch and at idle it was pulling down to 38 and making cold air. Low side switch I thought just fed power to compressor.....wrong ....low side switch interupts ground from compressor.

See above

SO a $26.00 switch and "SHE MAKES COLD AIR".

Now, we really need that part number and weather or not you got it from a Ford dealership or Autozone.

Just shows to go ya.....if you want it done right don't trust anybody.....do it yourself!

ONLY when we have great Owners like yourself to help guide us through what the heck we should be looking for; what is a normal condition across what points and what is an abnormal condition across what points and what should be our next step once an abnormal condition is met. Trouble shooting in our shop manuals is laid out JUST like that.

Thanks for everyones help and interest. AND sorry for your headache Oldschool.

Nawww. We all thank YOU for giving us one more bit of knowledge about the best American made luxury sport coupe from 1984 to 1992!

PS: why doesent the manual have a full set of schematics?????

You're looking at the wrong manual
Check out this one :

 

[JoshMcMadMac]

Glad to hear that you got it sorted out...do I get to say I told you so now?

 

[Gray Mist]

I was waiting for that!

Josh... you were right but for the wrong reason. But go ahead and chalk up "I told you so"

Thanks again.

 

[Gray Mist]

Oldschool..... I have that manual also. It's just not the same as the old style where there were foldout pages that had every wire, plug and component on one large page. I would have sorted it out easier with that format.

Guess I showing my age on this one......

Switch was bought at a local auto parts store, no big deal. I just asked for a low pressure cutout switch.

 

[Gray Mist]

Ps

Switch was simple to replace. Just hand tight, so it came right off and didn't require discharging freon.

 

[OldSchool1]

Cool and cool.

Glad you got the problem worked out. Before replacing my switch, I discovered that the 1984 had about ... 2 ounces of pressure in it Can you say vacuum pump? I've spent my July allotment of "toys money" so I may get the vacuum pump in August and clear the system.

Speaking of age, this is what I listened to in High School:
# 1 My Sharona - The Knack
# 2 Bad Girls - Donna Summer
# 3 Do Ya Think I'm Sexy? - Rod Stewart
# 4 Reunited - Peaches & Herb
# 5 Hot Stuff - Donna Summer
# 6 I Will Survive - Gloria Gaynor
# 7 Escape (The Pina Colada Song) - Rupert Holmes
# 8 Ring My Bell - Anita Ward
# 9 Babe - Styx
# 10 Too Much Heaven - Bee Gees