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1988 Cadillac Fleetwood Diagnosis

Tiny
JRNEAVES
  • MEMBER
  • 1988 CADILLAC FLEETWOOD
  • V8
  • FWD
  • AUTOMATIC
  • 110,000 MILES
My 1988 Fleetwood has an air conditioning problem. When it get cold the air conditioning quits working. I take it in and the GM dealer can't find any problem. When it get warm outside I take it in for repair and they just evacuate the system then recharge it and it starts working again. It will continue to work until it get cold outside again. Any ideas on what can be wrong? Is it possibly linked to some elctronic component or sensor?
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Wednesday, April 23rd, 2008 AT 5:25 PM

18 Replies

Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Is this a manual or automatic system? My software shows both. So if it is cold out and you take it in, they top off the freon and it works?
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Thursday, April 24th, 2008 AT 7:37 AM
Tiny
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In response to the answer to the air conditioning question I submitted yesterday, the transmission is an automatic. And, they do not top off the air conditioning because none has leaked. They just evacuate the system and put the old stuff back in. It is not freon because the entire ac system was replaced and it uses the new coolant, what ever it is. They have dye tested the system and found no leaks. They have replaced the upper and lower sensors. All they ever do is evacuate the system and put the coolant back in, and it works until it gets cool outside again. Nothing is freezing. The place that does the diagnosis and repair is a GM dealership. The ac is under the Goodwrench warranty. I just don't think they know what to do. Their diagnostic procedures do not identify the problem. I am hoping an old time Cadillac mechanic has seen this problem and might know what causes it.
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Thursday, April 24th, 2008 AT 7:56 AM
Tiny
2CARPRO JACK
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Im well aware it is an automatic transmission. I asked if it had an automatic system (set desired temp and let it go) I was using freon as a name, it is 134a. I asked about the auto system because if it is colder outside than the desired setting it wont work. Ambient temp shouldnt effect the operation, If they cannot figure out where the a/c signal is stopping, then yes I would recommend another shop, preferrably a Caddy specialist
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Thursday, April 24th, 2008 AT 4:04 PM
Tiny
JRNEAVES
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I am sorry I misunderstood you. It is an auto temperature system. Now that it is warm again I guess I need to take it to the Cadillac dealer. The temperature control still works in that it heats up the car when the outside temperature is colder than the inside. However, the "service air conditioner" light comes on, and it goes to "Econ Mode"and will not allow the ac to start.

Thanks for the information. I will go to a Caddilac expert.
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Thursday, April 24th, 2008 AT 5:13 PM
Tiny
BUZZSAW
  • MECHANIC
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You need to find out what code the AC is setting, thats why it goes to econ all caddies 89 and up do the same thing. Try going to autozone for the code im not real familer with 88's whats the motor size? 4.1 or 4.5 or 305 or 350 chevy?
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Friday, April 25th, 2008 AT 9:32 PM
Tiny
JRNEAVES
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The engine is 4.5.
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Saturday, April 26th, 2008 AT 8:00 AM
Tiny
BUZZSAW
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Is there a way for you to take a picture of your heater and AC controls. I need to see what it looks like
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Saturday, April 26th, 2008 AT 2:24 PM
Tiny
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Here is a picture of the Cadillac temp control panel. You can see the Service Airconditioning" light lit.


https://www.2carpros.com/forum/automotive_pictures/182288_caddy_1.jpg

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Sunday, April 27th, 2008 AT 8:21 AM
Tiny
JRNEAVES
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I had a brainstorm to disconnect the battery and re-connect it to see if that reset the A/C controls. IT DID! Now, what does that tell us?
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Sunday, April 27th, 2008 AT 11:35 AM
Tiny
BUZZSAW
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Try pushing off and warmer at the same time, with the key in the on position to see if it will go into diagnostics, it works with 89's and up to get codes
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Sunday, April 27th, 2008 AT 12:13 PM
Tiny
JRNEAVES
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I followed your instructions. Here are pictures of the result. Is this the diagnostic mode?


https://www.2carpros.com/forum/automotive_pictures/182288_caddy_01_3.jpg



https://www.2carpros.com/forum/automotive_pictures/182288_caddy_02_3.jpg

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Sunday, April 27th, 2008 AT 2:39 PM
Tiny
BUZZSAW
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It means the code went away, I need to see if that heater control head will put the car into diagnostics, push off and warmer at the same time, with the key in the on position, look at the message center there and see if you get codes from it, other wise take it to autozone and get the codes read when the light comes back on its free and maybe we can kick this in the butt, lol
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Monday, April 28th, 2008 AT 9:18 AM
Tiny
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Autozone said their instruments only go back to 1993 Cadillacs. More news, though.
The temperature outside today is around 40 degrees. The heater controls quit working again. I disconnected the battery but it did not reset. I will try again this afternoon because it is supposed to heat up to 80. Also, when I press the off and warmer buttons with the engine running it lit up the message center with the following, like it was running diagnostics. Messages in order they appeared..8.8.8, E52, F, F46, F47, F.F, F47, .7.0.

Are these diagnostic codes?
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Monday, April 28th, 2008 AT 10:49 AM
Tiny
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There you go thoes are your codes, yeah! Lol

the E52 is throttle angle prob, you need to clean out your throttle plates and egr tubes, remove the air cleaner engine off, look down the throttle plates and there are 2 tubes in the bottom, make sure there cleaned out use a coat hanger, then start it up and with a can of carb and choke cleaner clean out the black junk in the throttle plates

your f46 and f47 are you AC codes, when codes are present it wont work, F47 I know is low freon level F46 may be high pressure switch, I would get both of them changed (switches) High and low pressure switches as long as the freon is still full

did they change the orfice when they have done your evac and recharge, have them do that also, the low pressure switch you can change, but the high switch has to be evacuated

also if it is still R12 you may want to switch it over to R 134 freon the kit is cheap 30 - 35 bucks
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Monday, April 28th, 2008 AT 11:28 AM
Tiny
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Thanks for your help.
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Monday, April 28th, 2008 AT 12:19 PM
Tiny
BUZZSAW
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Oh yeah to erase the codes run the diagnostics and I think you use econ and cooler to erase try that and let me know
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Monday, April 28th, 2008 AT 3:40 PM
Tiny
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The Ecopn-cooler combo did not clear the codes.
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Monday, April 28th, 2008 AT 7:53 PM
Tiny
BUZZSAW
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Try after doing the diag thing the hi or low buttons do hi first see what that does push and hold it. It may just go into parameters of sensors thats not what you want or do econ hi buttons at the same time hold them in and econ lo it should just blink and erase the codes thats what were looking for
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Tuesday, April 29th, 2008 AT 12:10 PM

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