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I Have a 91 Deville, converted to R134, and the AC was working fine. Now, it suddenly acts like it is plugged or icing up. The pressures on high and low start out fine and it cools well for 5 minutes, then the compresser starts short-cycling and the low pressure drops and the high climbs into the 350 range. I have replaced the high side temperature switch, tested the low side switch, and tested the low pressure cutout switch. I have removed the lines and checked for blockages. The one thing I have been unable to check is the orfice tube- Does any one know where it may be located? I have called the Dealer, and they had several suggestions, but it was not there. Could it be built into the dryer? Any other ideas on what may be causing the problem?
Thanks!
 

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1994 deville
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find the coolant overflow jug on passenger side fender. move straight over toward the engine to the ac lines. the lines are run one over top of the other, on one of the lines, )NOT THE ONE COMING FROM THE ACCUMULATOR AT FIRE WALL) but the other one u will see a sensor, above this sensor is a fitting. break this fitting and inside the line running toward the front of the car is the orfice tube. pull it out. new one is .99 cents. now help me, i rebuilt my ac on a 91 deville, now it is giving a f12 code, says temp switch on lowside. where is this switch its talking about.
 

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'87 SDV
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The low temp sensor is on the smaller of the two A/C lines, back near the firewall. There should be a Pink/Black wire and Grey wire running to the connector.

First try clearing the codes and see if it returns. An intermittent code requires different diagnosis than a hard code.
 

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'87 Coupe DeVille 4.1L FWD(New engine '08) 1981 F100 '03FXDL
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879 Posts
The pipe coming from the accumulator into the evaporator has the orfice tube. Look for some little dimples in that line. Getting the thing out can sometimes be a pain. I converted my system to 134 in 1998. Back then I used a GM White-color tube. Last Summer I changed my accumulator and replaced the tube using a Blue-color Ford tube. I'm getting a better evaporator 'flood' with the Ford tube.
 

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1994 deville
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hey noahsdad, i reset this f12 code by turning on the egnitition and then holding down the off and warmer buttons, this gets into diagnostic mode. then i hold down the off and low button to clear f codes. then turn the igntion off and start car but the code comes back. it must have cleared once because the ac came on and ran but after i shut off the car and started it up again i AM RECIEVING THE F12 Code and it want clear by diagnostics and i assume that is what is holding out the clutch. read somewhere about pulling battery terminal for a few seconds, tried that but code is still coming back. some people say u can,t convert these cars with climate control but i have done it before and a dealer told me he did not know of any problem converting them even with climate control. i had a pcm (powertrain control module) and bcm go out on this 91 and i replaced them with ones from a 1992 deville. I will look around the firewall behind the accumulator (passengers side) for the ac temp switch.
 

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99 Seville STS, 08 STS4 N* 1SG F55
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It looks like you are clearing the code correctly and it is returning - so it is not an intermittent code. Therefore you'll have to adjust something to correct the problem.
 

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'87 SDV
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You can convert older Cadillacs to R134. My '87 was done three years ago and works fine. The climate control is nothing more than a fancy thermostat.

You've cleared the code correctly, and it sounds like it's setting a hard code. I'm at work now and not near my factory service manual. If no one jumps in here with the diagnostic on an F12 hard code, I'll get back with you tonight.
 

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Sorry rpurdy for hijacking your thread.

Ricklh, I'll reply later in your original thread in this forum.
 
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