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need help with an A/C code


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98 deville 114K, started blowing sorta not cold enough air and gradually over 2 weeks got warm, except at high speeds than it was cold enough, very warm at low speeds, mechanic said the compressor was bad. Son in law reminded us it was recharged when we bought it in Feb. and maybe there was air in the lines, so he vaccumed it? and recharged it adding oil charge and conditoner/stop leak, nope didn't work..but the lines were cold before the orfice tube and warm after..so he opened the lines and the orfice tube was FULL of tiny metal shavings from the compressor! so I got a new compressor, dryer and orfice tube, put all on drained the system and charged it ( adding oil to the compressor first) now no cold air at all , no codes at the time and air will not stay on switches to econo, inside outside temps are correct, blower is fine. ((Compressor will cycle when hotwired from under the hood.)) we cleared all codes and tried again, THAN the service ac light came on. this is the only code to show up B1314 - Evaporator Inlet Temp Sensor Open Circuit my son in law is a certified GM/Chrysler mechanic, but has not worked on many cadillacs and is at a total loss.. how do you figure out what to do next?

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Hopefully, the system was flushed to remove the shavings.

Have you checked the electrical connection to the evaporator temp sensor?

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Kevin,

I think paintedalleys problem is her/his son in law though a GM mechanic is not familiar with Cadillac and doesn't know where the Evap inlet temp sensor is. I have searched my '97 manual and am unable to find it (maybe they didn't use it on '97's).

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The low side temperature sensor is mounted on the large line from the accumulator to the evaporator. The High side temperature sensor is on the smaller A/C line above the blower motor.

Check the connections to make sure they are clean and tight. Clear the code in diagnostics and see if it returns.

The '96 shop manual shows both sensors under the B1314 code yet refers to one sensor. The sensor the manual refers to is likely the one above the blower motor.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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B1314

The evaporator inlet temperature sensor is a thermistor that controls the signal voltage to the heater and A/C programmer. The heater and A/C programmer supplies voltage on CKT 731. When the sensor is cold, the following conditions exist:

The resistance is high.

The heater and A/C programmer receives a high signal voltage at pin D15.

When the sensor warms, the following actions occur:

The resistance decreases.

The signal voltage is pulled low through CKT 407.

The signal voltage varies between 5 V (open circuit) and 0 V (short circuit).

Conditions for Running the DTC

Turn the ignition to the ON position.

Action Taken When the DTC Sets

The A/C compressor clutch is not allowed to engage.

The IPC displays SERVICE A/C SYSTEM -- A/C COMPRESSOR OFF.

A default temperature reading of 5°C (41°F) is implemented.

Notes On Intermittence

If an intermittent DTC B1314 is set, use a Scan Tool in order to select the following settings:

Data list

Open/shorts data

Observe the reading

Manipulate the wiring while observing the Scan Tool . If a failure is induced, the reading will jump. Inspect for the following conditions:

Faulty terminal contact

An obstructed or defective sensor

Test Description

Perform the Diagnostic System Check before continuing with the diagnosis of this DTC.

The Scan Tool displays the low side temperature. Jumping the harness connector determines if the wiring or the sensor is the cause.

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well ok, both sensors are plugged in good, I guess they make a vaccume sound when unplugged and plugged in? all fuses are good in all 3 locations. unplugged the battery for 60 sec and read the codes, still only code is ICM B1314 son in law says there is 2.5 lbs of r134a and compressor cycles when hotwired or bypassed under the hood, is there a process of reseting anything after the compressor is replaced? (sigh!)

vanessa

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If the sensor is unplugged and the harness terminals jumpered, does the compressor cycle and the system operate properly? If so, the sensor may be defective. Logan's post is the troubleshooting chart from the service manual.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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son in law says there is 2.5 lbs of r134a

My manual shows system capacity of 2.0 lbs. I don't know if an overfill of .05 lbs would cause a problem or not. Just another thought.

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son in law is going to evacuate to system and check the orfice tube again to be sure it was drained good, just a double check and refill with 2 lbs so we'll see what happens? still does not explain the sensor code, didn't have that before this mess and the compressor will run if bypassed under the hood, he checked the sensors also for current flow and those checked out, using some kind of meter.. should I try to find a new sensor plug? can you get those at a parts house?

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Kinda sounds like it might be a bad sensor. Changing it now, while the system is opened would preclude having to evac and recharge again later. Not sure where to get one. Dealer for sure.

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I called the Cadillac dealer here and spoke to the parts guy, he said the evaporator temp sensor is a pressure sensor and does not have any relevance on the compressor cycling on or off, and that he has sold 3 of those switches this week for 1997 Deville’s, HOWEVER he said the 1998 (mine) has a refrigerant temp sensor in the small line running by the evaporator case and it determines the coolant temp and cycles the compressor on and off, it's a $21.00 part , the other Deville’s who put on the new sensor still had the same problem he said and recommend I try the refrigerant temp sensor..any input?? :D

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