1999 Cadillac Deville Low refregirant Indication

Tiny
SANSHAWKINS
  • MEMBER
  • 1999 CADILLAC DEVILLE
  • V8
  • 2WD
  • AUTOMATIC
  • 95,000 MILES
At first I had a continuous Low Refrigerant indication come on. I took it in for repair. They replaced the compressor. After it was fixed each time I drove for 15-20 minutes and the Low refrig would show again. I returned it 6 times to the repair and they do not know.
Note: Each time I pull the power to the battery and reconnect I get cool air for a while then the low refrig indication come back on. When It does blow it's real cool then goes off and showes the indication of low refig! They replaced both AC sencor and no change. Is this possibly a bad connection to the computer. If so where is the computer phycically located on this car so I can check the connections? What are your thoughts. Thanks, Sans
Do you
have the same problem?
Yes
No
Wednesday, July 14th, 2010 AT 4:41 PM

3 Replies

Tiny
FACTORYJACK
  • EXPERT
It is either a low condition, or a faulty sensor that is indicating a low condition. The best check would be the system pressures. If the low side pressure drops rapidly when the compressor cycles on, it is low, or possibly restricted.
Was this
answer
helpful?
Yes
No
+1
Wednesday, July 14th, 2010 AT 10:10 PM
Tiny
SANSHAWKINS
  • MEMBER
The low refrig still comes on even after both sencors were replaced and the preasures are at correct levels. It's start blowing cool air just after I reset the system by disconnecting the battery for a sec. It only runs for a 15-20 min time limit then goes back to LOW REFRIG again.
I'm thinking bad sencor wiring to computer or connections to computer. Is the computer very accessable from underneath the passenger side. I wanted to clean the connectors to the computer. Your Thoughts?
Thanks, Sans
Was this
answer
helpful?
Yes
No
+2
Friday, July 16th, 2010 AT 8:12 AM
Tiny
FACTORYJACK
  • EXPERT
The low pressure sensor is what will indicate a low condition, or a fault in that circuit. Here is the schematic and info for a 1349 code, 1348 is similar.

DTC B1347 Very Low A/C Refrigerant Warning


http://www.2carpros.com/forum/automotive_pictures/309872_315453_1.jpg



Circuit Description
In the process of controlling the compressor clutch, the heater and A/C programmer monitors certain inputs for an indication of a low refrigerant charge. If the system refrigerant state of charge falls below approximately 1/4 capacity, the heater and A/C programmer is capable of detecting this condition. The programmer will display VERY LOW REFRIGERANT--A/C COMPRESSOR OFF on the driver information center (DIC) in order to warn the operator.

The heater and A/C programmer determines the state of the charge by monitoring the temperature change in the low temperature sensor during the compressor engagement. This temperature drop is referenced by the heater and A/C programmer as a function of the ambient air temperature. If the refrigerant charge is too low, the refrigerant boils instantaneously after passing through the orifice tube. This action creates a large rapid change in the low temperature sensor reading. After several incidents are counted, the heater and A/C programmer sets DTC B1347. The message VERY LOW REFRIGERANT--A/C COMPRESSOR OFF will be displayed on the DIC. If a DTC B1347 is set, the compressor clutch disengages and remains disengaged until DTC B1347 is cleared. DTC B1347 may repeat if excessive pressure exists in the A/C charging station tank. Repair the A/C charging station before properly diagnosing DTC B1347.

Failure Conditions
The low side refrigerant temperature drops too quickly during several of the compressor cycles.

Action Taken When the DTC Sets
" The system disables the A/C compressor until the DTC is cleared.

" The system displays the VERY LOW REFRIGERANT--A/C COMPRESSOR OFF message on the DIC.

Check for 12 volts at the pink wire pin A, check for 12 volts out of the sensor at pin B, and at the terminal at the programmer. If you lose 12 volts on the programmer side, you are losing it to open switch or pressure below 10 psi. The programmer is under the RH side of the instrument panel.
Was this
answer
helpful?
Yes
No
+4
Friday, July 16th, 2010 AT 4:40 PM

Please login or register to post a reply.

Recommended Guides