Question-Ron,
-----I did go through the test and it did blink and then went back to 75 degrees and then off.Turned on the automatic temperature control to check to see if compressor is coming on,clutch engaged on compressor and then it seemed to shut off.So what do you think? Thanks for all the help you have given me.Thanks, Larry
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Followup To
Question -
A code did not come up after we did the procedure you told us about.Any ideas! Thanks, Larry-------------------------
Followup To
Question -
Cools sometimes & heats sometimes.Went to dealer with this problem and they said we need to replace ambient air temperature sensor.To do this you need to take out coolant and put sensor in and recharge.Another dealer said this would not fix the problem he was thinking this was the controls. We have the automatic temperature control type unit. Please help us! Thanks,
Larry
Answer -
Hi Larry,
On the ATC console there is a self-diagnostic capability that you can get to give you a code number as to what is wrong. Just set the unit for 75F, idle the engine, and then simultaneously press the floor, mix and defrost buttons (which are the first, second and fourth on the top row) and hold them until the display blinks, then release the buttons. The control display will then show a two-digit number if it has caught a problem. Then press the Panel button (first button on the second row) to see if any more codes come out. When the panel button push results in the display returning to 75 all the codes have been displayed. Either write back with the codes number or go to www. allpar.com/fix/codes_climate.html for a list of code translations. If the ambient temp is one of the codes, then there is a test for air flow that I can describe to you.
I don't believe that the dealer is correct about discharging the sytem in order to service the ambient sensor.
Roland
Answer -
Hi Larry,
Just out of curiosity, did the display blink and then just show no code number, or didn't blink at all? If the former then at least we would know that the unit doesn't think there is anything wrong with the ATC control part of the system, which would be helpful. I would say if that were the case, then you should begin with treating the situation like a standard AC unit: check to see if the level of refrigerant in the system is marginal which would cause a cooling type of inconsistency that you originally described. On the other hand, if display didn't blink then we haven't done the readout yet and we need to try and get that done. The procedure I reported to you was for cars up to 97, and I assumed it would work the same in your 99. So let me know what you saw on the display, please, and if it appears to you that the display was if fact telling you it found no codes, then I would go to an AC shop and have them check the pressure and recharge it if necessary. Another clue when it doesn't work is that the compressor will not be activated because there is a cut off that prevents the compressor clutch from engaging when the pressure is too low.
Roland
AnswerHi Larry,
I would begin then to investigate whether you have sufficient refrigerant in the system. There may be a visual check you can do. In one of the two refrigerant lines that are attached to the compressor you will find a round metal canister with a rectangular piece attached to its top. Some models have a sight glass built-in to the top of that piece. Run the engine, turn on the A/C, turn on the blower to high, set the temp to 68 or so, (and of course the ambient temp needs to be higher than that so the compressor comes on), then after a minute or so (and assuming that you are getting some cooling and the clutch is still engaged) look at the fluid showing in the sight glass. If is has bubbles then that means the refrigerant levels is too low and needs to be filled. If the clutch doesn't engage, if the temperature of the two lines attached to the compressor aren't quite different from oneanother, etc. then you are out of refrigerant. An AC shop can test the pressure and give you a measurement of the pressure in the system and advise more accurately, but that is a quick test you can do yourself. I wouldn't worry about the ATC unit at all until you verify that there is enough refrigerant in the system to produce cooling.
Roland
