Electronic climate control

Have a question about the climate control sensor. How hard is it to replace?

Had to replace the hose set on my 96 rmw, rubbed a hole in it. Also replaced the orifice tube. Got it charged after evacuating it, but the wife was always complaining how it never got cold. So tonight got my digital temperature meter and measured the outlet temp. Around low 50's as I went to pick up my daughter from work. On the way home, hovering around the upper 50's. had the temp set at 68 F. So on a hunch set it to 60, as low as it would go, and low and behold, it fell to 48 degrees.

So I am assuming I need to Change the temp sensor? Don't really want to have to run the temp up to get it to heat this winter, or keep it down to 60 for cooling!

Am I on the right track and how difficult is it going to be to replace?

Thanks

Don in Mo

Could be the blend door actuator needs to be resynchronized. Disconnect the battery for a minute, then reconnect and turn the key to the run position. If it's quiet enough you should hear the door moving for about 3 seconds as it calibrates. During this time don't touch the climate control. Once the blower motor comes on it's done. Try it out and see if that helps.

Once the blower comes on, run the temp up to maximum, and then down to minimum. Also a system setup.

Thanks guys! Did both and sent the wife on her way.

Says its working fine so far:) 

Will see what she says on the return trip.

Don

According to the wife, the advice above worked! Said she had to turn the temp up cause it got too cold!

Thank you!

Don

my AC blows cold until about 25mph but then it gets hot. it also say auto econ & the Fahrenheit "F" keep blinking. im not sure what made it start doing that but i cant figure out how to get it back to normal... any ideas.

udownwitk wrote:

my AC blows cold until about 25mph but then it gets hot. it also say auto econ & the Fahrenheit "F" keep blinking. im not sure what made it start doing that but i cant figure out how to get it back to normal... any ideas.

It is probably low on refrigerant. Mine did a similar thing when it was low. Check the refrigerant level, fill if necessary, and then try disconnecting the battery for a minute, then reconnect. Follow the above instructions.

Fred Kiehl wrote:

udownwitk wrote:

my AC blows cold until about 25mph but then it gets hot. it also say auto econ & the Fahrenheit "F" keep blinking. im not sure what made it start doing that but i cant figure out how to get it back to normal... any ideas.

It is probably low on refrigerant. Mine did a similar thing when it was low. Check the refrigerant level, fill if necessary, and then try disconnecting the battery for a minute, then reconnect. Follow the above instructions.

thanks for the info fred!!! but sadly, i went outside to charge it up and it looks like im still on R12... so i cant do anything with it... have to look into my options...

udownwitk wrote:

thanks for the info fred!!! but sadly, i went outside to charge it up and it looks like im still on R12... so i cant do anything with it... have to look into my options...

This brings to mind a question:  the PO sad he thought my 93 was converted to 134a, but the fittings look like R12. If I hook pressure gauges to the system should I be able to confirm one or the other?

Thanks,
-Leland

Pretty easy actually,R12 systems use screw on fittings while R134 systems use click on hose fittings for recharging.

Yup, what Jim said.  Also, you CAN still get refrigerant for R12 systems.  Search ebay or similar sites for a product called Freeze12.  It's a direct replacement and works GREAT.  Sadly it's no longer being made but I regularly see it on such sites for sale though it's starting to get expensive.

EDIT: A quick epay search found multiple hits. Here's one for reference. I have this in my Red Cruiser and keep a couple cans around.
http://www.ebay.com/itm/FREEZE-12-R-12-R12-REPLACEMENT-NON-FLAMMABLE-NO-CFCS-12-oz-Can-/271451717063?pt=Motors_Car_Truck_Parts_Accessories&hash=item3f33c87dc7&vxp=mtr

udownwitk wrote:

my AC blows cold until about 25mph but then it gets hot. it also say auto econ & the Fahrenheit "F" keep blinking. im not sure what made it start doing that but i cant figure out how to get it back to normal... any ideas.

It's a good idea to mention the year of your car when you ask these kinds of questions, but from the description and picture, I assume it's a 91-93?

The flashing F/C indicates the system has detected a fault. You need to enter the HVAC diagnostic mode to extract the fault code. Press and hold the "TEMP ^" button while pressing the "Off" button simultaneously until the display changes to diagnostic mode. The display will then show any fault codes present:

00 - no faults
01 - Temp air valve motor potentiometer circuit open
02 - TAVM potentiometer circuit shorted
03 - Outside temp sensor circuit open
04 - OTS circuit shorted
05 - Inside temp sensor circuit open
06 - ITS circuit shorted
07 - Sun load sensor circuit open
08 - SLS circuit shorted
09 - Low refrigerant pressure
10 - UART failure

You can also monitor certain other functions in diagnostic mode. Press the "FAN ^" and "FAN ˅" buttons to switch the desired parameter, as indicated by the codes below. Then press the "F/C" button to display the value of that parameter:

02 - Inside Air Temp sensor
03 - Outside Air Temp sensor
04 - Sun load sensor (above 200 = dark; 150 or below = bright sun)
05 - Engine temperature (°C)
06 - Vehicle speed (MPH)
11 - Temp Air Valve Command (0 = full cold, 255 = full hot)
12 - Temp Air Valve Feedback (should be within 3 points of commanded position)
13 - Temp Air Valve Full Hot calibrated value (should be >180)
14 - Temp Air Valve Full Cold calibrated value (should be <50)
18 - Number of Consecutive Short Compressor Cycles (indicates low freon if 10 short cycles are detected. Will disable compressor until reset)

To clear the diagnostic codes you can disconnect the battery like Fred suggests, or simply press "OFF" while in diagnostic mode.

So if Fred is right, you should have a fault code 09 and a short compressor parameter value of 10.

udownwitk wrote:

i went outside to charge it up and it looks like im still on R12... so i cant do anything with it... have to look into my options...

I wrote a long thread that includes a discussion of your options on the "other board". I won't reproduce it here due to length, but here's a link:

http://buickforums.com/forums/threads/26737-Basic-principles-of-Auto-AC

buickwagon wrote:

udownwitk wrote:

i went outside to charge it up and it looks like im still on R12... so i cant do anything with it... have to look into my options...

I wrote a long thread that includes a discussion of your options on the "other board". I won't reproduce it here due to length, but here's a link:

http://buickforums.com/forums/threads/26737-Basic-principles-of-Auto-AC

Long is a understatement but I am learning a lot,thanks Dwayne!

Flasheroo wrote:

Long is a understatement

You can't say I didn't warn you...   

It is broken down into a series of posts, each dealing with a different specific topic, so you can skip through the stuff you have no interest in.

Does the blend door actuator resynchronization apply to 94-96 RMSW with automatic climate control or just to other HVAC systems. My '95 RMSW starts out cold but after an hour or two I have to turn up the blower motor to get cold air our even though I can hear the blower blowing hard but against something under the dash. After another hour it starts blowing through the vents again. I'm not impressed with this system would rather have more control over the heat and cold, but like the outside temp readout.


Chris

It is the same system as all of the Automatic Climate control systems. Try disconnecting the battery, and let it reboot.

So the volume of air coming out of the vents gradually reduces? If you push the "Vent" button, does the volume of air return to normal (for the fan speed) within a few minutes?

If so, your evaporator is quite likely frosting over. The AC is actually slightly too cold, so moisture condensed out of the air then freezes to the evaporator coils instead of running down and out the drain elbow in the firewall. The build-up of frost blocks the air flow through the evaporator so not much comes out of the vents.

Pushing the "Vent" button disables the AC compressor, so the warm air blown against the evaporator by the fan quickly thaws the frost so air can again flow through the evaporator.

There's two possible causes. First, the system may be slightly undercharged. In this case, the pressure (and therefore the temperature) in the evaporator may be lower than at the compressor cycling switch. Check to see if the two evaporator lines are about the same temperature at the firewall. If the line from the evaporator to the accumulator is warmer than the line from the condenser to the evaporator, then the system is undercharged.

If the system is properly charged then most likely the compressor cycling switch is out of adjustment. There is an adjustment screw hidden inside the wiring connector. You have to unplug the connector to access it. Tiny tiny adjustments make a big difference in operating pressure range and you should have a known accurate low pressure gauge attached to the system to set the pressure above the freezing point.

I needed this post sunday,on the return trip from WF. At least now I know that the blinking light indicates a problem with the system. Thanks

Buickwagon,

This would explain the large puddle under the car several minutes after turning it off in this hot weather. I added a bottle (12? oz.) a month ago but it didn't help much, maybe needs a little more. Will check this weekend.


Thanks


Chris

Skier wrote:

This would explain the large puddle under the car several minutes after turning it off in this hot weather.  I added a bottle (12? oz.) a month ago but it didn't help much, maybe needs a little more.  Will check this weekend.

Don't add more unless it needs it. If the two lines out of the firewall are about the same temperature and the accumulator is wet with condensation (or covered in frost) then you are probably fully charged. Adding more will reduce the system's efficiency and risk damaging the compressor.

Water under the car after running the AC is normal. The water condensing out of the air has to go somewhere. Make sure you have the elbow on the condensate drain at the firewall. Without the elbow, air flow can prevent the water from draining out. Eventually it finds a way out inside the car and you get a wet passenger side carpet.

If the refrigerant charge is OK, but you have symptoms of icing (ie: slowly reducing airflow cured by pressing "Vent") then look to the compressor cycling switch (on the side of the accumulator) setting, as described above. If it lets the pressure (=temperature) drop too far then the evaporator may start icing up.

Buickwagon and Others,

1) Which way is the compressor cycling switch adjusted to reduce icing, clockwise or counterclockwise?

2) When resynchronizing the door actuator should the HVAC be set on auto or vent?

3) Lately my AC has switched from Middle to Floor and Defrost without any known reason is this due to vacuum leak or something else?

Thanks,


Chris


'95 BRMW

Clockwise will raise the cut-out pressure (ie: raise the minimum temperature) to reduce icing. 23PSI is about the lowest you want for R-134A.

I don't think it matters. I think either Auto or Vent will work. The difference between Auto and Vent is that Vent prevents the compressor from running.

Random changes in diverter door postition is often related to vacuum. However, the vacuum is controlled by electronics. Truly random changes are likely electronic. Changes associated with throttle position (eg: hard acceleration) are more likely to be vacuum.