dual climate control

[fessywig]

Hi - I have a 98 Grand Prix GT with the 3.8L engine and most of the goodies, including a HUD, dual climate control, and read outs. The a/c works well when it gets going! The problem is sometime improper external temperature reading on the climate control. A little hard to explain. An example might be sufficient. Parked overnight and in the morning the ext temp reading is correct (if I believe the radio). The overnight temperature is, say 18 C. Start up the car and everything is rosy!; however, it is now mid afternoon and the ext temp is 30 C. The ext temp reading is still 18 C. and the climate control acts appropriately, i.e. provides some cooling. NOW..., to get the ext temp reading to correct itself and decide it is really 30 C. outside and provide appropriate cooling (which it does); as far as I can determine, the car has to travel as least 2 km without stopping! On a good run (2 km or more) I can amaze my friends by telling them to watch the ext temp readout and can predict, within 0.2 km (over 2 km) that the temp reading will increase to the actual outside temperature. If the car stops within the 2 km, the process must begin again - I can drive 25 km in the city hitting each stop light, and the ext temp reading remains the same. Please note, the ext read out reacts very nicely to a decrease in temperature, but not an increase. I don't know whether there is a connection between the climate control and initial speed, or the brakes or timed air flow, or the speedometer or all of them, or none of them, or some wire or switch must be 'heated up' over a certain continuous distance, or I just don't know'!!!. Is there something to clean, remove, beat, change, or swear at that might get me some relief while sweating in rush hour traffic?

Many thank yous', in eager and sweltering anticipation of an answer or direction. All donations gratefully received!!!

(I have asked the masters (2 GM dealers); the bemused look was but a precursor to the "I've never heard of that before" response)

[s_jo4]

i can't stand a dealership anymore, i run into nothing but a bunch of work behind a desk idiots that won't let you physically talk to a technician to tell them your situation and get a real reply back. 9 times out of 10 they won't fix the real problem or be able to pinpoint unless it's that obvious and their solution to everything is run it then replace it until they get it "working" like it should. taking a couple cars down to the shop to have recharged/fixed and i'll ask them about it, they're on top of all makes/models.

[Ripn12s]

Probably need a new ambiant air temp sensor.

Cost is like 7-12 dollars

Standing infront of car look on the left side inbetween the radiator and bumper. You should see the sensor there.

[fessywig]

Thank you. I went out and bought a new ambient temperature sensor and installed it. To make a long story short - all same! Went 25 miles before the ext temp readout moved up to when it was supposed to be, i.e. 24 miles of stop and start and the last 1.5 miles non stop.

So, any suggestions? The dual climate control is basically electronic, so is there some kind of 'reset' botton or eqivalent? Would anything happen if I unhooked the ground wire to the battery for, say, 20 minutes? Would the climate control's brain unsramble?

Awaiting your good advice

[Ripn12s]

When I installed a new sensor it took a few drive cycles to start reading correctly.

Is that little stick figure guy still flashing???

[fessywig]

The little stick guy has never flashed! The only problem with the A/C (and the control) is that the vehicle must travel at least 2 km continuously before the ext temp read out will display a warmer ext temp. When that condition has been fulfilled, the control appropriately adjusts the air flow and cooling air temperature. (Remember, if the outside air is cooler that the initial ext temp reading, the ext temp readout will record the lower temperature within seconds of starting the car).

Thank you

[Ripn12s]

If the ext. air temp is lower then 50, if I remember correctly, the a/c will not work. The little stick figure guy isnt flashing then I dont know what to tell you. When it does flash then that means there is a trouble code and something is wrong.

[fessywig]

Many Thanks!

So, .....you can appreciate how frustrating the glich is! Any place I can get an inexpensive wiring diagram to see what and where all the wires go and to what they are connected. I am determined to attempt to figure out why the car must go 2 km without stopping before the ext temp registers the correct (warmer) outside temperature. (short of buying a new climate control) What is it about slowing down, or putting on the brakes, or stopping within 2 km which indicates to the climate control centre that it must reset. How does the climate control know that the car has gone 2km continuously....or does it?

Any ideas? I'm all out!

[PoconoCharlie]

Originally Posted by Ripn12s

If the ext. air temp is lower then 50, if I remember correctly, the a/c will not work. The little stick figure guy isnt flashing then I dont know what to tell you. When it does flash then that means there is a trouble code and something is wrong.

Hello,

I am new to the forum, but found this thread using Google. I realize this a Grand Prix forum, but please indulge me:

I have a 94 Buick LeSebre. Recently, I've noticed troubles with the dual-climate control. The passengers side blows cold air while the drivers blows warm air (ext air temp in 30's, climate control set to 72). It is generally set in ECONO mode (where cold = unheated) but my tests with HEAT & AUTO produced no heat on the passenger side.

While my dash lacks a 'stick man', the temp numerals have been flashing this week. After a time, somewhere between 40-50 miles, the air coming out of the vents often stabilizes (but not always), and the numbers stop flashing.

I googled 'GM "ext temp" climate control temperature blinking' and got this thread. You mentioned the blinking icon indicated possible trouble code; can you provide me with links or other info so I can diagnose this problem?

Many thanks...

[Van2000GTP]

Fessywig,

I'm a little late in responding; but, it may help other readers...

What you're describing is how GM designed the sensor behavior - to prevent false readings from underhood temperatures. Here's an excerpt from the shop manual:

Ambient Outside Air Temperature Sensor Description

The outside air temperature sensor is located in the front grill area under the front bumper of the vehicle. The HVAC control head uses this sensor to receive information on ambient air temperature. With this information, the HVAC control head will give the driver the outside air temperature on the digital display. If the outside temperature increases, the displayed temperature will not change until:

• The vehicle's speed is above 32 km/h (20 mph) for approximately one and a half minutes.
• The vehicles speed is above 72 km/h (45 mph) for approximately one minute.

These delays help prevent false readings. If the displayed temperature goes down, the outside temperature display is updated immediately. If the vehicle has been turned off for more than three hours, the current outside temperature will be shown when the vehicle is started. If it has been turned off for less than three hours, the temperature will be recalled from the previous vehicle operation.

[BNaylor]

Originally Posted by Van2000GTP

Fessywig,

I'm a little late in responding; but, it may help other readers...

What you're describing is how GM designed the sensor behavior - to prevent false readings from underhood temperatures. Here's an excerpt from the shop manual:

Ambient Outside Air Temperature Sensor Description

The outside air temperature sensor is located in the front grill area under the front bumper of the vehicle. The HVAC control head uses this sensor to receive information on ambient air temperature. With this information, the HVAC control head will give the driver the outside air temperature on the digital display. If the outside temperature increases, the displayed temperature will not change until:

• The vehicle's speed is above 32 km/h (20 mph) for approximately one and a half minutes.
• The vehicles speed is above 72 km/h (45 mph) for approximately one minute.

These delays help prevent false readings. If the displayed temperature goes down, the outside temperature display is updated immediately. If the vehicle has been turned off for more than three hours, the current outside temperature will be shown when the vehicle is started. If it has been turned off for less than three hours, the temperature will be recalled from the previous vehicle operation.

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