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hello all this is the 1st time posting on here. i'm not really sure if this is a problem but this is what's going on. when i'm on the highway with my windows down no ac on the temp gauge is at normal (12 o'clock position) when i turn on the ac the gauge moves up 1 notch (1 o'clock position) when i turn off the ac it goes back to normal (12 o'clock position) is there something wrong where. i will post a pic up thanks
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Nothing wrong - remember that the A/C condenser dumps a LOT of heat in front of the radiator.

In your car, with NO A/C function set, the fans are controlled by the ECT sensor (Engine Coolant Temperature) - they go to Slow at 224 and Fast at 236. The coolant goes down to 213 and fans turn OFF and the cycle starts over - BUT fans rarely, if ever, run at above 40 mph or so - airflow through the radiator at speed is enough.

With some A/C or DEFROST function set, fans run in Slow all the time, so most cars see a steady needle at or just above the midpoint.

This gauge picture is a bit different from yours, but the ticks and notes represent the same temperatures - anything at or below the first tick past midpoint is normal. (1 o'clock on your gauge is really about the second tick past midpoint.........)

BTW.............Welcome Aboard !!!!!.................:highfive:

Update your profile (see ^^^^ mine) with your car, model, year - it really helps....................
 

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1997 Cadillac STS (BOSE w/AUX In, Massage Seats, URPAS, "Z")
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You can bring up the coolant temperature as one of your DIC selections when pressing the "Info" button. Just search how to do that in the IPC overrides. I can't remember right now specifics but it was posted many many time on this forum.

Oh found it:

1) Press the OFF and PASS WARMER (referred to from here as WARMER) buttons simultaneously to enter diagnostic mode.

2) Let the system read any codes it has stored. You will ultimately be presented with "PCM?". You will answer with the fan speed control button. UP = yes and DOWN = no.

3) Press DOWN until you are presented with "IPC?". On mine, it's the very next prompt. When you get to the "IPC?" prompt, press UP to enter the IPC area (Instrument Panel Cluster).

4) Press DOWN until you are presented with "IPC OVERRIDE?". Press UP to enter the override area.

5) Scroll down (with the DOWN button) until you get to Option E. Wait a second or two, and the override value will appear to the right where the TRIP ODOMETER normally reads. Yours will probably read "43". That's what mine read when I first did this.

Below are the Option E values:

- Coolant Temp message (64)
- Battery Volts message (32)
- Engine RPM message (16)
- Avg Mph message (8)
- Mph message (4)
- Fuel Used message (2)
- Inst Mpg message (1)

The stock displays (for analog E/K displays) are Battery Volts, Avg Mph, Fuel Used, and Inst Mpg, for a total value of "43".

6) Use the WARMER button to increment the value of the override. In this case, we want to add Coolant Temp, so we're going to add "64" to "43", or "107". Press the WARMER button repeatedly to increment the value from "43" to "107".

If you make a mistake, you can decrement the value by pressing the COOLER button.

7) To permanently save the new value, hold the FRONT DEFROST and the A/C buttons simultaneously until the new override value flashes once.

8) You're done. Press OFF repeatedly to "back out" of the diagnostic system. You'll probably need to press OFF 5 or 6 times to get out of the deep "menu structure" you're in now.

Now, the coolant temp (in units specified) should be one "stop" along the revolving door we call the DIC. If you are in metric units, the coolant temp will read in *C. If you are in standard units, it'll read in *F.
Don't use it in your daily drive as a default selection, it will drive you insane :bonkers: (it varies by 20*-30* in a matter of minutes).
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Don't use it in your daily drive as a default selection, it will drive you insane :bonkers: (it varies by 20*-30* in a matter of minutes).
^^^^ That's EXACTLY why the later models don't have it: 95% of modern car drivers will go paranoid if a "gauge" ever moves a hair.

Imagine the dealer warranty problems if someone could watch their oil pressure go from 20 to 64 psi, up and down, at every traffic light - or if the temp gauge actually responded to 20 degree changes. (The center area of our temp gauges is highly damped - a needle width covers about 25 degrees.......)

Look in these threads - "OMG !!! My temperature gauge went up a needles' width !!! The sky is falling !!!!"
 
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2010 DTS
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For what it's worth, my gauge never moves, with or without A/C. Check your condenser and make sure it is not clogged with dead bugs. Wouldn't hurt to flush it with a garden hose and/or compressed air.
 

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Definitely clean the front radiator & condensor area, especially if you haven't done. You will be surprised how much dust & bugs fly out of it.

I've done it few months ago and had to keep shooting air for over 30 minutes to finally not see anything flying out.
 

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2006 XJ, 2000 Eldorado ESC--total loss :(
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I wouldn't be too worried about it, as everyone prior already said. But it can't hurt to check that your fans do run with the a/c on.

Though the fact that it does it on the highway is strange... the PCM will not normally run the fans over some set road speed (say 35 mph) because the ram air is high and the fans are not needed. Does your car have all the lower air baffles in place? There should be a plastic shield between the engine subframe and the core support, and a flexible rubber shield between the core support and the bumper edge.

If all that checks out, you may just have one of odd gauges that responds to a slight increase in temp. Most never move, but some people have reported them up and down as load/speed changes.
 
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