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Old 12-20-2009, 06:25 PM   #1
Blue)(Fusion
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Outside Temperature Incorrect

Hi all,

Was curious if there's any particular reason that the OAT sensor would become somewhat sporadic. It seems to start off with a close to accurate indication, but after a couple minutes of driving, it will begin to climb to around 70-80F when the true outside temp is closer to 20-30F.

I already checked for debris around it and it was clean. I also thought maybe heat from the radiator was getting to it, but I don't see why it would be now. Especially since it was like this even at 70+MPH.

I didn't think of bothering to fix it until I drove home today and had to play with the EATC because it was switching between cold and warm air because it thought it was warmer outside. So now looks like I sure will be figuring out something.

Thanks.
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Old 12-21-2009, 01:27 PM   #2
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Re: Outside Temperature Incorrect

FWIW, I removed the sensors, cleaned the contacts and put some new dielectric grease on it and it still is way off. Starts off around ambient temp, then rising quickly to far above actual temp. This was before the coolant was even off the cold mark.
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2000 Mercury Grand Marquis LS
- 119k / 14.89s @ 92.11MPH [ pictures | videos ]
> Dual Flowmaster Delta 40s / J-Mod / PI Intake Manifold & Cams / Marauder Air Box & 80mm MAF / 3.55 Trac-Lok
> Bumper Tuck / Steeda UD Pulleys / CVPI Zip Tube / Ported & Polished Plenum / BBK 70mm TB
> BOC 93 Octane Tune / Headlight Relay Upgrade / 17mm rear stabilizer bar / Heinous Aluminum Billet Rear Control Arms
> CVPI aluminum driveshaft

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Old 12-23-2009, 12:13 PM   #3
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Re: Outside Temperature Incorrect

Just to let others know that experience this issue, I replaced the ambient air temperature sensor and solved the issue. The part was $17 at NAPA
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2000 Mercury Grand Marquis LS
- 119k / 14.89s @ 92.11MPH [ pictures | videos ]
> Dual Flowmaster Delta 40s / J-Mod / PI Intake Manifold & Cams / Marauder Air Box & 80mm MAF / 3.55 Trac-Lok
> Bumper Tuck / Steeda UD Pulleys / CVPI Zip Tube / Ported & Polished Plenum / BBK 70mm TB
> BOC 93 Octane Tune / Headlight Relay Upgrade / 17mm rear stabilizer bar / Heinous Aluminum Billet Rear Control Arms
> CVPI aluminum driveshaft

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Old 12-23-2009, 06:34 PM   #4
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Re: Outside Temperature Incorrect

OK. That is good to know even though I do not have one.
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Old 08-17-2010, 02:34 AM   #5
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Re: Outside Temperature Incorrect

I don't know if you ever solved your problem, and I know this problem is a little old, but I feel that another approach to your problem might be beneficial.

Try removing the automatic air temperature control unit and inspect the wire harness, and if you can get inside it, the soldering. I know my '92 is very different, but my erratic ambient air temperature was caused by a poor solder joint at the dash, not the sensor. Ford seemed to have trouble soldering, and I'm not the only one who had that trouble.
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Old 08-17-2010, 09:39 AM   #6
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Re: Outside Temperature Incorrect

I did solve it with a new sensor. It reads 2-3 degrees warmer than actual (compared to my IAT sensor which is correct) because it seems to be made from a different material, but it works and I know to take that into account.
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2000 Mercury Grand Marquis LS
- 119k / 14.89s @ 92.11MPH [ pictures | videos ]
> Dual Flowmaster Delta 40s / J-Mod / PI Intake Manifold & Cams / Marauder Air Box & 80mm MAF / 3.55 Trac-Lok
> Bumper Tuck / Steeda UD Pulleys / CVPI Zip Tube / Ported & Polished Plenum / BBK 70mm TB
> BOC 93 Octane Tune / Headlight Relay Upgrade / 17mm rear stabilizer bar / Heinous Aluminum Billet Rear Control Arms
> CVPI aluminum driveshaft

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