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Discussion Starter · #1 ·
My ambient temperature reading is very off. It's been reading about 30+- degrees over the actual temperature. I replaced the sensor and reinstalled it in the stock location but still reads high.

It's about 95 here today and I am parked the shade with a reading of 128 after driving 20 miles.

Any suggestions on other things to check out?

 

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It’s heat soaking because of where it is mounted. Also, the signal is not buffered like the newer vehicles. You can re-mount the sensor back in and out of the way of sunlight and cooling stack heat by putting it behind the left front turn signal/running light housing.
 

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Discussion Starter · #3 ·
I'll give that a shot
 

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Discussion Starter · #5 ·
It's super easy to get to if you pull the passenger headlight. Pulled it out of the stock mounting location and rerouted it up behind the headlight and into the fender area.

I will keep an eye on it next time I drive it.
 

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Discussion Starter · #6 ·
New sensor and relocated it to the fenderwell and it is still reading 25-30 degrees too high. I am going to let it ride since it is just a "bell and whistle feature" and not vital to my truck's functionality.
 

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Yeah, not all that sure about moving the sensor. I've been driving the same 2002 for 18.5 years now. It runs 95-96F every day here during the summer. My mirror has always been dead on and still is to this day. Sensor has never been touched or moved or anything else.

Only way it will show off temps is if you park it out in the sun for hours on a hot day and then it might show 105-110 or so but when you crank up the A/C and get the truck moving the reading comes back down to reality.
 

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New sensor and relocated it to the fenderwell and it is still reading 25-30 degrees too high. I am going to let it ride since it is just a "bell and whistle feature" and not vital to my truck's functionality.
What are you using for reference? Have you placed a thermometer, or used a temp gun to check the temp near the sensor? They are an instant read sensor in those years so they are really sensitive.
 

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Discussion Starter · #9 ·
I definitely agree that it is heat soak related. Temperature on the mirror matches the thermal heat gun after sitting overnight.

Gonna to let it idle for a bit and check it again.
 

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Along the same lines....Sort of> Not sure where on DF although somewhere im sure. My temp/ compass is faded sometimes. Where/How do i repair this?
 

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Discussion Starter · #11 ·
Drove @30 miles and the temp difference was 32 degrees when I arrived.

I don't know what the hell is going on....

 

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Discussion Starter · #12 ·
Along the same lines....Sort of> Not sure where on DF although somewhere im sure. My temp/ compass is faded sometimes. Where/How do i repair this?
Are your lights on when it dims?

Could try a new mirror.
 

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Are your lights on when it dims?

Could try a new mirror.
No! It is hard to read during the day sometimes/ most of the time when it is sunny out. Just like i still need to solder my gear indicator i can never see anymore. Im just not sure why the mirror is doing it.
 

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Drove @30 miles and the temp difference was 32 degrees when I arrived.

I don't know what the hell is going on....

A. I never use a weather app for temp comparison with an automotive ambient temp sensor. Been burned by that before.

B. You’re still heat soaking. Moving it may help some but the sensor is instant read. There is a reason why GM now severely buffers the ambient temp sensor on all of their vehicles. These older vehicles didn’t have that and customers were concerned with it just like you are.
 

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Discussion Starter · #15 · (Edited)
Follow up to the thread.

I pulled the grill and radiator cover to look for refrigerant leaks and to clean the cooling stack.

Well looky there!
What I thought was the ambient air sensor that I previously moved and that did nothing must be something else because I found another sensor that was laying right up against the stack.

Moved and zip tied it off to the side behind the bumper. Now the temperature reads as it should.

Are there 2 ambient air sensors on a LBZ?

First sensor I moved on the passenger side





Second one on the driver's side

 

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John Kennedy has a good tech tip on relocating the sensor. You pretty much found this out on your own but the information is good for others to follow.
 
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The winter grill cover really messes with this sensor too. I'm thinking about moving mine over.
 

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These older ambient temp sensors with their razor sharp readings are why the newer trucks have so much buffering into that sensor reading. Getting that sensor away from engine heat will certainly help it to read more accurately but I’ve just never put that much necessity into knowing the temperature outside the truck while I’m driving it, I guess. Furthermore, the reading is only really skewed with the truck is stationary for too long and there is engine compartment heat that is higher than the actual ambient temperature.
 

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There are two temp sensors, yes. I believe one is for the auto HVAC system? Not 100% sure. The other is for the temp reading on the mirror. Looks like you have found them both.
 

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The only time it really bothers me is when it kicks into high idle with the winter grill cover on. The winter grill traps the heat so the ECM kicks off the high idle because it thinks it's warmer outside than it is. That's the only reason I plan on relocating the sensor.
 
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