Troubleshooting Mirror Temp/Compass Install-Your Thoughts Welcome

[Rogue]

Hi all,

I recently received a rearview mirror with the compass and temperature feature. Yesterday I did the install, and it powers up and all just fine with one issue. I ran the power to the ignitition/12 V power supply for the radio, ground to a grounded screw in the cab, and the green wire for the reverse lights/autodim feature to ground (for now) as well. However, my temperature is acting all wacky, reading extreme at 88* or -32* F. The actual temperature is about 35-50* yesterday during the install from 4pm to 10pm. I'm stumped and would welcome your thoughts on what could be causing this.

Here's what I tested so far:

-Tested resistance in the sensor since I think it's basically a thermistor and that's how the mirror calculates the temperature, which has been ranging from 6.5 kohms to 8.5 kohms, which according to the attached chart isn't unreasonable. Going to do more testing on it today.
-Tested the resistance in the wiring from sensor to mirror, since I know folks have had problems with bad solder or crimp connections. The resistance in the wires was half an ohm, if not less, which I suspect is just due to the copper loss idea.
-Switched the wires for the temp sensor, with no change. This wouldn't matter anyway since polarity doesn't matter when measuring resistance.

The only other thing it could be would be the mirror itself, but the seller tested it before sending it to me and it appeared to be working correctly and I know he would not intentionally send me a bad mirror. So I'm at a loss for what is going on here.

I'm going to test the sensor some more this afternoon and post on here what happens. If anyone reading this can think of something I overlooked or other thoughts on this issue, please let me know!

Best regards,

Nathan

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[Rogue]

Well, it's definitely not the sensor. The sensor is reading 6.5 Kohms, and the actual temperature here is 48* F. The mirror is reading at 88* F. So I'm thinking it's a mirror issue. The temperature display changes as I blow hot air on it or hold the sensor in my hand. Anyone know how to reset the mirror or if that's even possible?

 

[twomanymontes]

I had a similar situation when I installed mine, but I tracked it down to a poor connection where I made the weather pack connector. Mine would read 75* when it was 20* outside.

Just because the seller says he tested it, doesn't mean it's right. He probably just plugged it in, checked and made sure it lights up. There is a way to recalibrate the compass, Not sure if it recalibrate the temp as the same time

 

[Cokeman95]

Well, it's definitely not the sensor. The sensor is reading 6.5 Kohms, and the actual temperature here is 48* F. The mirror is reading at 88* F. So I'm thinking it's a mirror issue. The temperature display changes as I blow hot air on it or hold the sensor in my hand. Anyone know how to reset the mirror or if that's even possible?

I had the same issue and it was the mirror itself. I couldn't find a way to reset it so just picked up another one at the junkyard and problem solved.

Sent from my SAMSUNG-SM-G900A using Tapatalk

 

[Rogue]

I had a similar situation when I installed mine, but I tracked it down to a poor connection where I made the weather pack connector. Mine would read 75* when it was 20* outside.

Just because the seller says he tested it, doesn't mean it's right. He probably just plugged it in, checked and made sure it lights up. There is a way to recalibrate the compass, Not sure if it recalibrate the temp as the same time

I may have to try hooking the mirror up to my 12 V power supply in the house and running a resistor with a known value across the leads and see what it comes up with. Might tell me 100% if it's the mirror or bad connection then.

 

[Rogue]

I had the same issue and it was the mirror itself. I couldn't find a way to reset it so just picked up another one at the junkyard and problem solved.

Sent from my SAMSUNG-SM-G900A using Tapatalk

I saw one on ebay for $20 shipped in decent shape, so I may just grab that and try it. Worst comes to worst, I have a spare mirror around if the other one is fine.

 

[Cokeman95]

Hope it solves your issue. I've got a dual display one and love it.

Sent from my SAMSUNG-SM-G900A using Tapatalk

 

[Rogue]

Still need to do some more testing on the mirror/setup this weekend if I get some time, but it's been consistently reading 40* over the actual temperature this week while driving.