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Ambient Temperature Sensor

MJP

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I am planning to swap out the temperature sensor located in the drivers side mirror to see if it helps correct the temperature inaccuracy issues. A friend printed out instructions from the PRODEMAND website and it says to first disconnect the negative battery cable. Can anyone who may have done the swap explain why it’s necessary to disconnect the negative terminal? If I do the swap without disconnecting the negative what would happen? It seems that a quick swap with the truck off shouldn’t affect anything but obviously I’m missing something.

Thanks in advance for your help.
 

kdoublep

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What do you mean swap? For a new OEM one or aftermarket? I've read it's the location of the sensor that makes it inaccurate.
 

Barnyard

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It's always good practice to disconnect the battery any time you're replacing electrical components on a vehicle. You might not have a problem, but is it worth the risk to save 30 seconds?

Sent from my SM-G996U using Tapatalk
 

djevox

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I am planning to swap out the temperature sensor located in the drivers side mirror to see if it helps correct the temperature inaccuracy issues. A friend printed out instructions from the PRODEMAND website and it says to first disconnect the negative battery cable. Can anyone who may have done the swap explain why it’s necessary to disconnect the negative terminal? If I do the swap without disconnecting the negative what would happen? It seems that a quick swap with the truck off shouldn’t affect anything but obviously I’m missing something.

Thanks in advance for your help.
In one acronym- CYA. Automotive manuals have been saying this kind of stuff for decades. It is not bad practice to do it, and prevents the chance of shorting something and frying the body module.
 

bigdodge

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they say to disconnect negative battery cable because that is safer then disconnecting the positive.
If you disconnect the positive and something lands on the battery you will have a short.

here is a better explanation
"The short version is that every vehicle made since the 1950s has the negative post of the battery connected to the metal frame and body of the car. If in the process of unbolting the negative battery cable you happen to get the wrench from the battery post to the body nothing happens. If you start with the positive post and happen to do the same thing you will get a big spark. Besides the damage that arc can do to things, it is also possible to ignite any hydrogen gas in the battery. This causes the battery to self-disassemble violently. Flying battery case parts, lead and sulfuric acid would tend to give your face rather strange and likely unattractive marks. Your eyes might not work very well afterwards either."
 

djevox

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they say to disconnect negative battery cable because that is safer then disconnecting the positive.
If you disconnect the positive and something lands on the battery you will have a short.

here is a better explanation
"The short version is that every vehicle made since the 1950s has the negative post of the battery connected to the metal frame and body of the car. If in the process of unbolting the negative battery cable you happen to get the wrench from the battery post to the body nothing happens. If you start with the positive post and happen to do the same thing you will get a big spark. Besides the damage that arc can do to things, it is also possible to ignite any hydrogen gas in the battery. This causes the battery to self-disassemble violently. Flying battery case parts, lead and sulfuric acid would tend to give your face rather strange and likely unattractive marks. Your eyes might not work very well afterwards either."
Yep, I’ve definitely done that a number of times, as well as getting too aggressive with loosening a terminal and shorting a wrench across the positive and negative terminals. Now that’s some big sparks.
 

HSKR R/T

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they say to disconnect negative battery cable because that is safer then disconnecting the positive.
If you disconnect the positive and something lands on the battery you will have a short.

here is a better explanation
"The short version is that every vehicle made since the 1950s has the negative post of the battery connected to the metal frame and body of the car. If in the process of unbolting the negative battery cable you happen to get the wrench from the battery post to the body nothing happens. If you start with the positive post and happen to do the same thing you will get a big spark. Besides the damage that arc can do to things, it is also possible to ignite any hydrogen gas in the battery. This causes the battery to self-disassemble violently. Flying battery case parts, lead and sulfuric acid would tend to give your face rather strange and likely unattractive marks. Your eyes might not work very well afterwards either."
That is not the reason for disconnecting negative terminal. That is a reason to not unhook just the positive, but not the reason the first step in most vehicle maintenance calls to disconnect battery negative cable.
 

MJP

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That is not the reason for disconnecting negative terminal. That is a reason to not unhook just the positive, but not the reason the first step in most vehicle maintenance calls to disconnect battery negative cable.
I apologize but I’m still confused. So does it even matter if I don’t disconnect the negative and leave the battery alone?
 

RebelWraith

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are you a mechanic?

I am
.....and? We are talking about electronics. Not a specialty area for most mechanics. The Ram 1500 has been switched over to AGM batteries, so your point about hydrogen gas is moot. Also, British imported vehicles like the Jaguar and MGB still used a positive ground well in to the 60s.

Any part on a vehicle that is not polarity sensitive doesn't care how electricity gets from point A to point B. The only reason positive grounding disappeared was because of standardization of transistors and diodes with a negative ground.
 

RebelWraith

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I NEVER GAVE INCORRECT INFORMATION

THE BATTERY CAN STILL SHORT OUT AND CAUSE ISSUES

YOU, YES YOU are nitpicking on the filled vis AGM

the fact is it is still dangerous to disconnect the positive FIRST



but keep stroking your ego.



you must not have anything else to do.
LOL, I never mentioned anything about the positive comment being wrong. You were inaccurate about the 50s comment and the battery type which I outlined already.

You are the only one who brought up removing the positive terminal. All the posts have been about removing the negative when working on vehicle electronics.

Stroking my ego. LOL....coming from the guy who used "are you a mechanic? I am" as a rebuttal instead of facts.
 
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