Hood Ajar, Ambient Temperature not working

[jeep1]

So..... AUX battery was replaced less than a year ago, I only have 6K on it and I keep the truck on a battery tender.

Randomly the hood ajar warning has shown up and the ambient temperature stopped working. Check Engine light is on and its throwing B181E-13 "hood ajar input circuit open" and P0070-15 "ambient air temperature sensor circuit-circuit short to battery or open" Both of those are Body Controller codes. Also throwing P257F "engine hood switch high" which is a Powertrain Control error.

I've pulled the relevant plugs from the BCP and confirmed I've got continuity on the harness between the connector under the hood (XY103A) and the BCP C1 and C4 connectors.

Next up is to replace "Headlight Wiring Harness Right Mopar 68282740AC" but figured its worth asking here if anybody else has any ideas...

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[Mr._Bill]

Did you check for shorts between pins when doing the continuity tests? I would suspect harness damage, either heat or animal caused.

 

[Gladbrennan]

A continuity test would obviously troubleshoot a "short" when testing genius. Your spineless general statment that doesnt assist in helping makes me think you're either a robot or an idiot.

 

[Dougstdig]

A continuity test would obviously troubleshoot a "short" when testing genius. Your spineless general statment that doesnt assist in helping makes me think you're either a robot or an idiot.

Wow...someone's panties are in a twist... Before you get too critical of someone else, learn how to spell check and type. Better yet, if you don't have something to contribute, reconsider replying at all.

 

[Gladbrennan]

Wow...someone's panties are in a twist... Before you get too critical of someone else, learn how to spell check and type. Better yet, if you don't have something to contribute, reconsider replying at all.

What did you contribute with that response genius?

 

[Dougstdig]

What did you contribute with that response genius?

My point made. At least this time you learned how to spell check. Now stop posting just to cause trouble.

 

[b-roc]

So..... AUX battery was replaced less than a year ago, I only have 6K on it and I keep the truck on a battery tender.

Randomly the hood ajar warning has shown up and the ambient temperature stopped working. Check Engine light is on and its throwing B181E-13 "hood ajar input circuit open" and P0070-15 "ambient air temperature sensor circuit-circuit short to battery or open" Both of those are Body Controller codes. Also throwing P257F "engine hood switch high" which is a Powertrain Control error.

I've pulled the relevant plugs from the BCP and confirmed I've got continuity on the harness between the connector under the hood (XY103A) and the BCP C1 and C4 connectors.

Next up is to replace "Headlight Wiring Harness Right Mopar 68282740AC" but figured its worth asking here if anybody else has any ideas...

Another step in troubleshooting your hood ajar issue is to disconnect your hood switches (I checked early on and may be misremembering, but I think that when they are extended that they complete a circuit). Once disconnected, you can double check my aging memory with a continuity test. If I am correct about the switch, then disconnecting it should make it impossible to have a hood ajar error (unless you have a harness short or a bcm error).

With the ambient temp error plus the ajar message, I doubt that the switches are the problem, but it is an easy check (and an easy fix if it is the problem).

Good luck!

 

[sharpsicle]

I also would suspect a short somewhere. But before going that far, it's easier to verify the switches/sensors aren't the problem first. Tracing down shorts or breaks can be a pain, so rule out the simple things before going down that rabbit hole. You'd hate to go through wire tracing just to find out the problem was actually what the code said it was.

And before someone tries to stir the pot again, a continuity test along a wire would not show a short. It would show if there is a break in the line or not. Hence the word, continuity. If you aren't also considering shorts and testing specifically for them, you could easily do a continuity test and see no issues. For instance, you could take 3 wires, merge them all together halfway down the harness, then separate them again, and all 3 would show continuity since none are broken. Testing for shorts is similar in nature to a continuity test but has key differences in how it's executed.

 

[jeep1]

And before someone tries to stir the pot again, a continuity test along a wire would not show a short. It would show if there is a break in the line or not. If you aren't also considering shorts and testing specifically for them, you could easily do a continuity test and see no issues.

Good point .... going to be a pain in the ass to find the short if it exists. That harness ends up being in the full body harness that runs along the back of the firewall and down through the passenger footwell.

in theory, if I have a short, I should be able to find continuity either to ground or to one of the other wires in the bundle and considering I'm getting two specific codes, the first place to check will be across those specific wires.

 

[sharpsicle]

Good point .... going to be a pain in the ass to find the short if it exists. That harness ends up being in the full body harness that runs along the back of the firewall and down through the passenger footwell.

in theory, if I have a short, I should be able to find continuity either to ground or to one of the other wires in the bundle and considering I'm getting two specific codes, the first place to check will be across those specific wires.

And don't forget, shorts and breaks can be temporary in nature. The wires might only connect to each other or disconnect when they flex in the right way. So you'll also want to be wiggling the wire bundle in various spots to see if you get a result. Harley actually put this in their shop manual for their motorcycles, telling the tech to do a "wiggle test" to check for shorts and/or breaks in the harness.

 

[Dougstdig]

Good point .... going to be a pain in the ass to find the short if it exists. That harness ends up being in the full body harness that runs along the back of the firewall and down through the passenger footwell.

I want to believe there was a TSB or Recall on this. My memory is selective for some reason as to what it holds onto. Specifically with this harness that runs beneath the battery and down to the frame. It seems there was either a heat issue or some appendage that stuck out that chaffed the harness. Though I can't remember specifically who mentioned it here in the Forum, I want to remember that there have been several where the dealer took care of it. If this is the case and you're still under warranty, I definitely wouldn't go digging around in looms looking for it. Let them do it.

 

[jeep1]

I want to believe there was a TSB or Recall on this. My memory is selective for some reason as to what it holds onto. Specifically with this harness that runs beneath the battery and down to the frame. It seems there was either a heat issue or some appendage that stuck out that chaffed the harness. Though I can't remember specifically who mentioned it here in the Forum, I want to remember that there have been several where the dealer took care of it. If this is the case and you're still under warranty, I definitely wouldn't go digging around in looms looking for it. Let them do it.

Oh......time for some searching. Of course, I've already spliced into the harnesses to bypass the ambient temp sensor wires. But as painful as it is to do, actually pulling the fuse box and getting a good look at the loom wouldn't be hard.. just time consuming. Maybe its a good excuse to do a dual battery setup and delete that useless secondary battery

 

[b-roc]

A clarification on my earlier suggestion ... just in case it came off as stirring the pot (not my intention) ... I was intending that once you are disconnected from the switch that you should check for continuity of the switch with both the switch depressed and extended

As to the TSB, I have a vague recollection of it too ... I believe that it was specific to the diesel so I promptly let the details fade away since I have 3.6

As to the short, the easiest way to test for this (without specialized equipment) is if you have a multimeter with a diode check function that has an audible tone (use that mode) ... then simply connect one end of the multimeter to the pin of interest (easiest way is with a single female plug connected to the pin of interest) and then sweep all of the other pins with the other multimeter probe listening for the beep ... this is unlikely to catch a transient short though

 

[jeep1]

A clarification on my earlier suggestion ... just in case it came off as stirring the pot (not my intention) ... I was intending that once you are disconnected from the switch that you should check for continuity of the switch with both the switch depressed and extended

As to the TSB, I have a vague recollection of it too ... I believe that it was specific to the diesel so I promptly let the details fade away since I have 3.6

As to the short, the easiest way to test for this (without specialized equipment) is if you have a multimeter with a diode check function that has an audible tone (use that mode) ... then simply connect one end of the multimeter to the pin of interest (easiest way is with a single female plug connected to the pin of interest) and then sweep all of the other pins with the other multimeter probe listening for the beep ... this is unlikely to catch a transient short though

Oh you didn't come off as stirring the pot at all. And yes, that is what I've been doing with the multimeter. I hadn't considered a short so wasn't specifically looking for it. Will need to pull the plugs and start retesting.

Getting at the C1/A and C4/D connectors at BCP is a pain in the ass.. up under the dash, not enough room for two hands etc.. Definitely easier with the door off so you can get better angles at everything. C4 isn't awful but I pretty much have to pull all the plugs and then remove the BCP from the body before I can get at the little lock pin on C1. My back and hands aren't as young as they once were!

 

[sharpsicle]

Oh you didn't come off as stirring the pot at all. And yes, that is what I've been doing with the multimeter. I hadn't considered a short so wasn't specifically looking for it. Will need to pull the plugs and start retesting.

Getting at the C1/A and C4/D connectors at BCP is a pain in the ass.. up under the dash, not enough room for two hands etc.. Definitely easier with the door off so you can get better angles at everything. C4 isn't awful but I pretty much have to pull all the plugs and then remove the BCP from the body before I can get at the little lock pin on C1. My back and hands aren't as young as they once were!

I would honestly test from the switch connector side. It should give the same ability to test in terms of seeing a short. Plus, chances are very high that if something's gone wrong with the wiring, it's happened on the engine bay side anyway. I wouldn't imagine you need to go under the dash again unless you have absolutely no other options to test.

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