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Weird A/C electrical problem

Discussion in 'Cherokee' started by kymartin6, Jun 18, 2017.

  1. Jun 18, 2017 at 12:58 PM
    #1
    kymartin6

    kymartin6 [OP] Member

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    First of all I am new to this site, and also just recently bought a 2004 Jeep Grand Cherokee with the 4.0 engine. we love the vehicle so far but something strange is happening. If you have the A/C on and turn on the headlights, it goes to full heater immediately. Turn off the headlights and the A/C comes back on. Any insight into this problem would be most appreciated.
     
  2. Jun 18, 2017 at 7:47 PM
    #2
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine Moderator

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    Welcome! Ive never heard of that, so hopefully someone can post in and help.
     
  3. Jun 19, 2017 at 5:56 PM
    #3
    kymartin6

    kymartin6 [OP] Member

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    Thanks Chris. It's a weird deal. I found one other guy that posted the same exact problem on justanswer.com jeep....... it was from 7 years ago. The guy answering the question thought it was an internal problem in the HVAC control head. The questioner never posted back to say if that was the problem or not. This may turn out to be a daytime driver in the summer months...... LOL......
     
  4. Jun 19, 2017 at 7:36 PM
    #4
    JKBob 25

    JKBob 25 Well-Known Member

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    Sounds like it's possessed. Lol. Sorry, the devil made me do it. ;)

    Hope some one here can help you.
     
  5. Jun 20, 2017 at 3:06 PM
    #5
    kymartin6

    kymartin6 [OP] Member

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    I hadn't thought of contacting an exorcist....... :cheers:
     
  6. Jul 11, 2017 at 5:16 PM
    #6
    kymartin6

    kymartin6 [OP] Member

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    Well......... I haven't solved the problem yet but..... I have a few more clues. I purchased a complete set of Jeep service manuals on ebay. The same ones a dealer would use. I looked at the schematics and saw that the Body Control Module.... (mounted to back of the fuse panel)..... does a lot of stuff..... one thing I noticed was the schematic showed ..panel light driver.... went into the temperature control. I had already noticed ...the dimmer you turn the dash lights........ the cooler it gets...... strange..... so.... on an outside chance, I unhooked the negative battery cable for an hour then hooked it back up. It solved the problem for 2 days. Now it's back to the same thing. I know it is shutting a door instead of turning a heater valve on because I started it cold the other morning and it wasn't a great amount of heat like normal..... just ambient air temperature. I am leaning toward a faulty BCM........
     
  7. Jul 11, 2017 at 7:15 PM
    #7
    JKBob 25

    JKBob 25 Well-Known Member

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    The one thing I recently wished I had paid more attention to and learned more about....is electrical issues. Manya years ago blew a fuse in my 67 Chevy Impala. Stuck the foil wrapped fuse back in it. An hour later I had a fire. Should have made me want to learn more. Lol.

    Back to your issue. Dealership manuals is a Great place to start kymartin6. Good luck. I am watching this thread in an effort to learn. So please post your findings. Thanks.
     
  8. Jul 11, 2017 at 7:45 PM
    #8
    kymartin6

    kymartin6 [OP] Member

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    If I unravel the secret....... I will most certainly let everyone know...... It might help someone later with a similar problem...... :)
     
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  9. Jul 11, 2017 at 7:50 PM
    #9
    JKBob 25

    JKBob 25 Well-Known Member

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    Agreed. Hope you hang around here. It's an awesome forum. And I see you have a sense of humor. Good to have with some of the members here. :eek:
     
    chris4x4 likes this.
  10. Jul 12, 2017 at 6:37 PM
    #10
    kymartin6

    kymartin6 [OP] Member

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    Thanks Bob....... yeah, I plan on sticking around. Lots of good folks and information here.


    As far as the sense of humor....... as a friend of mine says..... ''If you don't learn to laugh at trouble..... you ain't gonna' have nothin' to laugh about''........ :)
     
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  11. Jul 12, 2017 at 6:42 PM
    #11
    JKBob 25

    JKBob 25 Well-Known Member

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    So true dude. So true. And yes. A lot of great guys here. We have fun with it.
     
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  12. Jul 12, 2017 at 6:44 PM
    #12
    chris4x4

    chris4x4 With sufficient thrust, pigs fly just fine Moderator

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    Not sure if we have any "great" guys on here....I would say most are "Marginal"..........and the girls are acceptable thus far......




    :bikewheelie2:
     
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  13. Jul 12, 2017 at 6:50 PM
    #13
    JKBob 25

    JKBob 25 Well-Known Member

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    Ok, yeah Chris is right. I was trying to be a nice guy and make us look some what normal. :alien:
     
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