06 Ram 1500 won't start unless I bang on my A/C compressor?

HangmansJokeHangmansJoke Ontario, CanadaMember Posts: 5
edited June 2017 in Dodge
I'm confused. And I've had a hell of a time trying to figure this out.

I have a 2006 1500 Sport with a 5.7 Hemi and I can't get it to even offer up
anything unless I have someone turning the key while I bang on the a/c

I've paid through the nose already to have my SKIM key reprogrammed
and the remote starting system checked out. Everything's good there.
(however this might have been a waste now that I've discovered this)

I don't have to hit it too hard, I just have to keep hitting it until the engine
turns over.

Is there anything around the compressor that I could be jarring enough to
get it to start? IE: sensor or relay?

I'm good with electronics and computers, but I really miss my 2nd gen right
about now!

Any guesses??


  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    How peculiar.

    If it were my car, I'd do two experiments:

    1. Disconnect the compressor clutch electrical plug and then see if it starts when you hit the compressor.

    I think it will start

    2. Try hitting some other part of the car in close proximity to the AC compressor.

    I'm wondering if all you're doing here is jarring some stuck relay.
  • thecardoc3thecardoc3 Member Posts: 5,465
    Do you have a voltmeter? Have someone else turn the key when it won't start and with the black lead on the negative battery post, touch the body with the red lead. You should measure 0v. Then touch the engine block with the red lead, it should be 0v. If either of those show higher voltage then you have a ground cable issue. If they both check ok, then from the battery negative post first measure the battery voltage. Then follow the different parts of the positive cable, and to and through the fuse block if necessary to see where voltage is dropping.
  • HangmansJokeHangmansJoke Ontario, CanadaMember Posts: 5
    My gut was telling me a stuck relay, but it's been suggested more than once to check my ground. It's pouring rain here this morning - I'll test the ground after work if weather permits and post my results.
  • HangmansJokeHangmansJoke Ontario, CanadaMember Posts: 5
    Disconnecting the wire from the compressor didn't help start the engine, I still had to hit it with a hammer to get it turned around in the driveway. Turned it off and tried again, nothing.

    So, I cleaned and reattached 2 ground wires running from the battery and it sort of fixed the issue. There's a 3rd right behind the power steering reservoir that won't budge. (I'll try that one again when I have a day off.)

    Trying to remote start simply doesn't work, I checked the unit and it looks like it needs reprogramming (no matter, I can just use the key)

    I can start it over and over but I let it sit for 10 minutes and tried again.... it fired up but there was a high pitch grinding sound before the engine kicked in.

    I'm going to let it cool right down and try to start it again in an hour and post the result.
    (If it's dead, then I'll bust out the volt meter and check the connections.)

    Thanks for your suggestions! I never would have thought to look at a grounding issue if it weren't for this forum.
  • HangmansJokeHangmansJoke Ontario, CanadaMember Posts: 5
    Ran a new ground wire from the negative post to a grounding point behind the power steering reservoir. Still no ignition unless I tap the compressor, BUT, the starter now tries to turn the engine where it didn't before and it's not sounding the greatest (will grind every start before ignition.

    Also, after starting by tapping the compressor, I can shut the engine off and turn it on again without much trouble (aside from the starter whining before ignition) AND the battery gauge rises SLIGHTLY when I push the gas and drops when I release. Battery gauge is JUST above half when the engine is on.

    Could a bad ground be causing my starter/ignition issue or is the starter dying and that's been the reason for everything?

    Mr_Shiftright: I can't seem to find any switches or relays on the area of the compressor. there appears to be some sort of sensor wire under the compressor that I can's get to without pulling the compressor and voiding the lines. Any idea what might be in the area?

    I'm totally lost here. If i had any hair left I'd be tearing it out! I'm starting to think I'll need a new compressor AND starter by the time I'm done.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    What size "new" ground wire did you run?

  • thecardoc3thecardoc3 Member Posts: 5,465
    edited April 2016
    If you keep banging on the compressor you will need a new one.

    Taking apart wiring connections and cleaning them without first testing and proving that there is a voltage drop across them while the symptom is occurring is guessing. Get a some schematics for the affected circuits, identify what voltages should be a given points when the circuit is operating, then go make measurements and confirm where the circuit is failing at.

    Remember when you wrote this? "I'm good with electronics and computers, but I really miss my 2nd gen right about now! Any guesses?? "

    Test, don't guess.

  • HangmansJokeHangmansJoke Ontario, CanadaMember Posts: 5
    New Starter.

    I'm not going to spend too much time on why hitting the ac would fire up the starter, but i replaced it and havent had a problem in days.
  • Mr_ShiftrightMr_Shiftright Sonoma, CaliforniaMember Posts: 64,482
    I'd call in a high priest or shaman to deal with this one. B)
  • datdodgedudedatdodgedude Member Posts: 2
    I know I'm a bit late on this lol but did you try to take the compressor out to check the pulley? They can get stuck and make the whole vehicle not turn on
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