Announcement

Collapse
No announcement yet.

WTF? Car dies when brake lights or turn signals are on.

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

    WTF? Car dies when brake lights or turn signals are on.

    '90 325i, stock electronics except I'm running a Mark D chip and the motor/harness are from an '89.

    Like it says, whenever the brake lights come on or I use turn signals, the car sputters and dies. Like it runs out of fuel. Also, when I push the brake pedal with the car not running but in the on position, the gas gauge drops to E (with a nearly full tank). Let off the brake, gauge pops right back up. Once I've activated the brake lights, then all brake lights and turn signals stay dimly lit.

    When driving it, it runs perfect most of the time. When I touch the brakes or signal it then starts to sputter and will die if I don't let off the brake immediately or tun off the signal. Once I used the signals/brakes the car will not run properly, it acts like it's starving for fuel. Then I can usually turn the car off then back on and it will run properly again. Though this trick hasn't worked the last few times.

    When I test the tail light connectors during this dimly lit behavior, I'm getting between 4 to 8 volts without the brakes applied and without the turn signals on. I tested the thick brown ground wire in the harness that runs under the back seat, it shows about 8 volts when I ground the voltmeter to the chassis.

    I'm pretty sure I have a short somewhere with a power wire touching the chassis, but my only clue is that it's probably somewhere in the rear of the car since it only seems to be affecting brake lights, signals, and fuel pump/sending unit.
    90 325i DD/Track
    03 Durango 5.9


    Originally posted by e30mpg
    It is recommended to get new gasket but this is R3v and we just copper spray that shit......slap biotch on and tighten to tq.

    #2
    It sounds like there is a bad connection at the ground on the left side of the car behind the rear seat back.
    The car makes it possible, but the driver makes it happen.
    Jim Levie, Huntsville, AL

    Comment


      #3
      I did briefly look in that area for a ground connection. Didn't find it, but I didn't look very well. I'll check it again. I'll pull the seat back, I've only looked under the seat bottom and in the trunk thus far. Thanks Jim for the quick response.
      90 325i DD/Track
      03 Durango 5.9


      Originally posted by e30mpg
      It is recommended to get new gasket but this is R3v and we just copper spray that shit......slap biotch on and tighten to tq.

      Comment


        #4
        The ground wire for the harness was not connected to its usual location behind the seat back. It was under the rear "door" card in what appears to be a drilled and tapped hole. It was not connected at all so it was only grounding when it happened to touch the chassis.

        Issue resolved. Thanks again Jim.
        90 325i DD/Track
        03 Durango 5.9


        Originally posted by e30mpg
        It is recommended to get new gasket but this is R3v and we just copper spray that shit......slap biotch on and tighten to tq.

        Comment

        Working...
        X