So normally when you want to test your fuses, you set the car to on and put the tester clip to ground then put the tester's lead on the fuse. if it lights up then the fuse is working. Well, even when I remove the car key, the tester light still comes on. This seems to indicate a short somewhere. Also when I measure the current with a multimeter by disconnecting the negative lead on the battery, it shows about .8A with the car off. Also, when I reconnect the negative lead to the battery, sometimes it activates the car like it would drive the radiator fan for a second or some other electrical parts. There's also loud clicking noise like the starter is engaging but only for a second. Does anyone know what's going on?

  • 3
    What's the actual problem you are trying to fix? Jun 11 '13 at 17:52
  • Sounds like he is testing for parasitic load but not sure why he is checking the fuses.
    – Mike Saull
    Jun 11 '13 at 21:33
  • 1
    When checking the draw, you need to let it sit for 5-45 minutes depending on the car to allow certain modules to power down. After that time, you should expect less 50 mA (.05A). .8A when first connecting the meter after having removed the terminal is typical - but must let it sit and then check to be sure. Things powering on when reconnecting is fairly normal as well. What brought you to checking all this? Jul 10 '13 at 5:19

That just means that particular circuit is an always on circuit and not switched by the ignition.

When you reconnect the battery lead the computer is probably doing a power on test and as such some relays are being activated such as testing the fan etc.

  • ok what about the fuses then? why are they always on even though the power is off? all of them are on. also, the .8A power draw is too high.
    – Alan
    Jun 11 '13 at 21:09
  • Maybe there is a bad relay? Are you sure you are testing the parasitic draw with all of the doors closed trunk closed and without the key in the ignition. Start by replacing the relays in your fuse boxes.
    – Mike Saull
    Jun 11 '13 at 21:28
  • yes, nothing is on. however, i do have a remote starter. i don't know if that requires power to monitor a radio input from the remote. when you say, "replace the relays" do you mean pull it out one by one to see what is causing the power draw? as for the question you have above "not sure why he is checking the fuses," i wanted to see which fuse the power draw was going through but it turned out that all the fuses lit up the tester probe. this is with no key in the ignition so there should be no power to most of the fuses except the short, but all the fuses lit up.
    – Alan
    Jun 11 '13 at 22:53
  • 2
    Just because the fuse is hot doesn't mean there is power going through it. It may be that there is a switched ground to whatever accessory it powers. You need to pull relays and fuses until you see the .8A drop. once you see a drop you know that is the circuit that is drawing the current. Find out what that circuit is and find what is causing the draw.
    – Mike Saull
    Jun 12 '13 at 15:02
  • @MikeSaull good point about switched grounds. Could also simply be switched downstream of the fuse (but still on the +12V side of the load)
    – mac
    Jun 13 '13 at 0:19

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