current drain | FerrariChat

current drain

Discussion in 'Boxers/TR/M' started by bpcurtis, May 6, 2022.

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  1. bpcurtis

    bpcurtis Karting

    Nov 5, 2003
    79
    Dickinson, TX
    Full Name:
    Burnell P Curtis
    My 87 testarossa has always had a current drain because it would have a dead battery after a week. I determined that I was going to find the problem. I disconnected the battery ground and put an amp meter in the circuit. I then pulled each fuse one at a time. The 0.16 amp would go to 0.06 amp when fuse 2 was pulled. No others affected the amperage. Fuse 2 is door lights and interior lights. I then opened the door and the amps jumped to 2.56amps. I took the puddle light and end light out and the amps dropped to 2.46amps so the problem is not in the door but in the interior. I then went to the other door and got the same results, confirming it is in the interior. I went to the footwell on the passenger side and disconnected the 4 connections (one at a time) with no change. The 4 connections are on the floor in a metal holder.
    I am at a loss.
    Suggestions!!!!
    Thanks,
    Burnell Curtis
     
  2. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,825
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    Are you sure that the roof lights are turned "off"? The spot light is easy to tell if it's "on" or "off", but the larger zone light looks about the same whether "on" or "off" ;)

    Always possible that you've got some wiring modification/additions. Fuse #2 is an always +12V thing and that is often useful for added electrical stuff. The RN (red-black) wires at the end of the k horizontal white connector at the bottom of the fuse-relay panel is where/how current leaves fuse #2 so you might have a look at those wires to see if anything has been "pirated" off of those wires.
     
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  3. bpcurtis

    bpcurtis Karting

    Nov 5, 2003
    79
    Dickinson, TX
    Full Name:
    Burnell P Curtis
    The dome light is on but it is off when the door is shut and when open is on but could not possibility draw 2 amps. The spot lights on the roof are off and when on draw little amperage. I will check the fuse relay panel to see if something has been added. In summary, nothing is suppose to be on this circuit that draws that much amperage.
    Thanks
     
  4. Basal Skull

    Basal Skull Formula Junior

    Oct 26, 2010
    427
    Vancouver BC
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  5. flash32

    flash32 F1 Veteran

    Aug 22, 2008
    6,941
    Central NJ
    Full Name:
    Dominick
    I seem to remember that some connect radio and had one TR that the radio drained battery

    Sent from my moto g power using Tapatalk
     
  6. bpcurtis

    bpcurtis Karting

    Nov 5, 2003
    79
    Dickinson, TX
    Full Name:
    Burnell P Curtis
    My TR had an alarm system and I took it out. It also had an aftermarket sound system that I took out. I have unplugged every device in the console and no effect on the current drain. I unplugged the harness at the right of the passenger's feet and the draw dropped 1.5 amps so that means that part of the draw is before the harness and part after. My radio is on fuse 5 and is unplugged for this test. I am out of ideas intil I get some inspiration. My guess is that the people that installed the alarm system or the sound system used the wrong wires but to power what presently???
     
  7. bpcurtis

    bpcurtis Karting

    Nov 5, 2003
    79
    Dickinson, TX
    Full Name:
    Burnell P Curtis
    Most of my problem is solved. The dome light draws more that 2 amps. I opened it up and there are 8 tube lights and they draw lots of current. If you want to test yours, you get to the bulbs by bending the plastic cover in the middle and slipping the front of the plastic out of slots. The plastic sheet has two tabs on the front that goes into the slots. Do not try and remove the whole piece of plastic as it holds the three switches and you could break the small edge holding the switches. My problem is not solved as fuse 2 draws 0.17 amps with the doors shut and this is too much. Does anyone know if the door switch controls anything in the engine compartment? The drawings are hard to read.
    Thanks.
     
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  8. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,825
    30°30'40" N 97°35'41" W (Texas)
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    Steve Magnusson
    No, nothing in the engine bay, but fuse #2 does also run the door lock actuators. You can rule both doors in, or out, by unplugging the C1 connector (LH door) and the C9 connector (RH door). Here's the C1 connector location (and C9 is in a similar place on the other side):

    Image Unavailable, Please Login

    I believe fuse #2 also supplies the overhead console switches (which are really self-latching relays) -- rear heated window switch and fog lights switch.
     
  9. turbo-joe

    turbo-joe F1 Veteran

    Apr 6, 2008
    9,540
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    romano schwabel
    I think only when ignition is on. not in off position
     
  10. Qavion

    Qavion F1 World Champ
    Silver Subscribed

    Feb 20, 2015
    14,308
    Sydney
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    Ian Riddell
    Including the cigarette lighter?

    This wiring diagram may be easier to read:

    https://www.dropbox.com/t/lkxSSRX15UCHMJ1C
     
  11. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,825
    30°30'40" N 97°35'41" W (Texas)
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    Steve Magnusson
    Those switches operate only when the key is "on", but they still have the always +12V wire from fuse #2 connected to them.
     
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  12. turbo-joe

    turbo-joe F1 Veteran

    Apr 6, 2008
    9,540
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    but the 12 V will end there I think
     
  13. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,825
    30°30'40" N 97°35'41" W (Texas)
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    Steve Magnusson
    Yes, if everything is not broken and nothing is modified. Was just listing "where" the output of fuse #2 goes, not how it is used.
     
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  14. bpcurtis

    bpcurtis Karting

    Nov 5, 2003
    79
    Dickinson, TX
    Full Name:
    Burnell P Curtis
    Problem found. The 0.17amps is being drawn by the drivers side door locking mechanism. Mine does not work and I have to lock the car manually. Does anyone know that the normal draw would be? If you are curious, just take the neg terminal off the battery, but an ampmeter between the battery and cable, and then take apart the c1 terminal, which is located by the brake booster. Whatever is measured is used by the lock mechanism. Doors closed of course.
    Thanks everyone. If I knew that the current drain was abnormal, I would open the door and fix it. Otherwise, maybe not.
    Burnell
     
  15. turbo-joe

    turbo-joe F1 Veteran

    Apr 6, 2008
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    romano schwabel
    good you found the mistake, now only to check what is wrong
     
  16. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,825
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    It's definitely abnormal. My TR has a total parasitic current draw of only .065A with both door actuators still connected. As you've already found, 0.170A is almost unlivable -- even my .065A is a little annoying and would be better to be less.
     
  17. bpcurtis

    bpcurtis Karting

    Nov 5, 2003
    79
    Dickinson, TX
    Full Name:
    Burnell P Curtis
    Here is the bad part Image Unavailable, Please Login 8Iis the part connected to the drivers side lock mechanism. When I unplugged it my current draw went almost to zero (radio fuse out but clock in). My radio draws a lot, about 0.15. I will look for another of the above but have little hope of finding one. One of the circuit boards is burned on this one. Oh well, not having auto lock of passenger door is not too bad.
    Thanks everyone
     
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  18. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    26,825
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    You might try contacting the F dismantlers for a used one (it's the kind of component that could survive a bad crash) -- new ones are available, but pricey.

    That seems a rather excessive current for something that would normally only be maintaining a memory and/or running a clock -- do you have the wiring instructions to ensure that someone hasn't (wrongly) connected something that should be +12V with key "on" to something that is +12V always?
     
  19. turbo-joe

    turbo-joe F1 Veteran

    Apr 6, 2008
    9,540
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    romano schwabel
    can you please post a photo from the complete item? as I see it it is the same as in lancia thema
     
  20. samsaprunoff

    samsaprunoff F1 Rookie
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    Jun 8, 2004
    4,464
    Edmonton, AB Canada
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    Sam Saprunoff
    Good day,

    Depending upon how damaged the board, it might be repairable. From the pic you posted, the electronics are not overly sophisticated and so it could be a pretty straightforward repair.

    Cheers,

    Sam
     
  21. bpcurtis

    bpcurtis Karting

    Nov 5, 2003
    79
    Dickinson, TX
    Full Name:
    Burnell P Curtis
    Here is a photo of the unit. I do not know if it crosses to a lancia. Sam, I gave up repairing circuit boards long ago, for good reason. Now, does anyone know why my speedometer and odometer pegs out and I have a sending unit that is two years old. Image Unavailable, Please Login 9
     
  22. samsaprunoff

    samsaprunoff F1 Rookie
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    Jun 8, 2004
    4,464
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    Sam Saprunoff
    Good day Burnell,

    Can I ask, what is/was the good reason to not repair? In some cases the replacement item is inexpensive and so no real motivation to repair. However, in othre cases if the damage is not too severe and/or if the tech is pretty straightforward, then a repair can make fiscal and logistical sense... especially now with so many of the devices being out of stock because of supply chain issues.

    Cheers,

    Sam
     
  23. bpcurtis

    bpcurtis Karting

    Nov 5, 2003
    79
    Dickinson, TX
    Full Name:
    Burnell P Curtis
    The reason to not repair is I am very bad at repairing circuit boards, I usually not repairing them and ruining them.
    Burnell
     
  24. vincenzo

    vincenzo F1 Rookie

    Nov 2, 2003
    3,373
    ummm…. Driving too fast?

    ;)
     
  25. samsaprunoff

    samsaprunoff F1 Rookie
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    Jun 8, 2004
    4,464
    Edmonton, AB Canada
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    Sam Saprunoff
    Good day Burnell,

    Gotcha. In my case if it was not broke when I started it will be when I am finished :)

    Cheers,

    Sam
     
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