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Ford car stereo F87F-18C815-BB drains car battery.

Discussion in 'Electronic Repair' started by David Farber, Mar 12, 2013.

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  1. David Farber

    David Farber Guest

    I was given this Ford F87F-18C815-BB factory tuner/cd player to see why it's
    draining the car battery to the point where the car won't start. It has
    already been removed from the car. I found the pin outs here: According to the owner, only
    the antenna and J1 were being used. By the way, since the radio has been
    removed from the car, the battery does not abnormally discharge.

    It's been a while since I've powered up a car stereo. Do I need 12V on pin 3
    (start), pin 4 (clock), pin 9 (battery), pin 10 (run:acc)? Is the "clock"
    the actual time of day display or is it the internal clock for the system
    processor(s)? Are pins 1 and 2 (illum +/-) just the 12V input that power
    whatever accessory lights there are? Can that be jumpered to the 12V line as
    well? Is it ok to common ground the illum - pin to pin 11 (radio
    gnd)?Basically I want to begin by putting it in standby mode and measuring
    the current. Also, does anyone know where to get a schematic for this unit?

    Thanks for your replies.
  2. Guest

    This radio appears to be for a late 90s-mid 00s Ford. If the car still
    has the factory battery, replace it. If the battery that's in there now
    is more than 5 or 6 years old, replace it. You and the car owner will
    be happier. :)
    My guess: apply power to pin 9 only to simulate the key off position.

    Apply power to pins 9 and 10 both to simulate the key on position.

    I don't know what pin 3 (start) does, but I suspect it might be for
    "load shed" when you turn the ignition key to "start", so the engine
    starter gets the maximum possible juice. Some cars do this by having
    two different "run" wires from the ignition switch - one gets dumped in
    "start" and the other doesn't - but I can see them just using the
    "start" wire as a disable as well.
    "Clock" is probably either a constant +12 V to keep the clock running,
    or maybe it has to do with when the clock is displayed. (Like, maybe
    the body computer sends 12 V to it when you open the door, so the
    clock comes on with the dome light.) If it's constant 12 V, then I
    don't know why it doesn't just use pin 9, but maybe they wanted to put
    it on a different circuit.
    In the car, they may get fed from a rheostat or PWM box so as to have
    something less than 12 V on them. You might apply something like 6 to
    8 V DC to pins 1 and 2, only, and see if the display or buttons start to
    light up. If that looks good, then ramp up to 12 V. If 12 V looks
    good, then yeah, you can just connect pin 2 (illum -) to pin 11 (radio
    ground) and pin 1 (illum +) to either pin 9 or pin 10. If 6 or 8 V DC
    makes the display or buttons light up insanely bright, then go down on
    the voltage a little.
    It probably exists on two hard drives at Ford (or their supplier) and
    nowhere else. A few repair places, like the one you linked, may have
    one, but they probably want to repair your stereo for you rather than
    give (or sell) you a copy of the schematic. I wouldn't hold my breath
    waiting for one.

    Matt Roberds
  3. David Farber

    David Farber Guest

    Hi Matt,

    I powered up the unit with by putting 12V to pins 9 and 10. With the unit
    powered on and no load or signal, the draw was about 545ma. In standby mode,
    the current draw was about 4.5ma. I was checking the illum terminals and
    decided not to put 12V to illum + and ground because illum - terminal was
    not grounded. However I did put an ohmmeter across the + and - illum
    terminals and it was 4.2 ohms. There are 12 lamps on the display board. They
    are not in parallel.

    I'm going to reinstall the radio tomorrow and see how these numbers compare
    to the current drain from the car battery.

    Thanks for your reply.
  4. gregz

    gregz Guest

    I have no idea of possible similarity. I troubleshot a 95 olds running
    battery down. Auto antenna down sensor was bad, producing occasional pulses
    to antenna motor. I disconnected motor.

  5. Guest

    About 6.5 watts... that seems reasonable.
    This shouldn't kill a car battery in good condition. I have heard
    various numbers for the acceptable "key off" draw on a car battery but
    20 mA is usually somewhere in the ballpark. This is for everything in
    the car - the radio station memory, a clock, anything the ECU needs,
    security system, etc. 20 mA is 0.48 amp-hours a day, or 6.7 Ah in two
    weeks. A car battery is very very roughly 50 Ah plus or minus [1]; with
    6.7 Ah gone it will probably still start the car. ("Airport time" is
    one name for this - you should be able to leave the car at the airport
    for X amount of time and it should still start when you get back.)
    You might poke at the harness side of the connectors with a 12 V test
    light before you reinstall the radio. Maybe it's not getting the
    message that it could go into standby - short to battery power on the
    "hot in run" line?

    If this car has any aftermarket stereo equipment wired to the factory
    head end, you can assume this was done incorrectly and be right about
    half the time. Other sources of automotive electrical fun include
    aftermarket trailer hookups and driving lights.

    If the car has a trunk light or underhood light, look to see if it's
    shutting off correctly when the trunk/hood is closed. This can be
    a hard-to-catch source of battery drain.

    Matt Roberds

    [1] Yes, I know they are not rated by their manufacturer or sold this
    way. If you use one like a deep-cycle battery instead of a starting
    battery, you get roughly 50 Ah. Yes, it's not a good idea to use a
    starting battery like a deep-cycle. The 50 Ah number is just there
    as a reference for things like this.
  6. micky

    micky Guest

    Except then, the radio would likely keep playing. Even if it had a
    separate amplifier, that amp is probably on when the radio is on

    But even if no sound came from the radio, if the power were on, the
    station display would be on, and seek and scan, etc. would work.
    Or glove box light.

    Hard to belive, but I once installed two burglar alarms in the same
    car, and that ran down my battery. I thought the second was just a
    pager transmitter that would run only when the first alarm told it to,
    but it turns out it was sensing current changes all the time.

    However, in this car the problem went away when the radio was out, so
    if the problem comes back when the radio's back in, and out when it's
    out again, that's a big clue it's the radio.
  7. David Farber

    David Farber Guest

    This turned out to be quite the adventure. I got a little more information
    from the owner. The problem started when the parking brake was pushed down.
    (It uses a foot pedal for the parking brake). Somehow her foot dislodged the
    connector going to something around the clutch pedal shaft. It has six
    terminals and I'm guessing it's some sort of sensor that detects the
    position of the clutch so you can start the car? I removed the plug and
    checked for damage. It looked fine. I did take a reading of the battery
    current before I put the radio back in with everything off before I started
    troubleshooting. The reading was 0. Then when I was using my meter later on
    I noticed that the DCV button was pressed in and not the DCAmps. At some
    point I measured .22A from the battery. I put the radio fuse back in
    (somebody had pulled it out so the radio wouldn't be draining the system)
    and measured the current. I jumped two about 2 amps. I wasn't writing this
    stuff down but I think that's what it was. Next I pulled the radio out again
    and left the fuse in. It was still reading too high. Then I pulled the fuse
    out and it was still reading too high. Huh? I proceeded to turn "off"
    (though I can't specifically remember that it was even lighting up) the dome
    light by moving the dome switch to one side. It's a three position switch so
    I figured one of the other choices was always off and the other position
    would be always on. The light didn't come on so I figured I made the right
    choice. Later on I found out that those other two positions of the switch
    were for, always on left lamp and always on right lamp. All these little
    details that you don't think about beforehand.

    So now both doors are closed to make sure the dome lamp won't come on. The
    radio and Fuse 29 is removed. The current from the battery is in the 1.8 amp
    range. Great. I've done nothing but inspect the system and things are
    getting worse. Then I looked at the schematic
    There were four other lines that distributed standby power to the car. They
    were the cigarette lighter, flasher, instrument panel, and generic
    electronic module / central timer module. I pulled those fuses one at a time
    and went back and measured the current. After pulling the lighter fuse, the
    current drop to about .8A. Pulling the flasher fuse had no effect. Pulling
    the instrument panel fuse lowered it a bit more, and then pulling the last
    fuse dropped it down to near nothing. I put on my magnifying glasses and
    took a good look at the cigarette lighter. There was some rust or corrosion
    in there. By the way, the receptacle itself was not covered/protected so it
    made sense that it was getting to look a bit rusty. I took a sharp ended
    pick tool and started to scrape away at the corrosion. I put the fuse back
    in and the current didn't spike up. In fact with all the fuses put back in,
    the current leveled off at .22A. I didn't know if this was an acceptable
    reading or not. One of my friends was visiting with me so I asked him if I
    could remove the battery cable from his 2001 Honda and check how much
    current was flowing from his battery in standby. It was identical .22A. I'm
    still waiting to hear back from the owner if the battery made it through the
    night or it had to be jump started. That's usually good news when somebody
    doesn't call you back when you ask them if your repair went well, isn't it?

    Thanks for your reply.
  8. Guest

    Yeah. There will be at least one contact that doesn't close until the
    clutch pedal is fairly far depressed; it is there to prevent the starter
    from running unless the driver has stepped on the clutch. (It also
    prevents a smart driver from doing something clever, like using the
    starter to "walk" the car out of an intersection, off the railroad
    tracks, etc.) If the car has cruise control, there will be another
    contact that changes state when the clutch pedal is barely depressed;
    that one is there to cut out the cruise control if the driver uses the
    This is a good way to get lost in the middle of an adventure. :)
    This page has been saved by Internet Exploiter... as an email... with
    Quoted-Printable damage. Maybe the least useful format that it was
    possible to use, which explains why it's IE's default.
    Does the car have more than one cigarette lighter socket? An extended-
    cab pickup might have an extra one in the back seat. Sometimes people
    add one in the bed for accessories... sometimes they even get it on the
    same fuse as the one in the cab!
    I have seen new cars that had a "no smoking" package from the dealer;
    the "ashtray" had a flocked lining to serve as a small storage bin, and
    there was a plastic plug with handle in place of the cigarette lighter
    element. If the lighter socket on this car is in a place where it is
    liable to get drinks and debris in it, finding one of those plastic
    plugs (dealer? junkyard?), or a rubber stopper with a bolt in it for a
    handle, might be a good idea.
    That's kind of high. In 24 hours that is 5.28 Ah gone from the battery.
    That will run the average car battery down to nothing in about ten days.

    Some cars have solenoids on the front seat belt reels that allow the
    reels to spin more freely when you are getting in and out of the car.
    Usually, as soon as you hit the unlock button on the remote or open the
    driver's door, the solenoids will turn on. They stay on until either
    1) the engine starts or 2) a timeout in the range of 5 to 15 minutes
    expires; if you are standing there with the engine not running, you can
    sometimes hear a little "tick" from the seat belt reel when the solenoid
    turns off. This might account for some of the current draw you are

    A few newer cars start getting lots of things ready for you when you
    open the driver's door. Toyota hybrids will turn on the electric
    vacuum pump (which provides brake power assist when the engine isn't
    running) and possibly a few other things before you have turned the key.
    These eventually time out as well, but the current draw from the 12 V
    battery might be surprising for the first minute or two.

    Matt Roberds
  9. gregz

    gregz Guest

    20 ma. Is about the max draw, everything off. .020 A. I had one power amp
    that drew 35 ma. With a poor battery, it would drag it down within a week.

  10. micky

    micky Guest

    That's actually a better design. If your hydraulic brakes fail, hold
    the foot brake release handle so the brakes don't lock and then use
    your foot to apply the "hand brake", "emergency brake". . You can
    use it like the regular foot brake. I hate the hand brake between
    the seats.
    On some cars there are 3 fuses for the radio. GM, for example. I
    think you talked aobut this before. One for the clock, so it doesn't
    stop when the car is turned off, one for the dash lights,, and one for
    the radio itself.
    When you're miy age, you'll write it down. But I give you a lot of
    credit for using a meter. It's hard to get anyone to use a meter.
    (Anyone who doesn't read SER, at leat)
    I know that feeling. When I was 19, the first week I had my '50 olds,
    the battery was dead every monring and I had to take my mothers car.

    Short, Doconnect, Short Disconnect, Short, Disconnect, no short!!!
    Reconnect last disconnected wire. No short, Reconnect wire before
    that , No short, Reconnect wire before that. No short.

    Up and down, up and down, 3 or 4 levels, 3 or 4 found tirps, and in
    1950 there were no quick disconnects.

    Finally found it. Glove box light. Every time I got close, I opened
    the glove box to get something and if it was closed well before, I
    closed it badly. If it was closed badly, I closed it well. That was
    also what drained the battery.
    Snmeone may have wired something to the cig lighter circuit. I use
    that alot because I almost never use the lighter, so it doesn't
    interfere with add-ons.
    If you have a decimal point, please put a zero in front of it. With
    my monitor, it's about the only way I can tell it's there. Right now
    it looks like 22 amps.
    I suppose so.
  11. micky

    micky Guest

    There was a caller on Cartalk where animals shorted the starter cable
    and the car moved "down the driveway" which was up a hill, across t he
    street, and almost went over a cliff.
    Hey, did Indiana Jones take notes?
    What the heck is .mht and how come IE reads it but maybe not Firefox?
    I think I remember Pat Voss saying that if a #54 light bulb would
    light with the current going out of the battery, it was too much. #54
    is the smallest spherical lne, back when lightbulbs were lightbulbs
    and didn't speak some European or Asian langueage. Someday I have to
    find out how many hundredsths of an amp is a $54.
    Good to know. I will proably be able to use this in about 7 to 9
  12. gregz

    gregz Guest

    I always have problems with left push down brake. I never had problems with
    right center pull handle system. One fault is left hand salt corrosion.
    Sometimes they not release. Sometimes you got to pull up to turn lamp off.
    I'm always afraid to use the push emergency brake. It's mostly a parking
    hold brake, if it works.

    I thought dome light, was a Pittsburgh thing.
    It should be a hood light, Britain.

  13. gregz

    gregz Guest

    Looked for #54 nope. I used to have lamp tables. Google can be useless on
    old stuff.

    I hate when I open the door on my avalanche, and I hear the navigation disk
    being read. Key off.

    I once had a ford leaking amperage. Found leaky brake switch. Light was on
    dim in the dark, sometimes.

  14. David Farber

    David Farber Guest

    Excellent point about the leading zero when displaying numbers less than
    zero. I will adopt that format.

    I finally did get in touch with the owner and I was told that the battery is
    holding up quite nicely. I probably should have mentioned that during the
    initial inspection, there was a bit of corrosion on the positive battery
    terminal post which was cleaned off. The connecting terminals to the battery
    cables were also cleaned.

    Thanks for your reply.
  15. David Farber

    David Farber Guest

    Somewhere in my shop I used to have a book will those bulbs listed. I'm
    fairly certain it had current ratings. I'll do some hunting and let you
  16. Guest

    Somewhere around here I have a Wagner Lighting catalog (on dead tree
    slices) that has most of the automotive lamps in it. I was looking for
    an update to it recently and found ,
    whose interior pages look almost exactly like the Wagner catalog.

    Unfortunately the Sunray catalog above doesn't have a #54. #53 is a
    G-3.5 bulb (0.463" sphere) rated at 14.4 V, 0.12 A, 1.0 mean spherical
    candlepower. #55 is a G-4.5 bulb (0.588" sphere) rated at 7.0 V,
    0.41 A, 2.0 MSCP.

    Hmm... says #54 is
    G-3.5, 12 V, 1 A, 12 W. Somehow I kind of doubt 12 watts in this size

    Standard disclaimers apply; I don't get money or other consideration
    from any companies mentioned.

    Matt Roberds
  17. micky

    micky Guest

    Thanks for the effort. You're going to kill me. It may have been a
    #27, half of 54, or even something else. I have one in a toolbox,
    complete with a socket and a couple wires.. If I can find it, I'll
    post the bulb number and the resistance.
  18. micky

    micky Guest

    That's true. Although I t hink the net is the underlying problem.
    I worked in an election in 1970 where we lost by 4 votes out of 50,000
    cast, and there's basically nothing about it on google. (And even
    though I was from out of town, I talked to 4 people the next day who
    said they meant to vote for my guy, but didn't get around to it. )
    Wow. Bad switch design, I guess. I can imagine a closed switch not
    being well closed, but open should surely be open. I guess I should
    check my brake lights now.
  19. Guest

    It's just 12 volts... wear rubber gloves if you're that worried. :)
    Well, the cold resistance. I measured an 1157 tail lamp bulb hot and
    cold and the hot resistance was 11 to 12 times greater than the cold.

    Matt Roberds
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