1999 550 Tail Lights, Back-Up Lights and Radio Speakers Not Working | FerrariChat

1999 550 Tail Lights, Back-Up Lights and Radio Speakers Not Working

Discussion in 'Technical Q&A' started by FPFaeth, Apr 5, 2014.

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  1. FPFaeth

    FPFaeth Formula Junior

    Dec 3, 2009
    663
    NY
    Full Name:
    Frank Faeth
    #1 FPFaeth, Apr 5, 2014
    Hi,

    I originally posted this on the 550 forum but received few responses, so thought I'd try here.

    I have a 1999 550 Maranello which has been bullet-proof (except for the two ECUs in the engine compartment that connect to the catalyst probes) for over 42,000 miles. However, out of the blue, the tail lights, back-up lights and speakers (though radio turns on) stopped working. I checked: the bulbs themselves, the fuses (#10 and #11), and replaced letter P, which I presume is a relay, with A, which seemed to be the same type (bare metal as opposed to having a plastic casing). No effect. Everything else works -- headlights, parking lights, side lights, emergency flashers. Brake lights work too.

    An update on the tail lights, after a visit to my garage (top notch; understands Ferraris) a few days ago:

    1) Both tail lights do not work.
    2) Back-up lights do not work.
    3) Radio turns on but speakers do not work.
    4) Fuses and relays and all sockets work and bulbs are fine.
    5) Fuse/relay panel is clean, dry and checks out electrically.

    We learned (via testing and also via the wiring diagram) that the left and right side of the car operate the tail lights and back-up lights independently, so it's likely to be something electronic they share in common to cause these problems, which occurred out of the blue. While it could be a short in both wires, my guess is that this is unlikely.

    They mentioned a body movement module/sensor as a potential source of the problem.

    What do all of you think?

    Thanks.

    Frank
     
  2. tbakowsky

    tbakowsky F1 World Champ
    Consultant Professional Ferrari Technician

    Sep 18, 2002
    19,386
    The Cold North
    Full Name:
    Tom
    #2 tbakowsky, Apr 5, 2014
    Do you have an aftermarket radio in your 550?
     
  3. fatbillybob

    fatbillybob Two Time F1 World Champ
    Consultant Owner

    Aug 10, 2002
    26,406
    socal
    #3 fatbillybob, Apr 5, 2014
    How was this determined? Was the wiring diagram sought and fusebox actually taken out of car to backprobe? Is there any more to the story?
     
  4. FPFaeth

    FPFaeth Formula Junior

    Dec 3, 2009
    663
    NY
    Full Name:
    Frank Faeth
    #4 FPFaeth, Apr 6, 2014
    Hi,

    Thanks for the responses.

    1) The radio is original equipment.
    2) As for FBB's question, I really don't know the answer to your questions. I saw the technician probing the fuses and relays and him finding he had power and all. We also checked for moisture and corrosion and didn't find any. What do you suggest as next steps? You have a wealth of knowledge. Thanks.

    BTW, this all occurred after I retrieved the car from the shop. I had them do three things for me: change the coolant; repair the leather on the passenger airbag; and repair the leather trim on the rear shelf (vertical piece that mates up to the center mounted stop light). Could any of these have caused the problem?

    Regards,
    Frank
     
  5. fatbillybob

    fatbillybob Two Time F1 World Champ
    Consultant Owner

    Aug 10, 2002
    26,406
    socal
    #5 fatbillybob, Apr 6, 2014
    That's what I mean by is there more to the story. My first thought is that checking or moisture is a casual observance is a good thing because we know 550's can leak by the A piller. When you have problems we always look to the last thing done to see if there could be a possible source there. So the problem becomes partly wiring and partly routing, and partly how things work. For example how is the 3rd light wired relative to the tail lights. Can you short the 3rd light and kill the tail lights? Maybe depending on how its wired. If the 3rd light works independent of the tails then its not the problem. Same goes with the airbag cover nothing should have been disturbed but Ferrari wiring bundles are not clean. They are like a rats nest or a bowl of pasta. So it is pretty easy to pinch and damage wires just about anywhere unintentionally. Those issues aside it sure would be nice if there was another 550 around you could swap fuseboxes with as a test. There is no way I know of to test the fusebox while in the car. Even opening it and back probing wires is iffy because connections can still be intermittent and poor. That's why I rewired one of my 550 boxes and why SRI makes a fusebox repair solution. The 550 is generally the most reliable Ferrari out there but many 550's are running out there with 1 thing wrong often related to the fusebox.
     
  6. FPFaeth

    FPFaeth Formula Junior

    Dec 3, 2009
    663
    NY
    Full Name:
    Frank Faeth
    #6 FPFaeth, Apr 6, 2014
    Thanks, FBB. I will pass this info onto my repair shop technician. Appreciate your help. Frank
     

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