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355 fuse for headlight motors

Discussion in 'Technical Q&A' started by Barnone 308, Apr 8, 2011.

  1. Barnone 308

    Barnone 308 Formula Junior

    Mar 22, 2004
    430
    canada
    quick question. went to start my 1998 355 today, first start after the long winter. The lights went up an inch and stopped. The lights are on, but the motors never turned the lights over. Any advice. I think it would be the fuses.
     
  2. Paul_308

    Paul_308 Formula 3

    Mar 12, 2004
    2,335
    #2 Paul_308, Apr 10, 2011
    Last edited by a moderator: Sep 7, 2017
    There are electrical contacts in the light pods and contacts in the relays which control them. If you do not find a blown fuse, replace the 3 motor lift relays.
    Pic below is from the 355 Workshop Manual III page L27 showing trunk mounted 7.5A fuse and Bosch 0332209159 relay locations. That relay is still readily available at around $12.
    Image Unavailable, Please Login
     
  3. f355spider

    f355spider F1 World Champ
    Rossa Subscribed Owner

    May 29, 2001
    17,026
    USA
    Full Name:
    Hugh G. Rection
    Fuses are relays are located in the front trunk. Right side, under a small cover above the right front wheel. Two nuts to remove the cover, then there are two more nuts that secure a plastic cover and vinyl dust shield. The fuses are 7.5amp. It is not uncommon for the cars to occasionally blow them on a cold winter day...as the motors age, and grease or lube inside them gets old and hard. .
     
  4. Barnone 308

    Barnone 308 Formula Junior

    Mar 22, 2004
    430
    canada
    Thanks guys

    A mechanic told me that I need to check the voltage is draws because at times your motor might be slowing down, and in need of replacement.
     
  5. f355spider

    f355spider F1 World Champ
    Rossa Subscribed Owner

    May 29, 2001
    17,026
    USA
    Full Name:
    Hugh G. Rection
    #5 f355spider, Apr 12, 2011
    Last edited: Apr 12, 2011
    Have you confirmed you have a blown fuse? My right side would blow a couple times each winter and it was annoying, so I put a 10amp in there and that cured it. Not the most elegant fix, but works until I can tear into it....going on a 2+ years now.
     
  6. Barnone 308

    Barnone 308 Formula Junior

    Mar 22, 2004
    430
    canada
    I think thats what I will do for now. I bought a package of fuses. I will keep replacing them untill they feel like not blowing anymore. I have replaced it twice now. So hopefully it should be ok for now.
     
  7. Jeff Pintler

    Jeff Pintler Formula Junior
    Silver Subscribed

    Jul 20, 2005
    528
    Richland
    Full Name:
    Jeff Pintler
    Before you throw money at motors, take some time and measure the current draw. I have found that if the fuses blow at the top or bottom limits, it means the rubber bumper stops have aged and are hard. The motor can draw exceed 300% and blow the fuse. The stops are easy to adjust. The current draw can be measured using a digital volt meter with a peak hold function and just touching the meter probes on the metal nubbins on the top of a blown fuse. Find a schematic and remember that it is very unlikely that both motors go bad. FWIW

    Jeff Pintler
    89 348tb, 86tr, 99 360 3-pedal
     
  8. Paul_308

    Paul_308 Formula 3

    Mar 12, 2004
    2,335
    Change to 10A fuses of better yet, self-resetting 10A circuit breakers.
     
  9. ThatFlyGuy

    ThatFlyGuy Rookie

    Jul 10, 2020
    38
    Toronto, Canada
    Full Name:
    Cy Sawyer
    New comment to an old thread. I have this exact issue. I have blown 4 fused now in as many days for the LH headlight. One of them popped as I pushed it into place.

    My mechanic said the motor tested okay. Not sure what to do here. I will replace the relay as mentioned above, if not I will attempt to measure the draw, however, I am not too mechanically inclined lol.
     
  10. Qavion

    Qavion F1 Rookie

    Feb 20, 2015
    3,672
    Sydney
    Full Name:
    Ian Riddell
    It will be difficult to make a diagnosis depending on how he/she checked the motor/gearbox. On first impressions, however, it does sound like there is some kind of mechanical resistance which is causing a strain on the motor electrical circuit.

    You could disconnect the battery and use the knob on top of the motor to wind the headlight up and down to see if there is any unusual resistance. The motor only runs in one direction (for both up and down). I'm not sure if it's harmful to wind the motor in the opposite direction to normal (it would depend on the design of the electrical contacts inside the gearbox). There are no warnings in the manual, so I assume it's safe. Note that you will have to use a lot of turns on the knob to get the headlight pod to move (due to gear ratio).
    Internally there are some plastic gears which disintegrate over time. They may be jamming up the gearbox.

    You could try lubricating the linkages from the gearbox to the pod (and make sure the linkages are not hitting anything as you wind the knob). The linkage length is critical, so don't disassemble anything without noting the positions of nuts, etc.

    There are a number of electrical components inside/on the motor-gearbox assembly which can break, but if you are blowing a left motor fuse, that narrows down the possibilities. I would try swapping the LH and RH motor relays in the forward luggage compartment to eliminate a relay problem. Don't confuse them with the headlight motor control relay. Use your Owner's Handbook to identify the correct relays.

    When you restore battery power, the headlight pods may cycle up and down, so keep your fingers clear.

    If you're not mechanically (or electrically) minded, and the winding tests don't reveal anything jamming/sticking, then it may be best just to have motor replaced for further evaluation.
     
  11. ThatFlyGuy

    ThatFlyGuy Rookie

    Jul 10, 2020
    38
    Toronto, Canada
    Full Name:
    Cy Sawyer
    Excellent information! Thank you. I can try swapping the LH and RH motor relays to see if the issue follows to the other side or not. The rest would be for my mechanic.

    I JUST replaced the plastic torque pins in my Lotus Esprit like a month ago lol. That was easy though and cheap at $4.25 for the set :p
     
  12. Qavion

    Qavion F1 Rookie

    Feb 20, 2015
    3,672
    Sydney
    Full Name:
    Ian Riddell
    Been there, done that ... My previous car was an '89 SE :D
     
    ThatFlyGuy likes this.
  13. ThatFlyGuy

    ThatFlyGuy Rookie

    Jul 10, 2020
    38
    Toronto, Canada
    Full Name:
    Cy Sawyer
    Good thing for it being a cheap GM part lol.

    The Ferrari headlight system seems so much more complicated than those to me.
     
    Qavion likes this.

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