Rear Fog Lights not Working | FerrariChat

Rear Fog Lights not Working

Discussion in 'Mondial' started by John Mc, Nov 4, 2020.

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  1. John Mc

    John Mc Rookie

    Feb 23, 2019
    27
    Herts, UK
    I was wondering if anyone could offer some advice?

    I took my QV for an MOT (UK) and it failed on a couple of small items, one of which was the rear fog lights are not operational.

    We have checked the bulbs - all OK; the fuses - again all OK; there is power going to the lights, so was wondering if possibly a relay? There is no warning light indicating that the lights are not working, so that is why we are thinking relay.

    Sorry, possibly an easy fix, but a little frustrating and I do not want to order new switches if not needed.

    Thanks.

    John
     
  2. mike32

    mike32 F1 Veteran

    May 13, 2016
    5,835
    Isle of man- uk
    Looking at the wiring diagram the bulb holder has 1 supply wire, so the fitting must have a wire to the bodywork. Put a volt meter between the bulb connection in the bottom of the fitting and a known earth on the chassis. If u get 12 volts then you need to check the earth connections.
    Book does not show separate fuse or relay for rear fogs, as they supply other light. Fuses 15/16/17 cover these.
    See if you have volts at the fitting, other wise go back to the on off button on the dash
     
  3. John Mc

    John Mc Rookie

    Feb 23, 2019
    27
    Herts, UK
    Thanks for the advice. I shall have a go at that later.
     
  4. mike32

    mike32 F1 Veteran

    May 13, 2016
    5,835
    Isle of man- uk
    One fitting will have the supply in, plus a supply wire taken off it to supply the other light.
     
  5. theunissenguido

    theunissenguido Formula 3
    Owner Silver Subscribed

    Jan 21, 2004
    2,372
    Argent/Brasil
    Full Name:
    Guido
    I believe, your other lights have to work first in order that the fog light work. Turn your normal lights on and try fog light.
     
  6. ONSilver

    ONSilver Karting

    May 26, 2008
    183
    Oakville, Ontario
    On my 1987 3.2 Swiss spec cabriolet, the rear foglights only work when the headlights are on.
     
  7. moysiuan

    moysiuan F1 Rookie
    Silver Subscribed

    Nov 1, 2005
    3,645
    Canada
    Same with my Swiss mondial.
     
  8. mike32

    mike32 F1 Veteran

    May 13, 2016
    5,835
    Isle of man- uk
    Any joy fixing them ?
     
  9. John Mc

    John Mc Rookie

    Feb 23, 2019
    27
    Herts, UK
    Hi Mike.
    Thanks for following up.
    Still no joy so I have ordered a relay to replace the existing. Spoke to a mechanic locally who looks after a number of classic cars including Ferraris and he said that it is worth doing the easy things first. On order and arriving in a couple of days.
    Will let you know how I get on.
     
  10. John Mc

    John Mc Rookie

    Feb 23, 2019
    27
    Herts, UK
    The headlights work as they should and so do the other lights, so will try the relay and see how we get on
     
  11. mike32

    mike32 F1 Veteran

    May 13, 2016
    5,835
    Isle of man- uk
    Do not think that will work as no specific rear fog light relay. To the LH side of the instrument panel is connector block C5. Look for an Orange wire going through it, live supply to rear fogs.
    Switches for heated rear window, front bonnet open, front fogs, engine bonnet, rear fogs, boot lid. All these switches are wired to one terminal strip so if others working you need to check all the connections . Rear fog looks to be connected to No 1 or 3, will be the orange wire. Looking at the fog switch, it might be a relay in itself, are they available to buy. You need to prove the switch itself.
     
  12. mike32

    mike32 F1 Veteran

    May 13, 2016
    5,835
    Isle of man- uk
    I looked on the eurospares diagrams and the switch is the bottom left in a group of 6. Pt no 121609 @ £158+ vat if needed.
     
  13. Mondi Cab

    Mondi Cab Karting

    Oct 9, 2019
    153
    EU
    Full Name:
    J.Schulz
    Hello Mike 32,

    Since you seem to have the partlist at hand, might you have a look for the FRONT foggies switch too?

    I drove with the parking lights + front foggies on in order to maintain the headlights flipped down, but all of a sudden the front fogs started flickering and then went off - permanently. The switch feels dead ever since when you cycle it.
    Must be burnt.

    Thanks in advance,

    Mondi Cab
     
  14. mike32

    mike32 F1 Veteran

    May 13, 2016
    5,835
    Isle of man- uk
    Look on eurospares web site, plate 122 on 87 mondial. Looks like front fog is left hand side switch in the middle. Comes up as item 5. Pt no 121607. @£250 in stock. Note some of these switches marked as not for US ? No idea why
    Looking at the wiring diagram it shows a coil in the switch so i think it is a self contained switch/ relay.
    There are no specific relay for front and rear fogs in the fuse box.
     

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