Dash Lights failed - 1987 US 3.2 coupe | FerrariChat

Dash Lights failed - 1987 US 3.2 coupe

Discussion in 'Mondial' started by djs308, Apr 6, 2025.

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  1. djs308

    djs308 Formula 3
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    Sep 2, 2002
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    Long Island, NY
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    David S.
    After not driving it for a few weeks, I took the car out today. Drove fine, nothing amiss. At nightfall, I went for another drive. Headlights, Brake lights and interior Warning lights are all working fine. Parking lights (side markers) are working fine. But Dash lights (Speedo, Tach, Fuel, etc.) are NOT working. Hmmm...

    Yes, the car has had intermittent electric gremlins before, but those were addressed. Nothing recently has occurred, outside of the clock resetting itself at random times. But the clock is working fine today!

    My manual says dash lights should be fuse #21. I pulled it and the fuse appears ok, though its plastic housing does have a hairline crack. Possible oxidation on the exposed metal, but looks to be minimal. Clearly, it's an easy thing to change, but I'm not convinced this is the source of the issue.

    Other threads I searched linked dash lights with side markers. But my side markers are lighting up.

    I'm NOT a DIY guy and don't comprehend wiring diagrams very well, but I'd like to try and narrow things down I can check before I bring it in to get it diagnosed. Any suggestions on what else to look for?
     
  2. Alden

    Alden F1 Rookie
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    Apr 25, 2010
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    I don't have the wiring diagram with me right now, but last time that happened to my car several years ago I did a simple refresh of the fuse/relay box, cleaned and replaced all fuses and relays and sprayed everything with Deoxit . Cost was about $300 for parts and a few hours of my time. Put it back together and everything came back fine, I'm sure there's a a wire or two on one of the white connectors is probably causing the problem but it also could be the your fuse board is delaminating if you have the original, I have an upgraded GT parts board in my car.
    Alden
     
  3. djs308

    djs308 Formula 3
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    David S.
    My fuse box was checked out a couple years ago and deemed still to be "ok". The shop that had the car stripped out a bunch of wiring from an ancient Clifford alarm and they cleaned up that mess. Since then, the only weirdness has been my clock intermittently conking out. Everything else has been behaving—until this new issue with the dash lights. Still odd that this would happen after simply sitting for a few weeks.
    I just ordered a whole set of new fuses so I will certainly give that a try first as maybe that's all it might need, as you suggested.
    Thanks.
     
  4. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    Jan 11, 2001
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    30°30'40" N 97°35'41" W (Texas)
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    Have you given the dash light rheostat dimmer knob about a zillion rotations back-and-forth to try to "wipe" the contact between the brush and windings into health? ;)
     
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  5. djs308

    djs308 Formula 3
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    Ah, No I have not! That's a very good (and easy) thing to check. Will give that a shot. Thank you.
     
  6. Alden

    Alden F1 Rookie
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    Nice, Steve! Also: Operation is not intuitive: Counterclockwise is brighter, clockwise is dimmer, believe it or not!
    Alden
     
  7. djs308

    djs308 Formula 3
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    UPDATE:

    Issue has been successfully resolved!
    Steve's @Steve Magnusson suggestion was exactly what I needed. Sure enough, a firm twist of the knob got the Dash Lights back on. Thank you, Sir!

    And thank you's go to those who offered assistance on and off line @Alden etc.

    Whew! I'm just glad it was indeed a relatively simple "fix".
     
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  8. Alden

    Alden F1 Rookie
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    Thanks for the update and reply, so many people come here for solutions and we never hear whether or not they got the problem fixed! If you post a problem fixed it helps other folks if they search for the same topic.
    Alden
     
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  9. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
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    Jan 11, 2001
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    So was the dimmer knob just set to minimum/off, or did it need some "wiping" to improve the contact?
     
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  10. djs308

    djs308 Formula 3
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    Yep, it was in the full "OFF" position. Which means I'm a total dunce. :oops:
    But I did cycle the knob a few times just to be certain it wasn't an oxidation issue anyway. No clue how it got into the Off position. Maybe I did it accidentally when I was trying to reset the Trip computer and got the wrong knob initially?

    Anyway, I've actually had that problem (Oxidation) with my battery cut off switch failing—that was a number of years ago. Cycling that switch DID correct the issue.
     
  11. Alden

    Alden F1 Rookie
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    Deoxit is your friend. I put that *hit on everything.
    Alden
     
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