12 volt power to window motors schematic | FerrariChat

12 volt power to window motors schematic

Discussion in 'Mondial' started by Alden, Aug 31, 2025.

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  1. Alden

    Alden F1 Rookie
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    Apr 25, 2010
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  2. DanielGA

    DanielGA Karting

    Mar 19, 2018
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    Daniel A.
    My passenger window is slow (Mondial); I opened up the gears and they are fine. Instead, it seems I get only 7.5v to raise the windows and 9v to lower them. I suppose these wires to go window switch and to fuse box, all of which I have cleaned (fusebox) and changed (window switch).

    I already have the window accelerators but that only "improves" the connection to ground.

    Oh well.

    Maybe Alden's option is best. However, then I have to route 12v to inside the door panel.

    1. Any recommendation of how to get to the wire bundle that goes to the door...before I rip everything apart, I was wondering if some knowledgable soul can shed some light my way...

    2. If my signal from window switch is only 7.5 and 9v is that enough to "activate" the relays?
     
  3. afterburner

    afterburner F1 Rookie
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    Yes
     
  4. Alden

    Alden F1 Rookie
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    When I did the simple relay mod without bringing power to the doors, I went from around 7.0 to 11.7 volts just by improving the ground.
    From my post:
    "Voltage to the motors before the mod
    6.8 to 7.8
    After average voltage to the motors was 11.7
    Window up before mod 4.9 seconds
    After mod 2.3 seconds
    Window down before mod 3.0 seconds
    After mod 2.0 seconds
    So this is definitely worth it."

    Alden
     
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  5. DanielGA

    DanielGA Karting

    Mar 19, 2018
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    Thanks! The window accelerators I already installed improved the ground but still the voltage is 7.5 or 9. I did run a wire directly to the battery negative and used one of the wires that normally connects directly to the motors and I still get 7.5 or 9v, so the positive line has some extra resistance on it somewhere...I have not analyzed so precisely the driver's side door...it works quite well. I ordered the relays and will do that for the passenger side, at least...just got to figure out how to nicely route fresh power lines to the passenger door.
     
  6. afterburner

    afterburner F1 Rookie
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    There is enough space inside the rubber bellows for an additional wire, but on the driver's side it's tight. It will make a huge difference. Just do a test with an external wire from the battery to the motor to see how they work with full power.
     
  7. Alden

    Alden F1 Rookie
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    Did you thoroughly clean and deoxit the switches?
    Alden
     
  8. Alden

    Alden F1 Rookie
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    I don't really understand what you did here, you can't run a ground directly from the battery to the window wires without the relays, which relay kit did you install? With the kit that requires 12 volts from the battery you have to run a single positive 12 volt line to each relay set in each door not a negative??
    Alden
     
  9. DanielGA

    DanielGA Karting

    Mar 19, 2018
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    Switches are brand new.

    I previously installed the "window accelerators" from Ricambia or AWItalian (can't remember ). Those boxes enable using a new ground wire, say to the door frame but do not address the conductivity of the +V from the two wires that somehow come from the switches.

    Now, instead I want to install the two relay circuit, which you posted, in my passenger door (maybe drivers side but that side works good). I just ran a new wire, painfully, through the door loom. Relays and fuses arrive today; maybe have it working again by weekend (have other todos :))
     
  10. DanielGA

    DanielGA Karting

    Mar 19, 2018
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    (the above reference to running a negative wire was not a permanent installation...I just temporarily placed a wire on the battery negative and the other side used as negative for a window motor test...it did not change the voltage...this means my door frame grounding is just as good)
     
  11. Alden

    Alden F1 Rookie
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    Just to clarify, both mods are two relay mods, the first one below does not require a 12 volt wire from the battery, it only improves the ground because it grounds direct to the door and doesn't run power back thru the switch.
    The second mod also uses 2 relays but requires a new 12 volt source power wire to be run from the battery.
    Also, your switches are probably unused NOS, not really brand new, so apply Deoxit liberally anyway, it won't hurt anything.
    Alden
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  12. DanielGA

    DanielGA Karting

    Mar 19, 2018
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    Many thanks! The second circuit (with new 12v wire) is implemented. Works great! Not quite like a "a modern car" -- but good. Now the previously seemingly ok drivers side is comparatively a bit slower, but oh well ... both quite usable.

    Now on to other funner parts...
     
  13. UsernameBob

    UsernameBob Karting

    Jan 21, 2025
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    Rob Dyer
    I have the V40 window motors all ready to modify, but my original rear window motors work. I do wonder if I should clean them all and do some of the trickery above rather than go to the Volvo motors. Presumably the rear windows have the same power supply issue as the fronts?
     
  14. Alden

    Alden F1 Rookie
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    Same same power supply issues since it all runs through the switches, it's up to you which mod you do, if you want to go to the trouble of running a 12-volt source directly to the relays and the doors, I think that is the ultimate solution, but I would try cleaning and deoxit the switches, and cleaning and lubing all the mechanism first.
    Alden
     

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