Window doesn’t always go down while opening door

Hello everyone!


Just a month ago I bought a 1999 US-spec 550 Maranello. The car is just fantastic and thank to this community (and info I found here) I managed to fix many issues the car had.


But there’s one annoying issue I couldn’t fix and couldn’t find the solution.


The passenger window doesn’t always go down a little when I open the door. Sometimes it does, sometimes it doesn’t. No matter which handle I pull (inner or outer), or if the car is started or not. Just 50/50. If I reboot (calibrate) the ECU by pushing the window button up and down for a while, it works fine until I lock and unlock the car again. Then again 3 times yes 5 times no.. Checked all the wires, the microswitch, everything looks fine. Seems like ECU fault that doesn’t depend on anything else but it’s own brain. At driver’s side all works just fine.


Do I have to replace the windows ECU?

Or should I first look somewhere else?

 

It sounds likely, but considering the cost of a new ECU, I would do everything I could to check everything thoroughly.

e.g. Did you make sure the signals from the inner and outer door microswitches were always present at the ECU. I would make sure you get an earth (ground) at pin C5 on the ECU every time you operate the handles (to exclude an intermittent wiring problem from the door to the ECU).

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Can you keep the handle pulled and shake the wiring and door to see if you lose the earth

 

Wiring diagram here:

550_Window_Control

 

Thank you! I will check. By the way could you tell me where exactly the ECU is located?

 

Congrats on you 550!! Is it so that it is possible to calibrate the windows? Mine always go about 2 cm down when I pull the handle even if the battery have been taken off. On my Jag, the windows goes about 5 inches down after battery cut off. But when i calibrate by holding it for about two seconds at top and bottom position, they become calibrate and then they only lower about one cm. when i pull the handle. It like a bit better than the Ferrari which opens up much more.... Please explain if you know! Thanks, Erik.

 

пожалуйста

I believe it is located above the relay panel in the passenger footwell.

https://www.scuderiacarparts.com/part-finder/ferrari/550575/oe/26/1851/33951

Item 1. (P/N 166850 for Euro cars)

 

It looks like the earth is inside the ECU. You can check the whole handle microswitch circuit by checking the continuity (resistance) between pins C5 and B15 (blue/black wire) when the handles are moved to the open position.

 

Looking at other forum posts, I see that airconditioning condensation in the passenger footwell can cause problems with the ECU:

https://www.ferrarichat.com/forum/threads/access-central-condensate-outlet-tube-a-c.453362/#post-143224149

Check the pins/sockets for corrosion.

 

Thank you!!! Very helpful information!

I’ll check all this and return