Electric problem. 348tb

Although it may not matter here, but there are a few variations during the model run, what year is your tb?

 

No fuse for the windshield washer pump (107) but it shares the same ground point as the air horns. Following the wiring diagram, it's circuit goes through the front fuse box (26) and on to the Switch for windscreen wiper and washer (35).

Still looking for the rear dome light (diagram references "Front Dome Light")...

 

BTW, if you open one of the doors, the interior dome light should come on, along with the "Open door marker light".

Footrest Fusebox - Fuse #3 (A15): Daytime Flasher Lighter - Interior Light - Power socket

 

The washer pump uses Fuse 5 in the footwell, but, that also powers the brake lights, windscreen wiper, glovebox light and electric mirrors.
door mirrors. I think Fuse 3 is for the overhead light and door marker (open) lights and may even have something to do with the daylight flashers.

Probably two unrelated problems.

(EDIT: Sorry, cross-posted with Wade)

 

Washer wiring diagram

Dome light wiring diagram

 

Yeah, my diagrams are older. Fuse 5 in the footwell shows: Window wiper - Stop lights - Glove box lighting - Door mirrors

But looking at your diagram (which is awesome btw) gives me more insight.

 

There is probably not much difference between different cars in respect to the systems we area talking about. Just let us know if the other items attached to their respective fuses are operating. If it's not a fuse issue, we have to look at the wiring for the light and the windscreen washer. I assume you've replaced the overhead light bulb and listened for washer motor operation? Of course, the ignition must be on for washer operation.

When you say the washer doesn't work, do you mean just the water spray or the wiper also (when you use the washer)? If the wiper works when you try to use the washer, it means that the steering column switch is ok. In this case, you have to get access to your washer motor electrical plug to check for voltage and a good earth.

 

Not sure, but it's the same earth as:

Right hand headlight and lift motor
Airconditioning condensor fan motor

Are any of these other items showing unusual behaviour?

 

IIRC, there are ground points in the front trunk, behind each of the headlamps. You'd need to remove the fitted carpet to access them. On my LHD car, the washer pump & air horns are probably grounded behind the right side headlamp.

 

A bit vague, but there is an earth symbol shown in this Ricambi diagram

https://www.ricambiamerica.com/car-diagrams/ferrari/v6-v8/348-group/348-1989-1992/electrical-system-valid-for-usa.html

 

Zip tie?

Glad to hear you got your washer problem sorted, Marc

Perhaps it's better to start a new message thread for your new problem (to avoid confusion).

Cheers