Ferrari Mailing List: Re: Keeping busy with Ferrari stuff

[Anthony Bauco (tbauco]

Send pics of the other sides of the two PCBs.  It looks like two pins power the PCB and two pins power the bulb.  If the black wire in the wiring harness has the lowest resistance to ground then that is ground.  Hard to say if it is ground for the bulb or the PCB without the additional pics.  If your battery is connected, you should read a voltage to ground on one of the pins, even with the key out.  That would be power for the PCB.  Read voltage on all four pins with the key OFF and the key ON.  With the key in the ON position, there should be voltage on another pin.  That would be for the bulb. My guess is that you will see voltage on two of the other pins and it will rise on one when the headlights are turned on.  Often they will increase voltage on the return side to dim the bulb.

On Wed, Jan 19, 2022, 11:33 PM Peter Rychel <dino308gt4 [at] hotmail.com> wrote:

Anthony wrote:

 

“Do you have the wiring diagram for the car and a picture of the connector in the clock.  It would be easy to deduce it from there.  If not, we could ohm things out and do process of elimination.

 

Charles wrote:

 

"Correct. This is his website:

 

http://www.ferrari308gtbi.com/Wiring308.php

 

If memory serves, I don’t think anyone has Mondial diagrams. I think they are a 90% match to the equivalent 3-series car, so Paul used to tell people that with a few exceptions, the same year 308 diagram was the way to go.”

 

 

 

 

Thanks guys, but the T was quite the departure from any previous model and differs a lot from the 308/328 series (I’ve got most of them, including Paul’s on my desktop).

 

I have the wiring diagram for the 3.2 Mondial (it came with a bunch of manuals I got a long time ago, before I got my Cab) and it doesn’t come close to matching.

 

There’s only four wires and I checked continuity. Keep in mind, the battery is disconnected at the shut-off switch (Batt neg pole). All four wires show levels of resistance, the black wire being the least – my guess it’s ground. I know one wire must supply continuous power so the clock can keep memory. Another wire must be the one that light’s up the bulb which would come on when the ignition is turned on. The other wire may be a dimmer function (?), although when I turned the dimmer knob, nothing changed. At least with the key in the off position…

 

I’ll take a closer look at the 3.2 drawing which also has four wires, but all of them are different colors. Makes sense because the clocks are made by different manufacturers. The earlier cars may have been made by Veglia, this one is marked Jaeger.

 

Peter