Everything you need to know about Mondial trunk buttons!

There have been a few threads about those buttons on the Mondial dash that operate the solenoids on the bonnet, engine cover and trunk. They look like just a button on the dash, but inside are electronics and when they go flaky, can they be fixed?

Well, here is a thread about them.

I had the trunk button go south on mine such that the trunk wouldn't open. Contact cleaner, which has solved so many electrical problems on my Fcars in the past, didn't fix it. So what to do next?

First, you start by removing the switch from the dash. This is easy. Step one, gently pry the bezel from around the Speedo with something that won't mangle the plastic. I like to use a plastic putty knife for this application. A credit card works too.
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Next you remove the four screws holding the speedo itself in the instrument pod. There is one in each corner.
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Now the speedo comes out easily and that also allows the little rack full of buttons to the left to come out. Be gentle with the wires as the back of the buttons have tabs that can break and there are 4 wires on each button.
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Each "button" (actually a little electronic box) has 4 terminals. Obviously more than just a simple switch.

•One for 12 V, always active regardless of key position.
•One for ground.
•One for 12 V from the instrument lighting circuit to run the little LED lights in it.
•One to send 12 v to the solenoid (trunk, engine cover or bonnet) when the button is pushed.

The schematic for what is actually inside the little rectangular box is below. Don't ask how I got this schematic. It's top secret. Ferrari would send a hit man if they knew where I got this information. (I actually took one apart, and believe me when I tell you, this is not for the faint of heart. I do not consider these rebuildable by most people. They have to be partially "destroyed" to disassemble as they can't come apart without removing the riveted connectors first.)

As you can see from the schematic, it is a simple transistor driving a small relay, which then switches the current for the solenoid. Why do it this way? The switch is a small delicate part and if the entire load of the solenoid was being switched directly by this little switch, the constant arcing would quickly destroy the switch contacts. So they use a relay. Not sure why they need to use a transistor though. I would think that the momentary switch directly running the coil on the relay would be fine, but the transistor isolates the switch even more, allowing it to only deal with mere milliamperes of current, so it should last a good long time. Should. I mean, it's a Ferrari so lets not expect too much.

The two LEDs are just backlighting for the button. See Ferrari is hip, they were using LED lighting long before it was cool.
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OK, last picture. What the guts actually look like.

And that's it...more then you ever needed to know about those mysterious little contraptions!

Birdman
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They can definitely be repaired, but it's not easy!