Twinkle Twinkle little light

The Ferrari 348 GTS has character—and sometimes a mind of its own. Especially when the pop-up headlights decide to give a charming twink rather than a smooth, seamless rise.

Our model exhibited exactly this behavior:

One headlight raised smoothly, while the other got stuck in a sort of “half-sleep” – or both stopped halfway up, as if they’d spontaneously changed their minds. Such problems are not uncommon with pop-up headlights. Typical causes include:

Worn-out motors – after years of use, they simply lack the power

Fickle electrical system – sometimes there’s a connection, sometimes there isn’t

Rusted or dry mechanics – when it scrapes instead of gliding.

We’ve already covered these points in detail in an older blog post; feel free to check it out:

In our particular case, however, the problem lay elsewhere: the relays had been swapped. This caused the headlight motors to receive incorrect or incomplete signals. The result: erratic movements, stopping halfway, or completely unpredictable behavior.

Once the relays were properly installed, the system worked as intended again.

But what exactly is a relay?

Many of our readers already know this, but for the others, we’d like to explain it. A relay’s main function is to separate control current from operating current to prevent sensitive switches from having to handle high currents, which would be neither efficient nor durable. Without a relay, in this specific case, the current driving the window motor would have to flow through half the car and through the steering column switch. The sliding contacts are not suitable for this and would quickly fail due to wear. With a relay, the steering column switch only turns the power on and off, which uses an electromagnet to establish the contact for the operating current, as you can see in the following video:

There are also different types of relays. Some are off when not activated, others are on when not activated, and there are some that supply power to one terminal when not activated and to the other when activated. Here’s what that looks like:

The headlight motor circuit uses different types of components, and if you mix them up, the car will start flashing its headlights.

To put it simply, there is a “switching relay” for both headlights. This relay sends power to one contact when the headlights are supposed to raise, and to the other contact when they are supposed to lower. These contacts are then connected to sliding contacts located in the headlight lift motors. When a command to raise or lower the headlights is received, the connection via the sliding contact is maintained only until the headlight has passed over the contact. The other end of each sliding contact is connected to a relay, which simply turns the headlight lift motors on and off.

To make things a bit more interesting, additional circuits are integrated that control how the system should respond when the parking lights or high beams are activated—but we won’t get into that, because now comes the commercial part:

Buy plenty of relays! We have some in our lineup that are electrically identical but feature a modern plastic housing, and others with beautiful, original metal housings—though these are used and tested: