348 Another headlight issue...

Strange. I assume you mean that the headlights pop up and down with the ignition off and the headlight switch on, or does it happen with the headlight switch off and you have to use the battery cutoff switch to stop this happening?

I've been looking at the circuit for the last hour and not making much headway. I'm wondering if a shorted diode in one of the headlamp motors could cause this problem. Unless someone comes up with an alternative, easier faultfinding path, could you disconnect the two plugs on one headlight motor to see if it restores operation to the other headlight lifting system? If not, try disconnecting the plugs on the other headlight motor (reconnect the other one).

 

Dan, when the headlights pop up, are they illuminated?

Why do you ask? Have you removed the bulbs?

 

Before you start pulling plugs off the motors, in theory, you could check for a shorted diode by pulling the control relay ("a") in the forward luggage compartment and, with the battery off, use a multimeter to check for continuity between contacts 87 and 87a of the relay socket (reverse the ohmmeter leads if you get an open circuit). If you get an open circuit in both directions, the diodes should be ok.

If you do get continuity (or a small resistance) with this check, it won't tell you which of the headlight pod diodes are faulty, so you'll have to disconnect both "stepped" connectors on one side of the car.

 

Further thoughts...

The headlight lift relay (a) or the "control headlight relay" as you call it, puts out (battery) power to the headlight pod gearboxes irrespective of whether the relay is energised or not. The AC relay you substituted would only put out power with the relay energised. This suggests that the stalk switch input seems to be ok (as you surmised) as the substitute relay's state was altered by the stalk switch.

As you didn't replace the headlight lift relay (a) with the same type, why not try swapping the relay with the same type if there are any (Does the daytime flasher relay "g" have the same part number?). We don't yet know if this relay is part of the problem. There may be multiple factors.

Here's the diagram:

F348 Headlight wiring diagram (sans column switch shown)

You didn't state the part number of the "control headlight relay". Does it have the same part number as the L&R lifting relays?

(EDIT) I'm starting to rethink my earlier theory about shorted diodes, but taking one headlight motor/gearbox out of the equation by disconnecting the two plugs on one side still sounds like a good idea. How easy are these plugs to get on the F348 (hopefully easier than the F355).

 

I do not remember how the actual two 2-pin (stepped) connectors for each lift motor look but, according to the diagram, they seem to be the same (are they different colour?). If the connectors are swapped over between the two of them at each motor (connected wrongly) this will bring permanent 12V to each motor so it will continuously run (with the ignition and the light switch off). Worth double checking whether the 2-pin connectors are connected correctly.

 

I recall the plugs are black and white on the F355. Not sure about the F348.

If the plugs are the same colour, comparing wire colours on either sides of the plugs might offer a clue. On the F355, the green-black wire has a green-black wire counterpart. The rest have mismatching colours however.

 

Do not swap them if you find that they are connected with the colours matching. On the other hand, they might be covered in dust/dirt so make sure you can actually see their colours. Here's a pic of a 348 motor showing that one connector is black and the other white (well, dirty white).

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Hard to tell for sure, but the colours on the motor look similar to the 355's, so I'll mark the 348 diagram accordingly.

Headlight Wiring Diagram

At the control relay you should have:

pin 30 : hot battery power
pin 85 : ignition power (if the ignition is on)
pin 86 : earth if the light switch is on
pin 87 : Probably no volts, but I'm not sure about the resistance anymore... It looks like it depends on where the gearbox is in its cycle. It might show headlight relay coil resistance. I'm wondering if the ohmmeter voltage will trigger the headlight relays.
pin 87a: ditto

 

For clarity they did not work one day then stop the next. I assume you got the car and they never worked or you did work on it and reversed the connections?

 

Hi Guys,

I finally have my car at home, got it on my birthday!!. I just realized that one of the bulbs (the one next to the blinker) on the driver’s side is not working. I would like to get a new bulb but after reading several posts/diagrams and my348.com I don’t know what bulb I need. Can you help me with this?.
I have added a picture and highlighted the area in yellow.


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Anyone?.. I am completely lost.. maybe the same as the rear parking lights (manual description name). R5W bulbs or 1156@5w?. In the manual it calls it a “front parking light”.

 

There should be a spare in your toolkit so just take the light unit out and install your toolkit one then just go buy a replacement for your toolkit

 

The Workshop Manual identifies these lights as "Front parking lights", with 12 volt spherical 5W lamps (same as the licence plate lights). Strange. I would have expected the licence plate lights to be smaller.

Are there no markings on the old lamps/bulbs?

 

Did you try to google "Ferrari 348 front parking light bulb"? Alternatively, remove the light assembly and see what's in there.

 

I don’t have it, that is why I don’t know what to do. I will probably have to open and check what bulb is inside.

 

yes, I tried but no luck. It is easy to find about the rears but the front is not that easy.

 

Just remembered I have my original spare driving light in the garage so popped the cover and took some photos - hope it helps!

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As mentioned above you should have a spare of each in your toolkit tray - look in there to get the exact wattage etc and then either buty in advance or use them and replace - if I were you I would replace all teh bulbs whilst you have the unit out

 

Wow!, If I am not wrong it is the one that has the yellow wire. It looks exactly like the ones on the rear (r5w or 1156). We just need to find the right W.
Thanks a lot.

I recently bought a tool kit super new but it is from a different car, not a 348. I am afraid bulbs might not be the same.

 

My google search found this site: https://alleuro.com/Models/Ferrari/348-Spider/Electrical,-Lighting-and-Body/Lighting-_-Exterior/Parking-Light-Bulb?

Search of this forum resulted in this very useful thread: https://www.ferrarichat.com/forum/threads/update-reference-info-for-348-bulbs.503412/

 

Right I found that too but I am confused because the first link shows a 8w bulb and the ine in the manual says 5w. That is why I have the feeling that the ones for the rear are valid for the front too.