355 97 won’t switch off!?

Hi Josh, sounds like your new alternator is back feeding the power and keeping things on. Is the Alternator the same as the old one? I have not gone over my alternator but it should have a diode in there to stop back feeding. I found this on YouTube about checking the diode

 

Which lights? Instrument lights, exterior lights, warning lights.... ?

To make sure your ignition lock hasn't shorted out, you could try disconnecting the 8 pin plug at the base of the steering column to see if that kills power. It should have some big red, blue, white and other coloured wires on it.

 

Ah, ok. Can't say I've heard of this before, but I suppose there could be a wiring problem in the steering column (as the ignition and stalk switch harnesses run in the same general area).

 

Just to eliminate one possible cause - did you install a starter relay?

 

Good news, but no start and "abs ignition light" sound like pretty big gremlins. Do you mean the ABS or BRAKE warning light? Do you mean no (test) light on attempted start? Or a light on start?

Some F355's come with a starter relay as standard. May depend on year and region.

Do you have Teves ABS?

Here's the ABS wiring diagram showing the start relay and its link to the BRAKE [(!)] light test and the ABS pump cutout relay:

Fig4_Teves_ABS_System_5.2

Depending on the actual symptoms, the ignition lock may still be faulty (i.e. in the start position).

 

The ABS (pump) is powered with the key in position "I" (or what you might call "accessory"), until the pump gets up to the correct pressure (then the light should go out). If there are no other lights in the other positions, then it sounds like position II (ON) and START are still broken. Something is definitely cooked

If you think the lock or the column wiring is fried, you could disconnect the ignition lock at the 8 pin plug and try jumping the red wires and blue wires on the plug (not the lock side of the plug) to see if some of the other dash lights illuminate. Don't jumper the red wires to the white (or white/black as applicable) wires or the starter may engage. The red wire is hot battery power (so be careful). You may want to install a momentary switch in the jumper wire so that you don't get a spark when you hook up the wires.

 

Unplug the round connector at the alternator. If the car shuts down as normal..then you have the typical melted harness issue the 355 was well known for. Don't over think this.

 

Which harness melts, Tom? Ignition? Alternator?

 

Alternator.. unplug the round connector at the altermator. If its shorted..it will back feed and keep the car running even with the key off and out of the ignition.

 

Thanks. I think the OP did already find that the ignition harness had melted...

Finding out what else has been damaged could be tricky and what caused the problem in the first place.

 

The red and blue wire bridge was just to see if more lights illuminated on the dash (engine not running, with the 8 (or is it 6?) pin plug disconnected from the ignition switch i.e. to take the ignition switch taken out of the equation). Is this what you did? If you bridged these wires with the ignition lock plugged in, you wouldn't have been able to switch off the engine.

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How did you get the car to start? You said you had melted wiring in the steering column. Did you fix this already? I assume now because you started the car, that the start contact of the ignition lock is ok.

It's going to be difficult to explain to you how to check the wiring if you're not familiar with what we are talking about, but here's the wiring diagram for the F355 5.2 (gated) which might help.

Fig11a_1997_5.2_Injection_System_Ignition

(Best viewed on an iPad or similar device so you can magnify/scroll the image easily)

If Tom is referring to the harness going to the alternator "00206" (and not the alternator internal wiring which has melted), I guess you could individually check the continuity of the wiring from the alternator plug to the next available disconnect points. In some cases, it will be plug "41019" (just behind the rear left hand shock absorber), in other cases it will be the battery terminal on the right hand side of the engine bay. i.e .the black plastic box with the "+" on it. More importantly, you have to make sure that there is no continuity between these (different coloured) wires. Do this with the battery cutoff in off and the alternator plug disconnected.

Can you use the diagram to check the wiring of the ignition lock? The symbology is not always clear to beginners, but the pivoted "leg" attached to the red wire represents the commutator. Depending on how much you turn the key in the lock, the leg can sweep across all the other contacts at the same time (shorting them together, putting battery power on the other contacts). Perhaps the commutator has been damaged and there is always a short between the red and blue wires.

Perhaps Tom has some simpler suggestions.

 

Can you figure out which plug on the column is for the headlight/wiper-washer switches. It has 20 pins. If you disconnect that and the lights stop misbehaving, it might be a sign that the light harness is damaged in the column and not further downstream.

Here's the lighting diagram for the 5.2 USA car. I assume you are in Norfolk, Virginia, and not Norfolk, England. I used to live in the latter.

F355 5.2 USA Lighting Wiring Diagram

I'm not sure where plug 41066 is. The blue/yellow ("LG") wire on pin 7 of that plug controls the headlight pod up/down motion. It sounds like it is getting an intermittent short to power. I guess you could pull relay "D" in the forward luggage compartment and check for spurious voltages on the relay coil (with the ignition harness plugged in). The coil is on relay socket contacts 85 & 86. Normally, one pin should have a solid earth, the other shouldn't have anything until you turn on the lights (ignition on, of course).

Interesting. Did you disarm the immobiliser prior to this?

Somewhere on the forum are photos of a damaged 348 ignition switch. Quite messy... and, I recall, expensive. I can't remember if a cheap Fiat substitute was found.

By the way, I'm having problems understanding the sequence of events. Why did you change the alternator and did the crazy light behaviour begin directly after the alternator change? Did you mention this in a different message thread (sometimes I lose track of who did what). Was there any other maintenance work done recently?

 

Here's the message thread on the damaged 348 ignition switch:

https://www.ferrarichat.com/forum/posts/146235069/

Of course, if you fitted the Fiat ignition switch, you would end up with different keys for the ignition and the doors.

 

Ah... Here's the Euro lighting diagram (sorry, no UK version, but it's probably closer than the US one)

Fig8_Lighting_Diagram_5.2

The colours don't always come out properly in prints, but there is a colour code chart on all my diagrams.