Hyper Flashing - Stymied

The hazard may not use the double flash rate safety circuitry in the turn relay, hence the normal speed.

Which earths did you find? There are different ones for each bulb (almost). On my Euro-based 5.2 car, there is one above the right hand radiator (outboard) mounting bolt for the rear right hand lights. A faulty earth here, though, may cause the other tail lights to flash slightly. It would be best to remove the earthing bolt and clean the mating surfaces, rather than just doing a straight resistance check. Resistance can vary with vibration, temperature, etc. Good luck finding that bolt... You will probably need to find the left hand side earthing bolt first, then figure out where it is on the right hand side.

I wasn't sure which earths in the front luggage compartment applied to the turn lamps, so I cleaned all the ones I could find.
The earthing for the (single) side repeater lamps on my Euro car is somewhere inside the cabin (I wasn't able to find it when I had a double flash problem). Did you check your side repeater lamps and holders?

I don't think the double flash safety circuit looks at the resistance of the steering column switch, just at the bulb circuitry. If the column switches are faulty, they would probably just make the turn signals work intermittently or not at all.

Good luck!
Cheers
Ian.

P.S. Your profile doesn't say where you're based. You have a US car or Euro car?

 

P.S. Did you make sure you had the right wattage/voltage lamps (as per your handbook?)

 

Yes (but have lost access to the 355 schematics so can't suggest how to make a test connection that would simulate a properly closed RH turn signal switch).

 

If you remove the relay from the holder and put the red lead of a multimeter into the relay holder socket which corresponds to the white wire, and the other multimeter lead to a known good earth (metal of steering column?), then turn on the ignition and activate the right turn switch, you should see a constant 12 volts DC from the battery. On my car's relay holder, the white wire goes to the socket marked "3". Be careful, one relay holder socket is always live (direct from the battery) so don't randomly stick your multimeter (set to resistance) into relay holder sockets.

It gets complicated if you want to simulate a right turn with the relay in-situ (you would need to access the plugs in the steering column or short out sockets at the back of the relay holder.

I still don't see how the switch would cause this effect though. Why should it?

 

IME, an unwanted high resistance in that turn signal switch connection (that isn't infinite ohms) causes rapid signal flashing (not an explanation, just an observation).

 

I know said it before and I know you say you have checked everything. But, my '96 355 Spider did exactly the same thing as you describe. EXACTLY! Like the man says, unwanted high resistance somewhere in the circuit is almost always the cause. I cleaned my tail light bulb contacts themselves as well as the bulb socket contacts and my turn signal returned to normal and has stayed that way. If you are absolutely positive you've done it, then forget it. If not, then check it again and be double sure the bulb and socket contacts are perfectly clean. If these are perfect, look elsewhere in the circuit for unwanted high resistance and clean everything one by one. My guess is you'll find it.

 

Interesting, thanks.

When you think of a relay, you assume the control circuit is independent of the output circuit (especially with an integrated circuit wired in, like the F355 relay)

 

If you do decide to shotgun the system (replace parts ad-hoc) until you find a fix, it can get expensive. I replaced side repeater lamps, a section of harness going to one of the front turn lights, a diode and LED in the hazard switch and a turn relay. The relay was new and identical to the original, but it caused BOTH left and right indicators to hyperflash (faulty relay ex-factory?). Thankfully I received a refund on the relay.

Unfortunately, it's difficult to isolate the various legs of the system to do resistance checks. You have to disconnect plugs on front, rear and side lamps, but also on the hazard switch and instrument panel.

The following diagram may help with diagnosis. The original diagram was based on a 1994 Euro (non-F1 car), but modified to show information which reflects later model cars. Unfortunately, I don't know what is involved with Scud Ing modification.

http://www.iinet.net.au/[email protected]/FerrariF355Spider/FerrariF3551994LightingDiagram.gif

On my 5.2 Euro car, the 7 pin relay fits into a 9 socket holder which has numbering (on the plastic) to identify the sockets. If your socket numbers correspond to the same wire colours at the back of the holder, then this diagram might prove handy for you or an automotive electrician.

Cheers
Ian.

 

Sorry, I removed my link to the wiring schematic. FerrariChat have removed the manuals/wiring diagrams from their site due to copyright problems. I wasn't sure if my new, improved diagrams also infringed on these copyrights (????)