F355 left hand turn signals flashing fast -&- exhaust valve stays open

Hi guys

Hope someone here can help with a strange electrical issue I have on my 2.7 F355GTS.

I may have two separate issues - or - one combined problem with two symptoms, not sure but these are the individual problems:
1. The left hand side turn signals flash really fast as if a bulb has blown, but it hasn't unfortunately, the very odd thing is that the front turn signal actually flashes through the parking light bulb instead and not the turn signal bulb. This makes us think there is an earthing issue.
2. The butterfly valve on the exhaust is always open. It is normally closed at low RPM and opens about 3.5 - 4k RPM. It is designed to fail closed if there is a problem, so it is either mechanically seized open or electronically held open. The lever and diaphragm mechanism appear to be mechanically free as I can open it close it with my finger so I suspect electrical issues here as well, possible same earth issue?!?!

A friend who also owns a 355 worked with me yesterday to see what we could find. We did not find the problem, but we did rule out what was not faulty which is something. Hopefully someone here can suggest something else to check as we are out of ideas.

We decided to tackle the turn signal issue first. The first thing was to swap the suspect bulb assembly on the front turn signals over with the good working ones from the right hand side - no change. We did the same with the back turn signals, again no change.
We measured the resistance of all the wires on the faulty side against the good side, with bulbs both in and out, and everything was identical. No short or open circuits.

Next check was the flasher relay, I swapped mine with the one from my friends car and it worked fine in his and I still had the fault so that ruled that out.

The odd thing was that if I took the turn signal bulb assembly from the good side on the front and swapped that with the parking light bulb assembly then both the bulbs are matched in resistance and both flash when the indicator is on. Weird... This does prove that the wiring is ok and current is getting to all the bulbs.

If I put the hazard lights on then the speed of the turn signals returns to normal again (higher load?) but it is still the parking light on the left hand side front flashes rather than the indicator.

I also reset the ECU just in case.

Any ideas???

Brian
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It is the standard diaphragm valve, it is not jammed in any way and I can open and close it with my fingers or attach a vacuum pipe to it and create my own vacuum by sucking on the other end of the pipe till it fully opens, when I then blow into the pipe the valve closes fully. Also with the proper pipe reconnected, the moment I start the engine the valve half opens on tick over which it should not do. This is why I think it is electrical and not mechanical.

 

The spring is there and it returns to the closed position as it should when the vacuum is removed. I am confident this is not a mechanical issue.

The turn light issue appeared after I did the ECU reset hoping that would resolve the valve issue. I am not sure if this is a coincedence though.