Neutral gear safety switch

[David C]

My memory is letting me down. As Dodd says the reverse switch is on the shift lever and the neutral inhibit on the gearbox. A bit of research suggests that the culprit in your case is the lever inside the gearbox that operates the switch. This is known as a Rooster Tail due to its shape.
Be aware that there are at least three different types of switch and Rooster Tail. Pre about 1970 - per the 410 - the switch had a single contact and only inhibited the start. After this the switch had 3 wires and dual function to include reversing lights.
It seems it is possible to change the rooster tail with the transmission in the car but I can't immediately tell whether the valve body has to be removed.
You may want to consider a couple of upgrades while you are about it. The simplest is to swap out the pressure regulator valve for Sonnax 22771A-02K and the manual valve for Sonnax 22771-09. This allows the transmission to fill in Park and saves the "clunk" when engaging drive.
The other upgrade is to replace the valve body with a slightly newer unit to allow part throttle kickdown.

[Sam410]

I had the opposite problem on my 410 - it would not start at all on a trip to France. I managed to work out that it was the inhibitor switch that had failed so using some stout logs found at our gîte as axle stands, I bypassed it so that it would start in any gear. I was very careful to double check it was not in gear when starting for the rest of the trip.

[Roger Morrall]

Originally Posted by Sam410

…… so using some stout logs found at our gîte as axle stands, I bypassed it so that it would start in any gear. ………

Sam - that all sounds an immense amount of hard work when all you needed to do was to open the bonnet to connect an earth to the solenoid as per my previous post. But you did do much better than me at not starting the engine whilst in gear!

[Sam410]

I don't remember the precise details now, but whatever it was I did it was easier to reach from underneath the car!

On another French trip the ignition switch packed up and after phoning SLJ for instructions I spent a thousand miles having to hotwire the car at every start. It has just been rewired with a new loom so I hope these travails are behind me now... (Touches wood!)