After a long search for answers I still cant fix my reversing light problem so thought I'd try one last go here before giving up. I'll explain what gone on so far.
So ive never had working reversing lights since I bought the car (156 2.4jtdm SW). The bulbs work and connecting power directly to the units makes them work. If I then go to the gearbox and put a tester across the two poles on the sender switch ( just under the battery tray) I get continuity when I select reverse ( telling me the sender works). So I took out the interior and physically traced the wires from the rear lights back as far as I could until they reach a three pole plug situated just at the base of the gear stick on the side wall of the center tunnel in the passenger foot well. That plug isnt connected to anything and there is no other plug anywhere nearby to plug back in. The three poles consist of one live and two i'm assuming neutrals. If I connect one of the neutrals to the live then my reversing lights come on.
As a temporary fix I am using a rocker switch connected to these two wires to manually switch on my lights whenever I reverse. This has obvious draw backs so I ran two more wires from the sender switch on the gear box all the way up to the plug and connected them together. Now this didnt work. My assumption would be that the sender switch would do exactly the same job as the rocker switch and complete the circuit, switching on the lights. It doesnt and so then causes my confusion.
Is there any auto electric experts out there that might know the answer to why this fix doesnt work? In my experience and basic electrical knowledge then I just cant see why it should. The rocker switch works, the sender switch seems to be working, so why doesnt the sender do the same job as the rocker?
Any thoughts or advice would be great. If I fix this then with any luck that s my car sorted until the next issue shows its ugly face.