Headlights Stopped Working

I have been putting this day off for 10 years but now am forced to confront. When I purchased my car I knew the car had been rewired at some point in its life. The headlights have stopped working so I need to trace the problem. I can hear the relay clicking but no lights. After removing the dasboard it appears that the existing wiring was modified to accommodate the insertion of numerous relays. Starting off I had a number of questions:

1. Is there a wiring diagram for the S2 Vixen? Lacking that do the wire colors match the standard British car colors?
2. Being a novice to electrical issues any idea why so many relays? I can only think of the normal ones; horn, headlights.
3. As a side bar, does anyone have a photo of their dash inards? I was curious how the steering column is supported. On my car it is supported by a bracket on the rear of the dash and attached by a radiator clamp.

Thanks,

Gary

Ok have resolved most of the problems and am down to the final one. My tach has been flaky since I bought the car. I am replacing it with another electronic tach from a Spitfire 1500.

My question relates to the wiring on the existing tach. Any idea of the purpose for the wire loop on the back of the tach? On the 1500 there are two leads, one for (plus ground)power and the other to receive the signal from the coil to register the firing of the cylinder and the thus convert to an rpm value. (Do I have that correct?) On the existing tach there is only one wiring connection (plus ground)which looks like for the power. Does the loop on the back of the existing tach produce some sort of inductive pulse which the tach reads and converts into an rpm?

Thanks,

Gary

Gary- Is this the TVR?
Is it a 4 cyl?