Hi Guys
I need advice. I am busy putting relays on the sealed beams and then later gonna put in semi sealed with higher wattage output bulbs.
My problem is the following:
I saw that the indicator lights on the side panels are attached to the lights earth on both sides. I disconnected them and earthed the one below at the battery tray and the other side (passenger side) I earthed it behind the horn which is bolted and earthed next to the radiator. I want to earth the lights the same locations. I saw that the thick negative wire goes from battery to the engine and then there is a thinner one going from the engine where the thick one is bolted to, to the battery tray below. Am I save to presume that my setup will work because the whole car body is a negative. The relays also needs to be earthed. The relays I am installing next to the light that is in front of the battery tray.I am going to earth them also to the battery tray below where that thin wire is connected.

I might be going fuel injection with management later and just want to make the setup so that it will not have a problem with the electronics of the future management.

yes your hole body is earthed as long as it metal and clean u will get a good earth

The way I prefer to setup headlight relays goes like this...

I make a separate harness for the headlights and pick the control signals for the relays off one of the old headlight sockets. Makes it easy to move the harness to a different car later.

Pick the power to the relays off the output post of the alternator. From the relays the wires go to the headlights. The negative wire from each headlight returns to the alternator, using one of the case bolts as a terminal. Trigger the relays from one of the existing headlight sockets.

This makes for a compact clean install that provides maximum voltage to the headlights and does not rely on the body shell for the negative current return.

I go overkill and run #12 wire for all the main headlight wiring and use #16 wire for the relay triggering. All 3 cars, the 2 1200's and my daily driver Subaru are wired this way.

1200GXman, would also probably think about putting in a thicker earth to the body than what the stock one is, from memory its not really a huge wire to be supporting all the earth current going through the body, usually you have 2 battery cable sized wires comping from the negative on the battery, one to go to the engine and one to go to the body

Thanks for the replies. They were unfortunately a little late as I connected all the wires over the weekend.Haven't switched on yet. Gonna do it this week somewhere. Need to tidy up a bit.

I earthed the relays and the light in front of the battery below at the metal plate that supports the battery tray.The other side I earthed to the bolt that bolts the horn to the radiator support panel next to the radiator.I noticed that the horn is also earthing this way. I think it will work although I am going to replace that earth wire that PIGDOG was talking about with a thicker one just to be safe.