right guys im wiring in my boost gauge to my light switch.

theres 2 possibles for neg. black and red or black n white??

which one is it please?

Do you have access to a test meter or similar. You can make a suitable tester with a couple of bits of wire and a lamp.

Do you mean which wire on the car is negative? cos if you do then i believe brown would probably be an earth on a skoda but if your unsure then earth it direct to the body of the car behind the dash

it says wire it to -ve

i presumed it would be just black

-ve on all European cars (often excepting French!) and certainly Skoda is brown. Certainly NEVER black, or multi-coloured.

Black and red and black and white are likley to be the two separate side light circuits, live (i.e. +ve) one each for right and left.

My advice go get a manaul (such as Haynes) and a test meter/12v test screwdriver.

PS there are not ususally any earth (i.e -ve) wires going into any switches unless they are lit (in which case the bulb will need an earth contact) as the switch only switches the item on/off. The earth contact is therefore at the item being switched. So a light switch will have only live wiring, main in then different live connections out depending on which selection had been made by the switch. The light then gets a live input and has an earth contact direct to it so it can work. If the switch (like the Octy light swicth) has a lit area so you can see the symbols int he dark, there is usually a tiny bulb, which will need an earth contact, however this will eb a very thin cable and probably not suitbale for nay other purpose than the min-wattage bulb it connects.

The whole bodyshell is -ve (directly connected to the battery -ve terminal) so the earth contacts run to a bodyshell contact. As the dash is all plastic there will be a multitide of brown cables running to earth, so that any lighting, or electrical instruments/radios etc, can work. There is almost certainly a main earth point too, on to the bodyshell, make sure you choose a think enough cable to join to, or run a separate one to a bodyshell contact.

to when i click it to sides and ive earthed the other black as i found a guide

easiest is to identify the fuse supply for the parking lights - tap into the fuse itself by twisting some wire about one of the terminals and stuff the fuse back in(yes I know it's a little rough - but it works).

You can take the negative off any convenient bolt/screw in the body.

IF it's a mechanical gauge with a lightbulb, not an LED, and is insulated from the body in a plastic pod, it doesn't really matter about polarity..

You can make up a tester from a piece of wire and any spare 12V bulb. One end to the body and the other to identify/confirm the fuse. Park lights switched on= tester bulb lights up...

HTH

Bas

anyone know where ya can get new t pieces from?