I made a harness for some fog lights and when i touch it straight to the battery.it sparksis this becuase it needs to go through the relay and fuse to work properly? with no sparks?
You're seeing sparks for one of two reasons: 1) Your fog lites are shorted to ground or the most likely cause, 2) Fog lites are a fairly high-draw item, so a momentary spark when you first touch the battery would be expected. Your assumption about needing a relay is a good idea if your car didn't come with factory fog lites. Using a relay will save you from burning wires that aren't big enough to carry the current, especially the start-up current that fog lites draw. Hope that helps! Mike
the spark is due to the fact that you are creationg the connection without a switchthus you are firing up the lights by direct contact to the battery. This will create a spark every time. you need to run them through a switch to make them operate properly. Basically you are creating a short in the system when touching the wires directly to the battery. Put an inline switch and you will be ok.
Any add-on components need to be fused. Anything that requires amperage needs to go through a relay. Use the headlights or a switch to control the power to the relay. The relay then carries the current from the battery though a fuse to the fog lights. Any other way can lead to big trouble.
