How exactly does an heavier duty harness work?

[IsLNdbOi]

Ok, I was about to shell out some money on these harnesses:

http://store.racinglab.com/kyoplheduwih4.html


Question though. How exactly do heavy duty harnesses work? These things look like a small extension cable or something. If they're supposed to prevent too much voltage from frying your stock harness, but that voltage still has to go through your stock harness to go through the heavy duty harness (attached to the end of your stock harness) how is that helping? Or are these meant to completely replace the stock harnesses?

[paultyler_82]

Ok, I was about to shell out some money on these harnesses:

http://store.racinglab.com/kyoplheduwih4.html


Question though. How exactly do heavy duty harnesses work? These things look like a small extension cable or something. If they're supposed to prevent too much voltage from frying your stock harness, but that voltage still has to go through your stock harness to go through the heavy duty harness (attached to the end of your stock harness) how is that helping? Or are these meant to completely replace the stock harnesses?

Thats because those KYO's are junk... a real harness should plug into your exsisting plugs, but should only use their signal to switch a relay on the harness... the new wires that actually power your headlights are much higher guage than the OE units, and have a direct to battery connection. Heavy duty harnesses are not compatible with DRLs, however.

[IsLNdbOi]

Where can I get some heavy duty harnesses that have direct power connection to the battery?

[paultyler_82]

Well, it depends on whether or not the Yaris has a switched ground system, if not, rallylights.com stocks em, if it does.... I dunno who makes a harness for a switched ground system.

[IsLNdbOi]

What's a switched grounding system? This is the first time I've heard about this regarding harnesses.

[paultyler_82]

Basically, there's two ways to work a headlight, switched positive, in which the switch exsists between the positive side of the power and the headlight. In a switched ground system, the switch lies between the negative side and the bulb... I'm not sure why it makes a difference, but apparently it does.