So I'm noticing that people are randomly installing relays with their HID setups because either the manufacturer recommended it for whatever reason or included one with their product. I personally am a minimalist and the less electrical mess to diagnose when something goes wrong the better.

According to the AWG (American Wire Gauge) chart, our wiring is good to 14 Amps for both the low and high beam wiring, so GM in their wisdom decided to be conservative and include a 10 Amp fuse for the wiring.

So let's break it down by reasons I've seen on this thread why you need an HID...

The factory wiring can't handle the load from the HIDs
Some people think that for whatever reason as soon as you overload factory wiring it'll start your car on fire, it won't if you left the 10 Amp fuse they installed when they built you car. I really doubt an electrical engineer from GM would put the wrong sized fuse in your car. So let's assume the wiring is capable of safely carrying 10 amps of current.

If you don't blow fuses when you turn on your HID ballasts (when they draw the most current), then your wiring can handle the loads.

A relay can help with flickering
A relay is just a electromagnetic switch, it does nothing for flickering. Flickering is caused by a bunch of things including bad grounds but it's usually because your car can't keep a steady clean power supply and these ballasts are pretty picky about that. What you should be installing instead of bulky relay wiring is a diode and a capacitor to soften the power for your bitchy ballast. Interceptors gauges seem to have this problem too.

The HID company told me to
It's general advice for every application, some wiring may not be able to handle it. Also some cars have headlights that turn off when the signal light on that side is on for visibility (Chrysler does this), so you'd need a relay with a signal from both low beam wires to keep the HID lights on all the time unless you want to risk burning your lights out by being turned on and off a lot but our Cobalts don't have this problem.

That and they're in it to make money, one of those relay harnesses would cost me about $5 to make, and they sell them for $10-$20. I'm sure they make those harnesses in bulk for $2-$3. Big profit margin, I'd sell the **** out of them and tell everyone they'll make your car blow up without them.

But hey, if it you feel better to have excess wiring in your car to diagnose when something does go wrong, be my guest. I can also run my 100W halogen high beams off the stock wiring and I still haven't blown the factory fuse in the three years I've had them.

Any other myths we should disspell? There's a lot of them on this forum for just about everything and they drive me nuts.

 

Pretty legit points. Completely agree. I have ran harness setups in different apps in the past but denlou makes a very valid point

 

"A relay can help with flickering
A relay is just a electromagnetic switch, it does nothing for flickering. Flickering is caused by a bunch of things including bad grounds but it's usually because your car can't keep a steady clean power supply and these ballasts are pretty picky about that."


Don't forget the most common problem, which seems to be the DRL interaction with the headlights because of their operating voltages.