Thread: Turning signal relay?

Originally Posted by marines542

But to be honest I don't think they'll work....there isn't a constant 12volt source to the turn signals when using them...its an on off power supply

The "flasher" in 2004 and above Grand Prix is indeed in the BCM, and the noise is generated within the instrument cluster.

Each incandescent bulb has 21 watts of resistance. "Flashers" need that resistance to control the speed of the flash, and when the resistance isn't there, the remaining bulbs will "hyperflash." This tells the driver that one of the bulbs is burnt out. It's a design feature of the system.

On older cars with the old 552 flashers, you can get a "LED" version that ignores the missing resistance. With the modern flasher integrated in the BCM and cluster, you're forced to use those ugly resistors others are telling you to use. You'll need one at each LED location.

These things are beefy resistors...as resistors go. If my math is right...and that's no sure thing...21 watts at 12 volts gives about a amp plus draw. Even at 50 watts, those suckers are gonna get hot. They will melt plastic. The standard recommendation is to mount them against metal and away from plastic.

It's amazing how much current a tungsten filament will carry.