My front direction indicator bulb is not working good, this bulb has three terminals, according to user guide, it's 21W. can i use the following LED bulb for replacement? this one is 2.3W only. thanks.

YITAMOTOR BA15D LED Bulb

 

Why? just put regular bulbs back in. You might end up with the Turn signal flashing too fast (because less current is used) and /or bulb out indicator (usually not with the turn signals or front parking lights)

If there are three terminals (two on the bottom and the ground on the side) most commonly that's an 1157 (if the side line up pins are staggered) and there is a 5 watt filament in the bulb also - usually for the parking or side light.

Edit: 2004 s80 - you will definitely get a too fast turn signal flash. And with some of those it's the actual socket (not the bulb) that causes the bulbs to malfunction. (you put a new bulb in and it's not fixed until you replace the socket also) A three terminal grey socket is a 9178546, if it's a black socket and there's only two wires - it's a 9178545