What voltage diode for Air Bag Code 27 fix?

[quick_4.6]

I replaced the burnt bulb in the passenger de-activation switch last night and the air bag light stop blinking "27". My question is what voltage diode is needed? I tried a 3v and it burned out after 1-2 seconds. I installed a 12 volt for now. It works but it's a little dim. I tried to read the voltage but my cheap meter is unreliable. It was reading 4 volts.