Which bulb?
 

Just a quick question, mainly for those of you with cab marker lights. Has anyone ever used the 194na (yellow bulb) in your cab marker or side marker lights? I have several bulbs out and was wondering if it would make a difference, instead of the clear bulbs. I am gradually swapping them all out to led, just haven't gotten them all yet. Thanks.

They'll work, may be a bit dimmer, but more orange. White led's will make them more yellow, its recommended that you color match the led's to the lens by most companies, to prevent color wash out.

I wouldn't use the yellow or amber bulbs behind a red lens but the front amber markers or the cab lights should be no problem.