2020 2500HD LT running lights

[Greg Nelson]

My left front upper running light does not work.   Replaced with a new Lasfit led bulb and checked fuses.  Any ideas?

[64BAwagon]

The LED's can be polarity sensitive, try pulling it out and rotating it 180 degrees.  I assume youre talking about the parking lamp/turn signal bulb. If the turn signal works right now and the park lamp doesnt youve got another issue. 

Edited December 26, 2023 by 64BAwagon

[carkhz316]

Do you have halogen lamps or LED lamp assemblies? The stock halogen assemblies require a "CK" type of 7443 bulb, whereas the LED lamp assemblies use just a standard 7443 (really a 7440 since its only the HIGH filament used). But also check polarity as mentioned, as while LED bulbs are typically polarity sensitive, few manufacturers build them in a way to facilitate universal installation.