The previous owner had them in my truck when I bought it and I replaced them. The cheap bulbs you get from the parts store are just that, cheap. They don't have any diodes on the sides so the light patten is narrow and you don't get much light in the housing. There are some online vendors with better products that would likely work better. And yes you will need a resistor to have your flash pattern right.
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My Truck: '03 F250 CC SWB Lariat, 7.3, auto, aFe 4" straight piped, DIY Tymar intake, GTP38R on a blank pedestal, TS 6-position with canned tunes, AIH delete, boost fooler, CCV mod, Iron Cross wheel-to-wheel HD Steps
Farm Truck: '93 Ram D350 Club Cab, Cummins, G360, pump tweaks, 366 spring, DennyT Stage II pin, BHAF, Diamond Eye 4", SDX 5x.012s