Buy some resistors. You can just attach them to the wires with some cable clips (not sure if that’s what it’s called, but you don’t need to cut the wires).

Found a link: mxuteuk 4pcs Led Resistor Car Load Resistors 50W 8ohm for Fix LED Bulb Fast Hyper Flash LED Turn Signal Lights, Fix Error Flash Controller, with 8pcs Quick wire Clip 50W-8RJ-4 https://www.amazon.com/dp/B0838XHWR5/ref=cm_sw_r_cp_api_glt_fabc_G560MGACHHFGRF3R4HVT?_encoding=UTF8&psc=1