LED tail light resistors

Ok fellow minitruckers! I've gotta Hardbody and I shaved the whole back end and I've got LED tail lights. My problem is I have the computer module hooked up to it and of course my turnsignals blink fast.The instructions say add a 5watt resistor inline but it didn't fix it. I tried it directly inline and spliced over to the ground like mine were on my s-10. Now the instructions didn't say anything about the ohm load on the resistor but they're 5watt and the ohm is very low. I know they sell resistors at the local parts store but they're more than 5watts and do have a higher ohm load.Again I've done this on my old s-10 and never had any problems. What am I doing wrong?