Hope this is in the correct forum. I have been doing LSX conversions in old trucks for several years now, but just came up against something new. I put a DBW LQ4 in a 1966 Chevy C10 with LED brake/tail lights. They are the ones that have the circuit board built into them and not just a replacement led bulb that I can throw a load resistor in the ground. I of course had to upgrade to the led flashers to get them to blink, but my TAC module is not sensing a load through the lights ground to the brake switch and allowing the cruise to activate. I know there has to be an easy solution to this? My first thought is a resistor in this wire from the brake switch to the TAC, but I believe the PCM will throw a code for to low or high of voltage through this feed. I need someone to help me think this through, Thanks guys!

 

You should be able to add a load resistor just as you would with any other LED light. It makes no difference whether it's a plug in bulb or a complete LED circuit in the lamp - the LEDs are not drawing enough current. Adding a load resistor just brings the load back up to what a standard incandescent bulb would draw.

BTW, load resistors aren't normally installed in the lamp ground circuit. Usually, a load resistor is installed in parallel to the lamp (i.e. from the lamp's power to ground - usually the lamp's ground wire but any ground will do). Installing a load resistor in the ground circuit would be in series and would have to be a smaller resistance than the 6-ohm 50W resistors commonly used... 1.5 ohm would be about right.