ok this post is a week old, but I just returned from my vacations. Marty - did you try to use a resistor instead of the relay ? I mean a let's say 470 Ohm to 1k resistor in parallel to the diodes ? Just a suggestion because it is easier to install and much smaller. Elvis That somebody was me. The cruise control systems I tried (Audiovox and Dakota Digital) required a ground to be present through the wire that connects to the brake light switch when the switch was not active. Regular bulbs will present this ground to the wire through the filament of the bulb. LEDs have such a high impedance that there is virtually no ground present on the wire anymore. Adding an LED 3rd light to a system with conventional bulbs still in the brakelight sockets will work fine, since the regular bulbs are conducting to ground. The solution for changing the regular brake light bulbs to LEDS is to install a relay in the brake light wire which will toggle between a known ground reference when off and the +12v of the brakelight circuit when the pedel is pressed. I am in the process of documenting how I did this and will post the scheme soon. Marty Galbreath #3765 To address comments privately to the moderating team, please address: moderators@xxxxxxxxxxx For more info on the list, tech articles, cars for sale see www.dmcnews.com To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews Yahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/dmcnews/ <*> To unsubscribe from this group, send an email to: dmcnews-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/