7th Cavalry

Ok,so about a year ago I installed lights under the dash so that when the door was open/dome light on, it would illuminate the foot wells. I used 1157 bulbs and sockets, wired in series. Starting with the BG wire (right side of dome light), and grounded on the floor board. Worked wonderfully. A couple days ago I got led bulbs, dome light works, but big surprise floor lights do not. Would like suggestion on proper wirering to make this work. I have led load resistors, but not sure if they're needed, or where they should b wired in @. Thanks in advance

Joe428

Two theories are coming to mind right now.

First, did you wire the foot well lights so the current has to flow through the dome light? LEDs are not a physical electical connection like a filament is.

Second, are you sure the polarity is correct on the foot well lights? LEDs have to be wired in the correct polarity where a filament does not.

You should only need resistors if your LED set is below 12v. For example, if you wire four 3v LEDs in parallel you have one 12v LED. If you have less in parallel a resistor may be needed. The voltage should be listed on the LED or the spec sheet.

7th Cavalry

Thank you sir, for the info. I didn't know that led were not a "physical" type of path. Or about the voltage #, or calculations for said #. I did know about correct polarity. Question, which dome light wire should I tap to get my pos.? I'd like them to work when doors open, and when dome is switched on. Still wanna keep my ground on the firewall. Thanks again

Joe428

For clarification, LEDs do pass current but not in the sense that a filament will. Wiring them as a pass through can lead to poor performance. LEDs have and anode (+, longer tail) and cathode (-, shorter tail). You should be able to use your normal dome positive. This website has info on the topic
Quickar Electronics HOW TO HOOK UP LEDS - choosing the correct wiring scheme, the proper current limiting resistors and verifying performance