LEDs only work when vehicle is running

Just replaced my cab lights with led units. They work fine if it the vehicle is running. If not, nothing. Any ideas?

 

Welcome to TW…..did they work normal before the LED’s

 

They worked fine before. Whether or not she was running. I'm just confused because the led units need less whats. I belive it possibly is confusing the system, but..?..

 

Gonna have to check and see what you have…do you have power or ground when the truck is off?

 

It's the dome light timer system. LED's dont work with it. If you put in the regular bulb back in the dome light, then the map lights will work when the dome light is on. I couldn't find an LED that worked with that system and just gave up.

 

Thanks. Just seems odd. They all work fine in auxiliary and when she's running. I replaced all the cabin lighting on my 35 sailboat. All work perfectly.

 

Thinking of installing an auxiliary lithium battery for camping. Curious to see if that has any impact.

 

I replaced dome and map lights with LED, and they work exactly the same as before, just brighter. Those lights are now actually useful.

 

If you'd share the ones that worked for you, I'd love to try them. Does your dome light have the timer/dimmer feature?

 

Try turning them around. Some LED's are picky.

 

Got mine from this TW vendor, as he knows what to supply for all applications:

https://www.tacomaworld.com/threads/jumpers-leds.176932/

The dome light goes on and stays on when you hit the unlock button on the key fob, then open and shut the door, then dims and goes off. It also goes off as soon as you start the vehicle, if you do that prior to the timer running out.

When you get out of the vehicle and shut the door, it stays on for a bit, then times out, but goes out right away if you hit the lock button on the fob.

All the timer/dimmer functions are the same as when the lights had oem halogen bulbs.

 

It has to do with the body ECU not providing power unless it senses connectivity to ground and the difference in the resistance between LEDs and incandescent bulbs. There's some bulb that have the correct resistance and will work, else you can solder some resisters in parallel to get things to work. See this thread or an even older one for more info