Dome light

Hi Guys, it seems I got the mysterious dome light wont turn on when doors are open, checked dome switch, door switch, fuses everything is ok, any ideas how to solve this thing?

 

Bulb?

 

I wish it was the bulb... but its not, it works in on position, its not door button; I have the beep when the key is in ignition and door open, its not the dome switch; I tested it.

 

You should test with a multimeter if the dome is getting power when the door is open.

 

Zero volts to the dome on open doors.

 

Strange, I guess just trace the wires and make sure something isn't unplugged or got yanked out of it's connecter

 

I tried to, but I have to take off the headliner , there are some wires passing on the floor , but they are like 20 wires, very hard to trace. Ive been looking in the forums, some members had the same issue, but nobody posted the solution. Im wondering if the body ecu might be defective, or a relay responsible for this function.... but got no clue yet.
Thank u for helping

 

No problem, and the wires for it go down the a pillar on the driver's side so you can start there so you don't have to remove the headliner

 

Yup, so far thats my only option to go.

 

hopefully this helps a bit.

 

What year?

 

2003 xcab v6 trd a/t

 

Fine, the above wiring diagram will be good. The earlier years do not use a "body ECU".

 

I would be VERY suspect of the stupid dome switch design. Mine doesn’t like to work when I’m the “on” position. That little ball bearing isn’t the best for making ground connection...

Also I believe our dome lights are ground switched, not got switched i.e. always should have power, and only gets ground when doors are open. It may be a burnt fuse for hot supply?

Also check the map lights as my dome/maps were acting really funky when converting to LEDs. They are tied together somehow and needed to see resistance for the on with door open to function correctly.

Good luck

 

Checked that, didnt like the design too, so I shorted it with a piece of wire... no voltage to the door postion, voltage to on position is always there.
Map lights work normally
Thx

 

Update!
Traced the wires today, it seems the body ecu is defective, my plan is to remove it this weekend and attempt to fix it. Any thoughts on this?

Thx

 

Were you or are you using LED bulbs? There's a 3watt resistor in the body ECU/integration relay that was burnt in mine. You can get the circuit board out of the fuse box fairly easy.
You just have to unbolt the fuse box and turn a little to allow you to remove cover. It snaps on. I don't remember resistor size.

The light should always have power unless they were left on to long. example forgot to turn them off over night. The body ecu controls the ground to turn it on and off.

 

Im using the standard bulbs, but anyway thanks for the advise, Im gonna try to remove the junction box/ fuse box/ body ecu, and try to check the board elements. I hope it will be easy to diagnose and fix.

 

I ended up converting my dome to the old style. I wanted to run LED's and resistors just made them dimmer and kept messing up my body ecu.

 

My 04 does the exact same thing, always has. Light works in 'on' position but never when doors are open. I eventually just gave up, but if you figure it out I'd be curious to know the solution.