Help, using the dome light power as a control signal to a relay.

[Monty]

I did this on an 05 Tacoma. I feel your pain. I was annoyed by the relay chatter myself.

I just fixed it last night. I got rid of the relay all together because the dome light is constant hot, and it grounds out to turn on. I believe it is written in the computer to slowly change the resistance as the dome fades on/off.

I run power from a separate fuse block. The ground goes to the on-off-on switch. One side taps into the dome ground at the ecu, the other to constant ground.

Now the rock lights come on when I unlock the door as does the dome light and any time the door is open. Flip the switch to turn them on whenever I want. Works great!

Hope this helps in some way.

 

[DaveInDenver]

I just fixed it last night. I got rid of the relay all together because the dome light is constant hot, and it grounds out to turn on.

So you are running the rock lights directly from the dome light feed? If you take the fading side of the dome, you will probably burn out the transistor (this is the variable 'resistance' part) that controls the dome eventually.

 

[DakarTJ]

I did this on an 05 Tacoma. I feel your pain. I was annoyed by the relay chatter myself.

I just fixed it last night. I got rid of the relay all together because the dome light is constant hot, and it grounds out to turn on. I believe it is written in the computer to slowly change the resistance as the dome fades on/off.

I run power from a separate fuse block. The ground goes to the on-off-on switch. One side taps into the dome ground at the ecu, the other to constant ground.

Now the rock lights come on when I unlock the door as does the dome light and any time the door is open. Flip the switch to turn them on whenever I want. Works great!

Hope this helps in some way.

Thanks for you help. Would you mine drawing a circuit for me?

 

[Monty]

Thanks for you help. Would you mine drawing a circuit for me?

I will give it a try, I'm not really computer savvy...

So you are running the rock lights directly from the dome light feed? If you take the fading side of the dome, you will probably burn out the transistor (this is the variable 'resistance' part) that controls the dome eventually.

The rock lights are on there own circuit. I am just using the dome ground when I want to use the rock lights as courtesy lights.

On my truck the dome has a constant 12v running to it, grounding it turns it on.

 

[Monty]

Hope this helps...

 

[MoGas]

Hey, great to see you over here. I did a "Sedona Fest" gig with you a couple years ago. Lots of rain the days prior made it a bit more interesting.

Anyhow, I really like that idea about the lights coming on when you open the doors, but sorry I'm no help in this thread.

Dave

 

[JamesDowning]

Adding a small capacitor parallel to the switch-side of your relay may help... it would act as a low-pass filter. In this case, your ~0.5 Hz fade signal would be the 'high speed' signal that you wish to filter out. I believe that would call for a larger capacitor, but I don't remember all of the equations from dynamic circuits class... However, if I am recalling correctly... it should reduce some of the relay chatter. Of course, it may end up making it worse... I'm having trouble deciding.

Your other options would be a finding a relay with a lower trigger voltage that still operates at 12V... or... a solid state relay may also rid you of some of the chatter.

Just throwing out some ideas.