Need help with relay logic for underbody lighting

I do not think that there is one that will drive the relay circuit.

 

I do have the signal mirror covers.This lines are very low current lines to power an LED array.
The relay circuit you want to implement more likely will overcurrent such lines and probably ruin one of the body ECU.

 

In your other post, you said your under body lighting will pull 18 amps. Why are you using a relay rated for 10 amps?

 

Yes, the OP's proposed relay has a coil that is spec'd to draw 3A at the coil? That is crazy high current draw.

Compare to this run of the mill automotive relay that draws current in the mA (milliamp) range, that could be used with the dome light wire as the signal wire to switch power to the under body lighting from the fuse box.

http://pages.ebay.com/link/?nav=item.view&id=291469674220&alt=web

 

Ha, good question. I don't know where that 3A came from.

Thirty something milli amps should be fine.

The dome illumination wire should be fine.

 

The problem U are facing is the reason of "WHY" I didn't recommend your suggested tying point.

 

I would recommend getting the signal mirrors with puddle lights, which illuminate along with the dome light.

 

Were those a Toyota option? And if so, do they just on/off illuminate, or do they fade in/out along with the dome light?

If they just on/off, then you know it's possible, and you could skip buying the mirrors (unless you want the mirrors) and just glance in the wiring diagram manual to see how they're designed to tie in, and that would be great giant hint you could follow to tie in the underbody lighting.

If they fade with the dome light, then it's not quite so simple, but you've got a couple options: use a Schmitt trigger to watch the dome voltage and power your relay when it crosses a threshold and stop when it crosses back (a Schmitt trigger has two slightly different thresholds, one for each crossing direction, exactly so it doesn't do what your relay was doing and buzz on and off when the signal is near the crossing). Or, it might look extra cool to build a voltage follower and really have your underbody LEDs fade on and off like the dome light.

That would be a lot like my own first car project out of college, when I bought a Mazda 323 and it really bugged me that in the factory radio (!) the illumination didn't dim with the rest of the dash, even though the radio did have a separate terminal for illumination power. I didn't want to risk just adding it to the load on the dash dimmer, so I made a follower using an LM358 opamp and LM317 regulator, worked great. These days it's probably as easy to get a variable switching regulator as it was then to get the 317.

I get the sense that this project you've given yourself will require you to go a bit deeper in electronics than you have before ... maybe that makes you afraid of TMI but it sounds pretty cool to me. My favorite way of learning new stuff always has been to give myself a project I can't do without learning it.

Anyway, if you're game to do it, you are still likely to find the wiring diagram to be an important reference for you. The questions you are running into are exactly the sorts of questions it answers. You may very well find a generous PriusChatter to solve them all for you, depending on who is between projects and has the time to do it (that isn't me at the moment, unfortunately), but if you don't find someone to step up, at least you know where all the information you need is, and the forum is still here when you have specific questions about it or you get stuck; a lot of people who might not have time to work the whole thing out for you probably still have time for pointers when needed.

-Chap

 

Someone can correct me if I'm wrong, but I believe the puddle lights fade on and off along with the dome lighting.

 

I do not have them connected in that way; my white puddle lights go on solid as I approach the vehicle and touch the door handle; but this are only a few LEDs load.

 

Then, perhaps you can help the OP out by telling him what wire you use for power to your puddle lights? The OP will use a relay to switch power to the load, so only a light current will be needed to switch the relay via the coil. Main power will come from the engine fuse box.

 

David,

What trim level Prii do u have?

If u have the footwell lights, maybe u can u this to serve both ur needs. They turn on when u unlock (can't remember about approach) & they stay on with the headlights

VS980 4G ?