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'15 Ltd, which dome wire is "always hot"

3K views 19 replies 8 participants last post by  YellowFellow 
#1 ·
'15 Ltd, which dome light wire is "always hot"

I could use some help in determining which wire of the three is "always hot" on the connector for the dome light in a '15 Limited. There are three wires, two of them are white with a blue strip and the third is all white, (the all white wire is not in the center of the two white/blue wires). Does anyone know which is always hot? This is for a Homelink mirror that I elected to make the Homelink always hot.

Thank you.
 
#2 ·
A 12V test light or a voltmeter should reveal which one to you.
 
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#3 ·
Tried a voltmeter, but there is no ground near the light. All the metal is painted.
 
#5 ·
Will finish up tomorrow in the daylight. Went to the hardware store tonight and picked up some wire and alligator clips. I'll just make a temp ground wire and run it from the battery. Paint scraping would work, but I'm just not inclined to do that.

Thanks for the suggestions, guys. I was hoping someone would have a wiring schematic of that circuit. I'm so lusting for a Haynes manual for our RAVs.
 
#6 ·
When U install the Homelink where U gonna get D ground? From D battry?
 
#7 ·
Ground is already running to the Gentex mirror for the compass and auto-dimming features. The temporary ground is only for use in identifying which of the three leads into the dome light is always hot.
 
#8 ·
Final wrap-up.

Finally identified which wire is constantly hot, spliced the Gentex Homelink into it, tested, reassembled, and programmed the Homelink. All is well. Verified last night that auto-dimmer and compass work as expected.

The Gentex is model #536. Includes three homelink buttons, auto dimming mirror, and the blue-colored 'invisible window' compass. Would have been a simple 'plug 'n play' if I wanted to leave the Homelink on switched power.

For those who care, as stated in the original post, the dome light connector consists of three wires, a solid white wire and two white wires with a blue stripe. The solid white is not in the center position, but on one of the ends. The white/blue wire on the opposite side is the 'always hot' wire. Again, this is a '15 LTD.

Thanks all for the help. Obtained hardcopy of schematics from the dealership this morning that includes the dome lights and the sunroof controls. They proved to be worthless.

Next up . . . tapping into the switched +12v at the sunroof to power my USB Dashcam so that I can have just a short wire coming from the mirror area instead of having a cord hanging down and plugging into a cigarette lighter socket.
 
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#9 ·
Next up . . . tapping into the switched +12v at the sunroof to power my USB Dashcam so that I can have just a short wire coming from the mirror area instead of having a cord hanging down and plugging into a cigarette lighter socket.
I have a 2016 XLE, but I want to do the same. Ordered my dashcam yesterday (Viofo A119S) and would LOVE to wire up something with the sunroof instead of the long wire. If/when you do it, would you mind posting something to let me know if it might be the same for me? I know our model years are different..

Thanks!!!
 
#10 ·
Absolutely! I changed the order of "stuff". Currently, I need to figure out how to run a hot wire from the trailer light kit through the firewall. I have the wire kit behind all the panels from the back up to the firewall, but am 'stuck' there. Found a YouTube video that shows how to take apart the wipers and cowling underneath to get access to the 'hole' through the firewall in which the main wire harness passes. Just haven't had time to take everything apart to run the battery wire yet. Since I usually take my time, I figure it will take most of a day.


p.s. Mirror works great! Despite the security problem, I love having the Homelink hot all the time. All other functions work as expected, (i.e., dimming mirror and compass).
 
#11 ·
Currently, I need to figure out how to run a hot wire from the trailer light kit through the firewall. I have the wire kit behind all the panels from the back up to the firewall, but am 'stuck' there. Found a YouTube video that shows how to take apart the wipers and cowling underneath to get access to the 'hole' through the firewall in which the main wire harness passes. Just haven't had time to take everything apart to run the battery wire yet. Since I usually take my time, I figure it will take most of a day.
If the video is an install of the factory trailer wiring, I followed it too on the '15 Limited, but instead of tearing the cowl and wiper parts off, I just used a coat hanger wire to push thru the preformed "nipple" from the interior of the vehicle far enough to reach it from the front, attached the hot wire to the coat hanger and pulled it thru the nipple to the front, saved a lot of time. :D
 
#18 ·
Where did you tap into for a "hot with key turned on" wire?
I did not tap into a "hot when ignition on". My Homelink is always 'hot'. Since I usually park in the garage, I'm not too concerned about anyone opening the garage door when it shouldn't.

The eBay vendor sent installation instructions with the mirror. There are two 'wiring kits', one with the mirror always hot, one hot only when ignition on. An extra wire was provided with the always hot kit. I don't know technically why, but the two kits are not interchangeable.

Sorry I couldn't be of more help.
 
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#12 ·
That certainly seems a lot easier. I'm installing the Curt harness, (part number 56166).

Where can I find this 'nipple'? Is it at/near the main wire bundle?

(As a temporary measure, I just ran an extra wire from the battery to the outside rear-view mirror and just closed the door on it. Worked in an emergency, but I wouldn't want to shut the door on the wire too often.)
 
#13 ·
That certainly seems a lot easier. I'm installing the Curt harness, (part number 56166).

Where can I find this 'nipple'? Is it at/near the main wire bundle?
You can see the nipple at about 9:20 in the video, it's almost impossible to see from the front, it too a few tries piercing the membrane to get it thru the nipple, I installed the Curt kit too, just used the factory routing instead of going under the vehicle as the Curt instructions said.

 
#14 ·
Yeah, me too. I didn't like the idea of running the wire under the car. That seems 'dumb' to me. Took longer to take all the panels off, but it sure is a lot cleaner.

With your Curt . . . do you leave the four-pin plug in the spare tire well as they suggest . . . or did you run it out the back through one of those rubber grommets and attach it near your hitch? There is a grommet down low on the left side of the vehicle. I was thinking of popping that off, slice it to put the wire in the middle, then push it back into the hole, then zip tie the plug to the hitch or nearby. The Curt plug has a protective cap, so shouldn't be much of an issue in the elements.

Same video I found. So, if I understand this right, punch the coat hanger from the engine bay into the passenger compartment, attach the hot wire, (probably with a liberal application of some black electrical tape), then pull it back out, hopefully bringing the hot wire with it. Right? Seem simple enough . . . as long as I can get to the nipple. How many tries did it take you to punch through?
 
#15 ·
I installed the Toyota factory hitch and wiring harness my self in my 2015 XLE. The rubber nipple is pretty thick and it will take quite a bit of force to puncture a hole through it.

BEWARE: Before you insert the coat hanger from the inside, make sure that you curve your coat hanger away from the main wire harness bundle or you may accidentally force the coat hanger into the wire harness. This could create a short in the main wire harness and give you all sorts of problems. I believe another member of this forum experienced this when a non Toyota garage technician attempted to push a coat hanger through the rubber nipple.
 
#19 ·
Finally got fed up and went into my local Toyota dealer. He ran the wiring harness battery cable through the firewall, attached to the battery, and cleaned up everything better than I would have expected. All this for about $20. Such a deal!

Now, I'm debating somehow getting the plug to be permanently outside the vehicle instead of having to open the hatch and pull the cable out of the spare tire well.
 
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