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Hi, I have Rav4 2012.
I am trying to tap LED footwell light wires to the fuse that controls the dashboard lights. Basically I want these LED footwell lights to turn on only at night whenever I turn on the dashboard lights.

I have been using the user manual as reference

I'm looking at it and I thought "TAIL" fuse controls the lights on the dashboard. So, i took out the "TAIL" fuse, tapped the LED lights and put it back in but LED didn't turn on.

Then I tried turning on the dashboard light while the fuse was taken out and the lights did go on. So, I'm guessing that is not the right fuse. Any ideas on which fuse I should be pulling out to tap the LED wires??

Thank you for the help in advance
 

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Discussion Starter #2
trav4.net/checking_and_replacing_fuses-227


this is the user manual I have been referring to

(add www in the front and html at the end) Forum is prohibiting me from posting links
 

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Basically I want these LED footwell lights to turn on only at night whenever I turn on the dashboard lights..
A somewhat confusing post......

First of all the dashboard is always illuminated, (at least the instrument panel is) so I assume you mean when the back-lighting to the various switches is turned on.

Since the back-lighting turns on whenever the taillights are turned on, connecting to the TAIL fuse is an obvious place to start. First thing to clarify is if your RAV already has LED foot well lights that you want to reconfigure to be on anytime the taillights are on, or are you adding new foot well lights? If you are rewiring existing LED's, where in the circuit did you disconnect them and then reconnect them to the TAIL fuse?

I'm looking at it and I thought "TAIL" fuse controls the lights on the dashboard. So, i took out the "TAIL" fuse, tapped the LED lights and put it back in but LED didn't turn on.
The TAIL fuse should only be hot when the ECM is requesting the taillights to turn on. If your LED's didn't turn on when connected to the TAIL fuse you may have wired them with reverse polarity.

Then I tried turning on the dashboard light while the fuse was taken out and the lights did go on.
If the LED's worked with the TAIL fuse removed, then you probably connected to the "supply" side of the fuse and not the "load" side of the fuse, but if this was the case they should have worked with both the fuse plugged in or the fuse removed.

A simpler technique would be to connect you LEDs to the illumination wire at the rear of one of the back-lit switches. I think these circuits are already running at a reduced voltage so a dropping resistor would not be required.

BTW I couldn't get you link to display any wiring diagrams even when following your instructions.
 

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Discussion Starter #4
A somewhat confusing post......

First of all the dashboard is always illuminated, (at least the instrument panel is) so I assume you mean when the back-lighting to the various switches is turned on.

Since the back-lighting turns on whenever the taillights are turned on, connecting to the TAIL fuse is an obvious place to start. First thing to clarify is if your RAV already has LED foot well lights that you want to reconfigure to be on anytime the taillights are on, or are you adding new foot well lights? If you are rewiring existing LED's, where in the circuit did you disconnect them and then reconnect them to the TAIL fuse?



The TAIL fuse should only be hot when the ECM is requesting the taillights to turn on. If your LED's didn't turn on when connected to the TAIL fuse you may have wired them with reverse polarity.



If the LED's worked with the TAIL fuse removed, then you probably connected to the "supply" side of the fuse and not the "load" side of the fuse, but if this was the case they should have worked with both the fuse plugged in or the fuse removed.

A simpler technique would be to connect you LEDs to the illumination wire at the rear of one of the back-lit switches. I think these circuits are already running at a reduced voltage so a dropping resistor would not be required.

BTW I couldn't get you link to display any wiring diagrams even when following your instructions.

Firstly, I really appreciate you for taking your time to reply
As you can tell, I am a complete newbie at this.

1. I guess I should have said I want LED footwells to light up only when I turn on the taillights at night
2. I am adding NEW footwell lights
3. I meant to say my taillights (not LEDs) turned on while the "TAIL" fuse was pulled-out. Is this normal???????? I didn't think it was normal and I thought maybe I pulled-out wrong fuse.


I am planning on trying again tomorrow to "TAIL" fuse. If it does not work, I guess i'll try "GAUGE" fuse or "PANEL" fuse to see if I can accomplish my original goal.
 

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1. I guess I should have said I want LED footwells to light up only when I turn on the taillights at night
2. I am adding NEW footwell lights
3. I meant to say my taillights (not LEDs) turned on while the "TAIL" fuse was pulled-out. Is this normal???????? I didn't think it was normal and I thought maybe I pulled-out wrong fuse.
Either the 10A Tail fuse (red) or the 7.5A Panel fuse (brown) will provide power whenever the taillights are on.

Also removing the TAIL fuse should prevent the taillights from illuminating, so you probably removed the wrong fuse. The fuse panel is often difficult to relate with the drawing, especially when you are laying upside down. Perhaps knowing that it is a RED colored fuse may help to locate it. The owners manual shows that the fuse panel contains 7 10A (RED) fuses. The one you want is the only RED fuse at the end of a row. It is the one closest to the relays.

Also a reminder that LED's are sensitive to polarity. If you reverse the power and ground connections they will not work. Also remember that LED's work at voltages as low as 1 volt. If your LED's are not specifically made for a 12v circuit, you will have to add a dropping resistor to bring the 12 volts down to a safe working voltage.

Once you locate the TAIL fuse (when the taillights no longer work with the fuse pulled), measure both of the fuse contacts with a voltmeter before putting the fuse back in. Only one side will read 12 volts. Wire your LED's to the side that DOES NOT read 12 volts.
 

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Discussion Starter #6
Either the 10A Tail fuse (red) or the 7.5A Panel fuse (brown) will provide power whenever the taillights are on.

Also removing the TAIL fuse should prevent the taillights from illuminating, so you probably removed the wrong fuse. The fuse panel is often difficult to relate with the drawing, especially when you are laying upside down. Perhaps knowing that it is a RED colored fuse may help to locate it. The owners manual shows that the fuse panel contains 7 10A (RED) fuses. The one you want is the only RED fuse at the end of a row. It is the one closest to the relays.

Also a reminder that LED's are sensitive to polarity. If you reverse the power and ground connections they will not work. Also remember that LED's work at voltages as low as 1 volt. If your LED's are not specifically made for a 12v circuit, you will have to add a dropping resistor to bring the 12 volts down to a safe working voltage.

Once you locate the TAIL fuse (when the taillights no longer work with the fuse pulled), measure both of the fuse contacts with a voltmeter before putting the fuse back in. Only one side will read 12 volts. Wire your LED's to the side that DOES NOT read 12 volts.
So, I just wanted to let you know I got everything worked out. I tapped into "TAIL" fuse and its working fine now but there are a few things that still give me worries:

1. I bought the LEDs from Ebay which came without proper packaging, instructions or any information about the LED lights. Thus, I am not sure if those lights are made for 12v circuit. Description on Ebay unofficially said it is for 12v circuit but who knows right??? so if these lights are not made for 12v circuit, what risks am I taking by using them without adding a dropping resistor??? (I've been using this light without a problem for 1 day so far if that matters at all)

2. I used one of those piggy back "add-a-circuit-fuse" to tap into "TAIL" fuse. I inserted original 10A red fuse on the primary slot and 7.5A fuse on the seconday slot of the fuseholder. Did I do this correctly???

Again, thank you for helping this newbie.
 

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unofficially said it is for 12v circuit but who knows right??? so if these lights are not made for 12v circuit, what risks am I taking by using them without adding a dropping resistor???
If the description said they were for a 12 volt circuit, then the dropping resistor is probably already integrated into the LED or the harness. The LED's will fail prematurely if there is not a dropping resistor. In a 12 volt circuit that would probably have happened already if it was going to.

I inserted original 10A red fuse on the primary slot and 7.5A fuse on the seconday slot of the fuseholder. Did I do this correctly???
The LED's should use much less than 1 amp, so use the smallest fuse that you can locate within that size category of fuse. You can leave in the 7.5 amp fuse that you already have without much risk.
 

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If the description said they were for a 12 volt circuit, then the dropping resistor is probably already integrated into the LED or the harness. The LED's will fail prematurely if there is not a dropping resistor. In a 12 volt circuit that would probably have happened already if it was going to.



The LED's should use much less than 1 amp, so use the smallest fuse that you can locate within that size category of fuse. You can leave in the 7.5 amp fuse that you already have without much risk.
1. You said "You can leave in the 7.5 amp fuse that you already have without much risk" "Much risk" still kind of makes me get worried. So, its better to switch to smaller fuse? I do have 2.5A one. I thought it doesn't really matter as long as the amp value of the fuse is higher than the amount of amp used by LEDs.

2. Now, I would like to place same 12v LED lights on the exterior (behind the grill to be specific) and am planning to tap the fuse into the fuse box that's in the engine compartment. Specifically, I am planning to tap into "H-LP LH-LO" (Left hand headlight low beam) fuse. Again, I will be using piggy back "Add-a-fuse." Do you see any problem in that?? I'm just being extra careful because i feel like tapping into the fuse box in engine compartment should be done with more caution.

I really appreciate your help
 

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1. You said "You can leave in the 7.5 amp fuse that you already have without much risk" "Much risk" still kind of makes me get worried.
OPTION #1
If you added your new fuse to the supply side of the existing fuse, then the circuit could possibly be loaded to 10A (through the original fuse) plus the 7.5A (through the new fuse) for a total of 17.5A in a circuit designed to carry 10A.

OPTION #2
If you connected your new fuse to the load side of the existing 10A fuse (as I suggested in an earlier post), then the sum of current through both fuses cannot exceed 10A at which time the original fuse will blow.

So if you wired up things like OPTION #1, then I would use a smaller fuse to prevent the sum of the currents from reaching damaging levels, or simply choose OPTION #2.

So, its better to switch to smaller fuse? I do have 2.5A one.I thought it doesn't really matter as long as the amp value of the fuse is higher than the amount of amp used by LEDs.
I like to consider a blown fuse as an early indicator of a problem that may get worse. So sure, you could put in a 30A fuse to supply your 1A LED, and it will work. But if a problem occurs with a component and the current increases from 1A to 5A, you will not be aware of the impending failure with the 30A fuse. A component that fails in this manner could get quite hot and cause a fire.

NOTE: An individual LED can use as little as 20ma (.02A). As you add more LED's in the circuit, the current required will increase. I am using 1A as a general rule of thumb for the maximum you should ever require.


2. Now, I would like to place same 12v LED lights on the exterior (behind the grill to be specific) and am planning to tap the fuse into the fuse box that's in the engine compartment. Specifically, I am planning to tap into "H-LP LH-LO" (Left hand headlight low beam) fuse.
I can't find any fuses labelled as such in my copy of the wiring diagrams (although I show fuses with similar names and function). Yes that will work, but I would only use this method if you can properly close the cover on these fuse boxes due to the exposure to water.
 

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Just thought of another reason to consider when choosing the value of your add-on fuse, and how/where to connect it.

If you did wire your fuse according to OPTION #2 then .....
If the taillights use 7.5A (just a guess based on the 10A value of the fuse and allowing a safety factor) then if your foot-well lighting uses over 2.5A during a malfunction, then your 10A fuse will blow and kill your taillights.

Driving without taillights is a high risk to pay for the luxury of foot-well lights. You run the same risk of losing your headlights in order to have grill-lights.

You may be better off connecting your add-on fuse to the supply side of the original fuse (OPTION #1), and choosing a very small value for the add-on fuse so that the combined currents will not damage the wiring.
 
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