LED's to replace OEM lights - my experience so far

Here is my experience to date with replacing lightbulbs with LEDs for my 2012 plug in prius.

The LEDs
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I bought all of my LEDS on ebay. They are generally quite inexpensive. I like the '5050' based bulbs as they are generally bright, cheap, and low power.

2x T10 5-SMD 5050 LED White lights bulbs interior,door, license plate, parking | eBay

5 5050 leds, a nice socket that fits tightly, and small enough to fit many places.
Avoid the sockets that have one wire on each side, as they tent to fit loosely.
$2.49 for 2.

2x T10 9-SMD 5050 LED White lights bulbs interior,door, license plate, parking | eBay

9 5050 leds, same nice socket as above. Fits in less places than above.
$3.99 for 2.

2PCS T10 168 W5W 9 SMD White LED Wedge Signal Car Light | eBay

this is a 9 led array that has the all the leds perpendicular to the socket. Used for map light
$1.55 for 2.

27MM 31MM 36MM 39MM 42MM T10 BA9S 12-5050 SMD Warm white LED Festoon Dome bulbs | eBay

this is a 12 led panel with connectors for different bulb sockets. I picked warm white, which is close to the incandescent color. You can pick a higher temperature if you want it to match more closely with the rest of the LEDs.
$2.99 for 1.

2X T10 501 W5W 168 Pure White Car 4 LED 5050 SMD Side Light Lamp Bulb DC 12V New | eBay

A 4 led flat array. Works with AC or DC, so you can insert it in any orientation.
$2.49 for 2

Interior
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The vanity light uses a 8w 'wedge' which means a T10 base. I replaced mine with a the 9 led 5050 bulb. It was easy to remove the cover, and there is lots of room. All the light comes out of one side, so you might consider a flat LED array with all the LEDs on one side.

The map light uses a 5w 'wedge' T10 base bulb. It requires a smallish bulb, and you want all the light to come out the end. I used LED with 9 no-name leds. It has a slight pinkish glow, but works well. Easy to remove the cover.

Dome light uses a 8w festoon bulb, which means a bulb with a connector on each end. I think it is 31mm long. I used the 12 led panel. I put it behind the bulb socket so you can still access the socket. There are bigger arrays, up to 20 or 24 leds, but 12 is plenty bright. Needless to say, all the light comes out on one side.

See T10 BA9S 27MM 31MM 36MM 39MM 42MM 24-5050 SMD LED Warm white Festoon Dome bulbs | eBay for the 24 led array.

Trunk light uses a 5w 27mm festoon bulb. Easy to access.
I have ordered the 12 led array for the trunk light, and I will install it by gluing it to the inside of the lens. It fits fine and is tight enough to not require any glue to hold it in. The problem is the festoon adapter shorts out when compressed to 27mm. I ended up soldering the wires to the fixture. One end was easy to solder, but the switch end is unsolderable. I ended up wrapping some stranded copper wire around it, crimping it down, soldering it, and soldered the wire to it. The switch feels a bit different since there is no bulb in the fixture. I recommend a fixed 27mm adapter if such a thing exists. The 12 5050 LEDs are plenty bright. Like the dome light, all the light comes out on one side.

The step/courtesy light bulbs in the front doors are 5w T10. The way I accessed them was to pull off the door skins. Then they are easy to access. The 9 led 5050 is much too long to fit inside. If I ever pull the door skins off, I will try the 4 led flat array. All the light comes out on one side. I found the lights somewhat complex to disassemble. Turns out it is easy to take the light out without pulling the door skin.

Exterior
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The parking light bulb uses a 5w T10 base bulb. Easy to access. I used the 9 led 5050 bulb to replace mine. It does stick up a bit, but fits fine. You could also use the 5 led 5050 bulb.

Front side marker lights use a 5w t10 base bulb. If you are not careful, the bulb can fall out, and you will have to hunt for it. You will likely have to remove the black plastic parts on the bottom of the car. There are enough nooks and crannies that you may end up losing a bulb, like I did. Be very very careful not to drop the bulbs. This location is a bit tight. I ended up using a 5 led 5050 bulb. It is roughly as bright as the OEM bulb. If there was a decent amber 5050 bulb, that would be ideal, but I haven't found one yet.

License plate lights use a 5w T10 bulb. There is very little room here. Even the 5 led 5050 bulb hits the end and a shorter LED should be used. All of the light comes out of one side, pointed at the license plate. I ordered the 4 LED flat array, and after a small amount of trimming at the corner between the contacts and the main LED board, it installed and works fine.


Right now, I have replaced 14 bulbs in my car. The new LEDs are brighter and use less power than the bulbs. They will likely last forever. For the exterior lights, I have replaced six 5w bulbs, likely saving 20-25 watts. I don't know why Toyota didn't use more LEDs as they are so cheap. All the prices quoted include shipping from hong kong to the USA.

 

Front Turn Signal Light Bulb Size: WY21W 21w amber
Rear Turn Signal Light Bulb Size: WY21W 21w amber

According to GE Lighting - WY21W
these produce 280 lumens. Very good LEDs produce 100 lumens/watt. Cheaper ones are around 50 lumens/watt. So you would likely need 2.8-5.6 watts of LED to get similar brightness. Since a glass lamp is omnidirectional, but a LED is directional, you might get by with less lumens, though there is an inefficient reflector for the glass bulb.
The ebay bulbs often do not specify lumens, and when they do, their accuracy is suspect. In addition, the T10 base is not very robust when dealing with heavier bulbs than they were designed for. When you add it all up, the turn signal isn't the best bulb to replace with LEDs. They shouldn't be on very much, so you won't get a big win by replacing them. I think I will wait a year or so, for cheaper, more efficient LEDs. You should look for the 'cree' brand when dealing with bright bulbs, such as turn signals or backup lights.