Diode Dynamics HP3 and SM5 LED bulbs side by side

Diode Dynamics HP3 vs SMD5 LED bulb comparison and review

I’ve been a fan of Diode Dynamics‘ LED bulbs ever since I replaced all my Subaru BRZ‘s bulbs with LEDs. They have excellent customer service and they stand behind their products with a great three year warranty. They recently introduced a couple new LED bulb to their line up, the HP3 and HP5. The HP3 and HP5 are replacement bulbs for 194 sized sockets. They work for anything from your trunk, door and sidemarker lights around your vehicle.

Diode Dynamics HP3 vs SM5 side by side
Left: Amber HP3 | Right: Amber SMD5

Before these bulbs were introduced, the brightest bulb you could get were the SMD5s, which featured five LEDs placed around the bulb. They worked well but the HP3s are slightly brighter and offer a deeper color. Take a look below at the old SMD5 bulb.

Diode Dynamics SM5 amber sidemarker
The old SMD5 amber LED bulbs

Versus the new HP3 amber bulbs.

The new HP3 amber LED bulbs

As you can see, the new HP3 bulbs are not only brighter but put out a deeper orange color, perfect for staying visible at night. The HP3 bulbs are designed to disperse light more evenly and stay cooler during extended use.

The best thing about the HP3 bulbs is that they are non-polarity bulbs, meaning you can install them any way. The old SMD5 bulbs required me to test that they turn on before I finalized installation.

One thing to note if you’re using replacing your incandescent sidemarker bulbs for your Subaru BRZ or FR-S is that the LED contacts are just a bit too narrow for the sidemarker socket. I recommend bending the contacts outward just a little to make sure they have good contact with the terminals.

I’ve been using the HP3 bulbs for over a week now and they look so much better than the SMD5 bulbs. I haven’t had either sidemarker bulbs fail or any flickering issues. Highly recommended.

2 thoughts on “Diode Dynamics HP3 vs SMD5 LED bulb comparison and review”

  1. Terrific presentation on your website, Lewis!

    I also have a BRZ (2014 Limited) and am just beginning to replace certain bulbs with LEDs. The HP3 sidemarkers are going in new smoke gray lenses (all the better blend with the sterling silver metallic paint).

    I know you must have slogged through the forest of available replacements, as I’m beginning to do. I’ d love to know what bulbs you chose, to inform my own choices, if you wouldn’t think me over-the-top rude to ask you to hand over all your work.

    Anyway, I’m going for pretty much “normal” lighting, e.g. an interior map light which doesn’t give me a sunburn like in Close Encounters, turn signals that don’t give other drivers spots before their eyes, and fog lights in real yellow to cut through real fog, without looking like a night game at the stadium.

    Best of wishes to you for 2016.


    1. Hi, David.

      I’m a huge fan of Diode Dynamics so I’ll stick with them. They offer their interior lights in a variety of brightnesses so choose the one that suits you. I have the warm white SMD12 board for the dome and I don’t think it’s too bright. It’s definitely way brighter than the stock bulb but it’s handy for finding things at night.

      For vanity lights, I have the warm white SMF1 bulb, which I don’t think is too bright.

      Diode Dynamics may be more expensive than the generic bulbs you find on eBay but I’d happily pay the premium for great customer service. I’ve had a few bulbs go out and Diode Dynamics always takes care of me.


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