Caution regarding Prius Gen 3 Foglight Retrofit Kits

Caution - Be Aware Of These Issues, Even If You've Already Installed This Foglight Kit (PIPL-40C)
Fog Light Kit for 2010-2011 Toyota Prius - OEM Quality - PriusChat Shop $114.99

IF YOU HAVE ONE OF THESE FOGLIGHT KITS, YOU NEED TO CHECK THAT YOUR 12Vdc RELAY IS SECURELY MOUNTED WITH THE MOUNTING TAB ORIENTED UP. CONFIRM THAT THE RELAY CONTACTS ARE DRY AND FREE OF CORROSION AND RUST. IF THEY AREN'T, REPLACE THE RELAY (IT'S LIKELY TO FAIL SOON).

ON NEW KIT INSTALLATIONS, THE RELAY SHOULD BE MOUNTED SECURELY, ORIENTED WITH THE MOUNTING TAB ON TOP, AND MAKE THE CONNECTORS AND CASE AS WATERPROOF AS POSSIBLE (I RECOMMEND LIBERAL APPLICATION OF CLEAR SILICONE SEALANT).

Back in May 2014, I ordered one of the Fog Light Kits for 2010-2011 Toyota Prius (PIPL-40C) sold for $114.99 in the PriusChat Accessories Store. I had the kit installed in our 2010 Prius III by our local Toyota dealership (it took some convincing), and the foglights worked fine for over 2 years, then died. I assumed the H-11 bulbs had both burned out, but it turned out that the 12Vdc relay was completely shot from rust and corrosion. I want to warn others so they can avoid this problem.

The electrical relay that's included with these kits IS NOT WATERPROOF and can fill with water, then corrode and rust, possibly causing an electrical fire if you're unlucky. The relay must be mounted inside the engine compartment near the fusebox with the mounting tab on top and vertical. Even better if you can enclose the base of the relay housing and the wiring harness socket with clear silicone to waterproof them.

While troubleshooting our dead foglights, I discovered that the 4 relay connector pins and the corresponding wiring harness sockets were all corroded and rusty. When I curiously pried open the relay housing, the black plastic case was nearly filled with moist rust and corrosion. The relay had apparently been oriented "upside down" and water must have gotten inside when the engine compartment was cleaned with a pressure washer.

The relay included in our kit was a CHUN-1 Automotive Relay 388-A-12V-S 12Vdc/40A. This is a standard automotive relay made by several companies, replace it with a well-made equivalent 40A rated relay, be wary of cheap relays rated "30A-40A" I found a couple online priced around $6.

The 2010-2011 Prius fog lights use OSRAM H-11 bulbs, the same type bulbs as the Prius low beams. There are now more efficient LED "H-11 bulb" replacements available at reasonable prices that don't get nearly as hot and last much longer than traditional halogen bulbs, they can also be used for the low beams (always replace these bulbs as a set of 2).

LEDs that are 4700K-5000K (degrees Kelvin) are very white like full daylight ("cool white"), 6000K and higher is a harsh bluish-white, 3200K-4500K is more like standard incandescent bulbs with a hint of yellow/red ("warm white"). The lower the temperature below 4500K, the "redder" the LED's light. Standard halogen bulbs range from around 3200K (OSRAM standard) to 4300K (Philips WhiteVision), bulbs with a halogen/xenon mix are higher/whiter. I personally think that 6000K+ "blue" headlights and foglights are obnoxious and dangerous, many states limit or ban them, they are harsh and hinder your night vision.

 

This is the foglight retrofit kit (still listed at $114.99):
Fog Light Kit for 2010-2011 Toyota Prius - OEM Quality - PriusChat Shop

 

Doh! I completely missed those discussion threads ... I hope I haven't mislead any forum readers/members.
I don't have time to carefully research this right now, sorry.
What's the current/power rating on the IPJB foglight relay of your reminder?
Is that a primary relay used to drive the two OEM foglights directly, or is it a secondary relay that - in turn - drives a high-amperage (40A) primary relay in the engine compartment that in turn powers the foglights?
Despite being an electrical engineer, I didn't install the retrofit kit myself, but it has an OEM dashboard switch with integral green LED indicator, and the foglights are disabled unless the low beam headlights are on (same as the OEM foglights), so I'm guessing that the kit utilizes the inside relay and any other components present in a non-foglight 2010-2011 Prius. Am I mistaken?
On a related topic, have any forum members tried substituting "H-11 bulb" replacement LEDs for their fog light bulbs or their low beam bulbs? I realize that the newer Prius models have a cluster of foglight LEDs, that's not what I'm asking about.
Thanks for your patience. dc

 

The foglights retrofit kit (link above) provides its own 40A relay that ends up in the engine compartment near the fusebox, that's why mine eventually got wet and rusted/corroded, and why I posted the warning. Apparently the kit makers weren't aware of the standard interior foglight relay or weren't confident that it would be present in all the 2010/2011 Prius that were sold without factory foglights. Thanks again for pointing this out.