Balancing Act

Next Prius project: Converting high-beams into daytime running lights (DRL)

UPDATE: DIY guide is now available: DIY: How to add daytime running lights to a 2010-2011 Prius

My next weekend project for the Prius is to convert the high-beams into daytime running lights (DRL), like older Toyotas and certain models, such as the Corolla. The idea is to install a module with built-in resistor to reduce the high-beam output by 60%, i.e. operating the high-beams at 40% of its full power. This DIY write-up is adapted from the same project conducted on my old Acura RSX, DIY: How to add daytime running lights (DRL) on your USDM Acura RSX. There is one difference between the Prius DRL project and the RSX project.

EDIT: The Hamsar 45060 compact DRL module, I believe, may have been discontinued by Hamsar. It’s not available for purchase from their online web store (but info on it still exists), however I was able to purchase the same 45060 module from the same distributor from where I purchased the original module for the RSX. The price increased by $10 in the span of 4 years. If you can’t locate a 45060 unit through a distributor, a newer model 45035 module can be used instead.

The main difference between this project and the RSX project is the DRL in the RSX were automatically controlled by the ignition wire, meaning if the car is turned on or the ignition is switched to position II  (i.e. Accessory), the lights turn on. In the Prius project, it will be wired up to a dedicated DRL push button switch that’s triggered by an ACC wire:

DRL Switch

DRL Switch

Since it is wired up to an illuminated switch, I diode-isolated the trigger wire on the  Hamsar 45060 module to prevent any unwanted electrical feedback, causing the button to illuminate even when the car is off.

With this switch, the high-beam converted DRL can be manually switched on or off, just like the OEM DRL on the 2012+ 3rd gen Prius models. The wiring is similar to wiring up a set of fog lights for the Prius with some minor differences. This mod is mainly cosmetic for 3rd gen 2012+ Prius models since these models already have built-in LED DRL from factory. If you do not use the factory DRLs, then this mod will serve its purpose as alternate, legal and functional DRL. If you own a 2010-2011 3rd gen Prius, then this mod allows you the opportunity to add safety features of DRL to you car.

Hamsar 45020 DRL module

Hamsar 45035 DRL module

The write-up will take longer than the actual install, so stay tuned. As with any DIY write-ups I write that involves modding the car’s wires, this will follow the same mantra, that no OEM wires will be cut and all modifications made is 100% reversible.

 

Digging through the cache of Honda and Acura parts from past projects, I’ve came across a treasure trove of wires, connectors, plugs and pigtails that can be used to facilitate a clean OEM-like installation on future mirror projects, such as power folding side mirrors, auto-tilt on reverse and combo puddle/signal/marker mirrors. The combo mirror install will be the next project I will pursue, followed by the auto-tilt on reverse mod; both mods are useful and functional to me and both mods will be utilizing spare Honda parts and connectors for a clean OEM-like install. The install will include part numbers of the Honda connectors and pigtails for reference.

Hamsar 45060 DRL module installed on a 2012 Prius; 60% reduced high beams

Hamsar 45060 DRL module installed on a 2012 Prius; 60% reduced high beams

Hamsar 45060 DRL module installed on a 2012 Prius; normal high beam mode

Hamsar 45060 DRL module installed on a 2012 Prius; normal high beam mode

The auto-tilt on reverse mod is more work than it sounds. For example, to install it per OEM instructions, you will need to remove half of the passenger side covers (i.e. glove box, lower glove box cover, side step cover) as well as the entire center console. Mounting the reverse tilting module is just half the work. And base on the instruction set, the module only tilts one mirror. I will write an extensive article on how modify the module so that those who wish to pursue this mod can wire it up so that it either tilts only one mirror or wire it up so that it tilts both mirrors.

I like to end this entry by noting that I’ve been receiving a handful of messages asking me when I’ll write-up a JDM power folding side mirror guide for the Prius. My answer is if you can find me a source where I can obtain a set for $600 or less, I’ll make the investment and do the write-up. At $800 brand new, not including the optional keyless entry auto-folding module, it’s a bit of a stretch in terms of priority. As cool as JDM power side folding mirrors are, I rather spend that $800 on a nice vacation or wine and dine my heart out with the lady.

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