Highbeam 50% DRL mod, completed

Edited 11/24/13 & 1/30/14: Great news for anyone interested in getting highbeam DRLs in their Prius... found a pair of relatively inexpensive, but looks to be well made solid state DRL modules on eBay:

The seller has two versions available:

Economy version (module only, 1 yr warranty), and better quality version (wiring harness and connectors included, 2yr warranty). Has all the functionality of my homemade one, even has delay for on/off. Major advantage to these modules over mine is that they are solid state with no moving parts to wear out (no mechanical relays), and they run the highbeam bulbs at 30% power. TBH, the module I made seems to have the highbeam bulbs burning a bit too brightly. At approximately 50%, they are definitely brighter than the factory highbeam DRLs in my Camry.

I am seriously considering getting one of these DRL modules from this seller and wiring it in our Prius to get a proper 30% highbeam DRL. I have installed the better quality version and it is running great. I highly recommend these modules. See post #43, page 3 for how I used 9005 harnesses purchased on eBay so the oem highbeam wires didn't need to be tapped with the connectors that pierce the insulation.

End of edit...

Original post:

Background: Toyota puts DRLs in almost all late model cars it sells in NA, except the Gen2 and Gen 3 (2010 - 2011) Prius. I feel that DRLs are an important safety feature, so the quest was on to equip our 2011 Prius with DRLs.

1) I tried using my OEM foglight kit with "high power" amber (more like orange) CREE 5w LEDs wired to come on in Ready Mode. However, the LEDs simply weren't bright enough to be visible in bright sunlight.

2) Then I modified some H8 35w yellow halogen bulbs (ground down a locking tab) to use as my foglight DRLs. The light output was good, and the lower wattage meant less heat in the small foglight housing during the hot daytime conditions. However, the foglights are mounted very low and slightly recessed into the lower bumper, limiting their visibility.

3) I came upon these threads in an Integra forum:

Dimming my high's into city lights...help - Team Integra Forums - Team Integra

and

High beams as DRL without losing high beams - Team Integra Forums - Team Integra

What this mod does is run the two 9005 halogen bulbs used for the high beams at reduced power (approximately half power) like almost all of the cars sold with oem DRL lights. It does this by switching from the normal parallel wiring (full power highbeam) to a series circuit (approximately half power).

However, it didn't seem as though anyone actually did the mod, or at least no one posted the results of such a mod.

So I dove head first into the deep end and came up with a modified highbeam DRL mod with some overrides to get as close to stock Toyota DRL functionality:



In diagram above, all red, purple and black wires in the circuit from the +12v power through the 9005 bulbs must be 14 gauge wire or lower. The black wires for grounding relay coils and all other control wires can be 18 gauge wire.

In the end, I only used 4 fuses in the fuse block I added into the DRL module (1 10A for driver's highbeam circuit, 1 10A for passenger's side highbeam circuit, 1 20A for power coming from engine fuse block, and 1 5A for the + highbeam control wire). The + Ready Mode input was taken from the passenger compartment fuse block using a fused tap from one of the seat heater circuits, and the parking/low beam + control wire came from a tap from under the dash (brown wire) that is already fused somewhere.

Gathered all the supplies and started to crimp and solder everything together. Came up with my first prototype DRL module:



The relays are on the left, and there is a fuse block on the right. Everything worked, but my coworker and neighbor thought that the clear storage container I put it in wouldn't please the Toyota techs the next time they serviced our Prius. So I bought a black ABS project box from Radio Shack and it morphed into this:



With the included black plastic cover, the "black box" DRL module, with wires covered up into wiring harnesses and 9005 sockets, the installation looks pretty much invisible. I fabricated a bracket and installed the DRL module in the space behind the driver's side foglight, in front of the wheel well. Note: If you look closely at the pic above, there is a third rubber grommet in the project box wall next to the relays. I put a pvc tube through there and ran it down the side of the box and secured it to provide "venting" of any humid air and possibly vent off any heat coming from the relays. The open end is pointing down to exclude any splashed water from getting into the enclosure.

Here's an earlier "bench test" on my Camry to show that using the module, the high beams can be switched from a parallel circuit (100% power) to a series circuit (50% power), and energizing the high beam trigger wire switches the 50% series circuit to the 100% parallel circuit.

Click on the image below for a video:



So now, the Prius has the high beams come on at 50% DRL power in Ready Mode. It can be turned off at a dash toggle switch at any time. The flash to pass highbeam mode works just like OEM, and turning the parking lights/lowbeam headlights on turns off the DRLs.

Also, when the lowbeams are on, the highbeams can still be flashed or activated via the OEM multifunction light switch on the stalk. The only thing this doesn't have compared to the OEM DRLs on my Camry is the parking brake switch override. My Camry's DRLs will not come on when in Park, but switch on when the parking brake is released and the transmission put into drive.

Edit (1/9/13): Here is a very short video of the install in the Prius which shows the following functionality (Off, DRLs on, Flash to pass highbeams, parking lights on/DRLs off, headlights on/DRLs off, flash to pass highbeams with headlights on, highbeam switch on, lowbeams, parking lights, DRLs, off).

Click on image for video:




(Added 01/18/13) High beam DRLs with the golden yellow 55w 9005 bulbs, discussed in post #12 below, at half power. No orange color like regular 9005 bulbs:



Edit 01/21/13: Here's a shot in full sun:



Disclaimer: If you decide to try this, I am in no way responsible for any damage to your vehicle, nor any voiding of warranties or denial of service from Toyota or anyone else.

If anyone is going to do this mod, here are some links to some hard to find parts and some installation notes:

Link for the 9005 headlight terminals (pins/sockets that go in the 9005 connectors), can also buy the 9005 headlight socket shells here. You will need 2 female plugs and 1 male plug, 4 female 9005 socket terminals and 2 male 9005 pin terminals, they're cheap so buy extras:

Automotive Connectors

This is a good site with split wire loom, crimp on terminals, heat shrink tubing, and relays (bought DPDT relays from Radioshack, catalog #275-0218). Wish I had seen this site before I purchased all my stuff. Wiring loom in 1/4" and 3/8" or 1/2" is what you want. I used a 1/2" split loom to encase my DRL wires along with my OEM foglight wires going to the passenger side for a clean one harness installation.:

Sherco Auto Supply

And finally, some notes: (refer to following picture, click on image for larger image)



In the picture above: The upper left side of the picture shows the red +12v power wire with a female spade type terminal which I connected to an open terminal in the engine fuse box. It also shows the black ground wire for the highbeam circuit, it is terminated with a ring terminal. I bolted it to the car along with my mounting bracket. The lower left harness shows a white and green control wires for +12v Ready Mode and +12v lowbeam/parking light. It also shows a trailer light connector that I used so that I could disconnect the control wires in the future without cutting wires. The upper right harness has the driver's side 9005 female connector and a 9005 male connector. The 9005 male connector will plug into the oem 9005 female connector that came off the driver's side highbeam bulb, it serves as the ground for the relays and the + wire for the highbeam control wire. The lower right harness goes to the passenger side 9005 highbeam bulb. The original 9005 female connector that you unplug from the bulb will be unused on the passenger side.

Here's a pic that shows the power lead connected to an open terminal in the engine fuse block. The other smaller red lead in the image is for my OEM foglights:



1) Cut the wires going to the driver's side 9005 female and male connectors to 2 ft. in length.

2) Cut the wires going to the passenger side 9005 female connector to 7.5 ft., I did it with 7 ft. but it just made it.

3) It's easiest to ground all the relays together and run one ground wire out to the male 9005 plug (the one that was originally connected to the driver's side 9005 bulb) and use that ground wire for ground. The other wire in that plug will be one of your control wires for the circuit (highbeam +).

4) If you are going to install an override switch in the dash, you're going to have to run 2 wires through the firewall. If you've installed the factory OEM style foglights, then you know what grommet to do this through.

5) You have a choice for the lowbeam + control, use either a tap off the lowbeam headlight + wire, or a tap off the brown wire under the dash for the parking/lowbeam control circuit (again, if you've installed the OEM foglights you know what/where this is). Using the brown under dash wire will require running a wire through the firewall.

 

Thanks, Sean.

I'm sure most ppl here would say something like, "congratulations, dude, you just made your Prius look like every other car out there."

But that was my goal all along.

 

I read somewhere that blue bulbs give a "muddy pool" color when used at low power, which I find entirely plausible since the 9005 when used at lower wattage becomes more orange in light output. So orange + blue = ??? burnt orange lol.

 

Something interesting I noticed is that the 9005 bulbs on my Camry have a slight orangish coating on them at the tip and base of the bulb. It isn't opaque, but a semi translucent coating:



The 9005 bulbs in the Prius and all the other bulbs in the store do not have this type of coating. I'm not sure if this coating is intended to make the DRLs appear even more orange when burned at lower wattage or not, but that seems to be the case.

 

OP updated to show DRL and highbeam function on our Prius. Click on the video link (Prius image) in the middle section of first post.

 

OP updated with some links for hard to find parts and installation notes. Assuming you mount the DRL module in the same location I used, the space in front of the driver's side front wheel well behind the driver's side foglight/blank, the DRL module will be pretty much hidden below the driver's side headlight housing and wiring harnesses.

 

Not sure, but the non coated ones in the Prius seem brighter when burning at DRL power. Since I couldn't find any 9005 bulbs with similar coating for the Prius I have some 55w halogen 9005 "golden yellow" bulbs coming in from China lol. They are clear with some kind of translucent coating that look similar to the Camry's 9005 bulbs. I'm hoping the slightly lower wattage plus the coating makes the Prius DRLs more like those on the Camry.

Here's a link to the bulbs :

2pcs 9005 HB3 Vehicle Car Headlamp Light Bulb Gold Yellow DC 12V 55W Halogen Kit | eBay

 

Found what looks like the same "Gold Yellow" 9005 bulbs from Hong Kong on Amazon for less:

Amazon.com: Po 2pcs 9005 Hb3 Auto Light Bulb Lamp Gold Yellow Dc 12v 55w Halogen Xenonfor Home: Home Improvement

I am hoping to receive the ones I ordered off eBay this Saturday or Monday. I will update with my impressions.

 

Thanks rrg.

Yeah, I guess Toyota was trying to squeeze every last mpg out of the Prius. After installation of the DRL module on 12/29/12, I haven't seen any noticeable drop in mpg. Will continue to monitor mpg in Fuelly.

AFAIK, the Camry Hybrid has DRLs, so I guess it was just a decision the Toyota engineers made when spec'ing the Prius.

 

Installed the bulbs I received from the eBay seller today. They look good. , pretty much clear when off, and when at DRL power, they are more yellow than orange, which is what I wanted. At high beam full power, the bulbs give off a medium yellow light.

Installed in my Camry so far, will post pics of them in the Prius later this week. I will try to remember to take pics with one side oem and one side with these "golden yellow" 9005 bulbs installed.

Update 1/16/13: I had the bulbs out of my Camry today and could see that they are already discolored with what appears to be carbon or soot. None of the other oem or aftermarket bulbs I've ever used have done this. It does not bode well for these cheap Chinese bulbs. It's a shame, cause they look great.

Update 1/245/13: Took the golden yellow 9005 bulbs out of my Camry (saving them for the Prius), they definitely have carbon or soot residue in the bulbs, coating the inside of the bulbs near the filaments. I highly suspect that there is no inert halogen gas inside these bulbs. No wonder they are so inexpensive. I have placed the oem clear 9005 bulbs from the Prius into my Camry. I'm saving the orange coated ones from my Camry for use in the Prius, when these cheap "golden yellow" bulbs fail, which from the looks of it, will be fairly soon.

 

jzchen, sorry, no plans to build and sell any DRL modules.

I'm not familiar with the system you refer to but there is one by web electric that uses the front amber turn signal bulbs for DRLs.

 

Did a search for the Hamsar DRL module you referred to and found this blog from Steve Khou, who is incidentally on this PriusChat forums as well.

Link

Looks like a simpler method to get the same functionality as my mod in a smaller, easier to install module (2 relays vs 4) since the Hamsar module is solid state and compact.

One thing I noticed that was incorrect in the blog though, is that the Hamsar DRL module outputs 40% power to the high beam bulbs (60% reduced power, not 60% power) which is actually better than 60%, which would be too bright. Anyone who wants DRLs in their Prius should consider going the Hamsar route.

 

Also added this pic to OP above. This shot of the DRLs are with the "golden yellow" 55w 9005 purchased on eBay. Link in post #12 above:



Note there is no orange color to the highbeam 9005 bulbs run at half power like there would normally be with a clear bulb operated at low power. The other benefit to this bulb is that the coating used to achieve the yellow output does not make the bulb and the reflector "yellow". The bulb has a very slight iridescent or "rainbow" metallic(?) coating on it, similar I guess to PIAA bulbs with the plasma ion coating that burn intense yellow. These bulbs don't have as intense a yellow color as the PIAAs though, even when burning at full power.