Toyota Prius Forum banner

1 - 20 of 22 Posts

·
Registered
Joined
·
15 Posts
Discussion Starter #1
Fog lights only on with full headlights are totally useless. Is there a fix existing where I could power the fog lights with the parking lights?

Second topic. I discovered I could, while driving, change my NAV destination by entering any of the six registered destination points. It won't allow you to go to the second page while driving. I am aware of Coastal's fix and am patiently awaiting delivery.
Serge
 

·
Registered
Joined
·
7,161 Posts
There is extensive discussion on PriusChat about this. You can put a diode between pins 17 (yellow) and 13 (sky blue) on connector B5 going to the body ECU in the driver J/B. The diode is needed rather than just a jumper, as otherwise you will create a latch condition when the body ECU sends a ground to the fog relay coil, it will also unwittingly send the ground to the fog switch input. This will allow the auto off to still function, though you will at least have to have your taillights on.
 

·
Registered
Joined
·
42 Posts
DanMan32 said:
There is extensive discussion on PriusChat about this. You can put a diode between pins 17 (yellow) and 13 (sky blue) on connector B5 going to the body ECU in the driver J/B. The diode is needed rather than just a jumper, as otherwise you will create a latch condition when the body ECU sends a ground to the fog relay coil, it will also unwittingly send the ground to the fog switch input. This will allow the auto off to still function, though you will at least have to have your taillights on.
Sorry Dan, I am sure it's my fault and/or impatience, but could you send me a link to a TechDesc on how to do this, please?
( I only spent ~20 minutes on priuschat searching while working on some other stuff, I confess )

Thanks,
Attila
 

·
Registered
Joined
·
42 Posts
bobc said:
Here's the link to the discussion and details on priuschat:

http://www.priuschat.com/forums/fog-lights-vt6525.html
Oh, thank you.

So, Dan, just to summarize :
1. No cutting of any wires is needed.
2. Put a diode in, where cathode goes to pin 13, and the anode to pin 17.

About this diode, what kinda nominal zener voltage and surge current you might be proposing? :lol:

Attila
 

·
Registered
Joined
·
7,161 Posts
Not a zener diode. A small rectifier diode will do, maybe .5A should be plenty. All you are doing is operating a relay coil. Also the wires to the combination switch are pretty tiny, I doubt they could carry any appreciable current, and others have operated the fog relay directly.

No cutting necessary, if you can get both leads of the diode make contact with their respective connector from the back side.

I'll be honest, I haven't done this yet, so I have not taken into account for the physical feasability, only the electrical feasability.
 

·
Registered
Joined
·
42 Posts
DanMan32 said:
Not a zener diode. A small rectifier diode will do, maybe .5A should be plenty. All you are doing is operating a relay coil. Also the wires to the combination switch are pretty tiny, I doubt they could carry any appreciable current, and others have operated the fog relay directly.

No cutting necessary, if you can get both leads of the diode make contact with their respective connector from the back side.

I'll be honest, I haven't done this yet, so I have not taken into account for the physical feasability, only the electrical feasability.
Tried for a while to "plug" a diode in, no luck.
Decided to do it the "less time consuming" way... Works great!

http://www.vassfamily.net/ToyotaPrius/F ... ogMod.html

Thanks,
Attila
 

·
Registered
Joined
·
7,161 Posts
Yes, that would work too. I was trying for the least invasive idea; IE not having to tap into wires. However, tapping would work just the same.
 

·
Registered
Joined
·
1,434 Posts
Yikes Attila!! Glad that worked for you, but I'd much prefer the 'shove a diode' technique if that could be worked out without disassembling the entire dash! Got the willies seeing all those connectors unplugged.

I think I'll wait for an idiot proof mod on this one.
 

·
Premium Member
Joined
·
2,815 Posts
KMO said:
Here it's illegal to turn on foglights unless you have <100m visibility, thank goodness.
My understanding is that the US and the UK have different definitions of fog lights. In the US, the factory ones on the Prius are small, white lights that are in the front bumper (low to the ground). My understanding is that in the UK, the fog light(s) are in the rear bumper...
 

·
Registered
Joined
·
42 Posts
KMO said:
Here it's illegal to turn on foglights unless you have <100m visibility, thank goodness.
I don't quite get the "thank goodness" part, but your foglights might be different than here than. They are most certainly less powerful ( and cheaper to replace ) than the HID lights. So having them turned on vs. the HID is actually not a bad thing...
 

·
Registered
Joined
·
1,233 Posts
mrv, you're referring to the rear foglight which is a single (occasionally dual) bright red light in the rear. It may or may not be in the bumper.

Some front foglights are bright, some aren't so we can't jump to a conclusion that all foglights are bad
 

·
Registered
Joined
·
42 Posts
efusco said:
Yikes Attila!! Glad that worked for you, but I'd much prefer the 'shove a diode' technique if that could be worked out without disassembling the entire dash! Got the willies seeing all those connectors unplugged.

I think I'll wait for an idiot proof mod on this one.
I hear you. I spent about 2 hours trying to fit the diode without having the dash taken apart. I did several soldering options to strengthen the legs of the diode, I even shaved'em so that they may fit next to the present wires, I even soldered needles on'em etc...

The other problem is space of course. If I only had a hand and a body of a 2 year old for the time of this mod, I might have been able to do it, but again, shoving the diode in to B5 does not seem like an easy thing to do.

So, I think the best solution so far is the way 'totavi99' had it on priuschat...

Again, at least I confirmed that DanMan32's diode solution is not only feasible on paper, but it works in practice as well...

Attila
 

·
Registered
Joined
·
49 Posts
The problem with front foglights is glare. They're more of a problem for oncoming drivers than dipped headlights.

The first reason for this is that they're not aimed down as much. They're mounted lower, but the cut-off is nearer the horizontal. Thus beyond a distance of 150 feet or so, the foglamp beam is higher than the dipped beam. It's more likely to flash into someone's eyes as you crest a hill, go over bumps, etc.

The second is that the nearness to the road and the deliberate extra projection of light into the foreground increases the amount of reflective glare from a wet road surface - they'll reflect at a shallow angle up off the road into the face of oncoming drivers.

Finally, in the Prius's case, the foglamp reflectors are a lot smaller than the dipped headlamps, but they have nearly as much total output, meaning a more intense point of light to dazzle other drivers.

My usual reaction to drivers driving around with foglights on (either front or rear) is to full-beam and/or foglight them and hope they get the hint.
 

·
Registered
Joined
·
2,285 Posts
Properly aimed foglamps are not a problem to oncoming traffic. That said, most people mis-aim them, throwing the beam upwards to get noticed. This defeats the very purpose of foglamps, which is to send a sharply cut off beam along the road surface, well below the beam of regular headlamps.

The first foot or two above ground level typically has a higher temperature, which creates a less foggy zone that hugs the ground (the exception is the "tule fog" along the central valley in California, which forms right along the ground, rarely rising above 15-20 feet.)

The value of the foglamp is that it projects below the reflective fog, illuminating the road and any hazards on it, but not throwing much light up into the fog to be reflected back, blinding the driver. Aim them high, and this only ADDS to the reflection, making visibility worse.

While it is true that a wet surface reflects foglamps into oncoming drivers, the same is true for a dipped headlamp beam. However, the effect is usually minimized by the uneven road surface which breaks up the reflection, effectively diminishing the blinding effect.

HIDs are far worse than foglamps is this respect. The foglamps are so much dimmer than HIDs that I am inclinded to make the mod to employ them as DRLs and forget them in fog.

Flashing high beams at a driver who is using properly aimed foglamps is not only offensive, but it is dangerous since it may blind him and make him run into you!
 

·
Registered
Joined
·
42 Posts
KTPhil said:
HIDs are far worse than foglamps is this respect. The foglamps are so much dimmer than HIDs that I am inclinded to make the mod to employ them as DRLs and forget them in fog.
Indeed. After reading these comments, I actually took the time both during the day and at night and turned on the HID, walked away from the car to about 150 yrds, did the same with the foglight only. No question in my mind that the foglight ( again, the ones I have on MY Prius ) is not only not as bright as the HID, but a lot easier on the eye. "I walked in the shoes..."

KTPhil said:
Flashing high beams at a driver who is using properly aimed foglamps is not only offensive, but it is dangerous since it may blind him and make him run into you!
Amen to that.
___________
 

·
Registered
Joined
·
2,285 Posts
I love HIDs, with my poor night vision. In rain, too, it helps light up the crap in the road (and we had a LOT of that in this year of triple-normal rainfall). But they have to be maintained with good aim or they become a hazard to others. I would have liked the leveling adjustment non-USA models offer, just to keep them low.

I'm still not sure how the claimed "autolevel" feature works in response to a load in the rear.
 

·
Registered
Joined
·
7,161 Posts
Autoleveling:

when the level of the car front to back changes, due to extra weight in the back, the HIDs are aimed lower to compensate.

Normal car: -
Weighted car: \ (exaggerated of course)

The leveler senses the distance between the bottom of the car in the rear and the ground. When there's more weight in the back, the springs comress more, so there's less ground clearance.
 
1 - 20 of 22 Posts
Top