Fog Light Wiring Woes - What Did I Kill?

[yoyoyotrevo]

Tonight, I switched my spot lights in my bumper out with some HID converted PIAA 510 fogs that will actually be useful on the road. After about 4 hours of breaking more than I fixed, I finally managed to get the project all buttoned up. Go to check out the lights and one of the fog lights isnt on. No biggie, go flip the switch again to reignite the ballast. Now, one headlight isnt on. OK, flip the switch, the other headlight isnt on. Again, flip the switch, this time everything comes on for about 10 seconds then the one headlight and the radio turn off and the clock and climate control lights dim.

After a long bewildering process of this, I realize something is definitely wrong. To make this shorter I'll list how everything is wired and all the symptoms.

2000 V6 SR5

Wiring
-HID headlights running off relayed connection triggered by power from headlight socket(typical HID harness). Main relay power and ground at blue sea fuse block.
-Factory fogs with halogen bulbs. Ran through original factory wiring.
-PIAA fogs with HID conversion. Ran off of relay with main power and ground at blue sea fuse block, TRIGGERED BY RED WIRE TO FACTORY FOG LIGHT BULB.*

*I think this is where I messed up. The previous lights in there had the same connections through this relay, but it was triggered by a seperate switch. I wanted these to turn on with factory fogs. This is the only part of the wiring that changed with the new lights.

Symptoms
-With fog lights on and headlights off all is well and the 4 fog lights work properly.
-With fogs and heads on, either one fog light or one headlight wont fire up. If its a headlight, all center dash lights turn off along with the radio shortly after.
-With just headlights, both will ignite for about 10 seconds when one will flicker off along with the center dash lights. The radio turns off 5 seconds after.
-The clock is dim with headlights on or with the switch in the middle position with just the interior lights on. Otherwise it's fine.

Notable mods
-The fog lights are wired to work when the high beams are on.
-Daytime Running Lights have been disabled.

(I dont remember the name for these mods but I believe they are on the mod reference list.)

I'm sure youre all thinking I should just disconnect it, but I've already cut the trigger wire from the factory fogs and the problem with the headlights/radio persists. I desperately need your guys help as I prefer to have 2 headlights at night and a radio is always nice too. So, what did I do wrong?

Also, [MENTION=10169]TheDurk[/MENTION]

 

[StreetCreeper]

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[TheDurk]

Do the headlights work if you pull the PIAA fog relay? How about with both fog relays pulled?

 

[TheDurk]

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Nice. Can I get a t-shirt?

 

[Tucson4runner]

Did you possibly bump a ground wire out of place when you were working around the battery? I have a very similar setup with a set of HID PIAA lights and some led cubes as my fog setup. What I did was wire the 2 led cubes with a harness directly to the battery (fused and relayed of course) and I used the passenger side hot for my trigger. Then I did the same with the HID PIAA lights but I used the driver's side hot. This way all 4 turn on when I turn my fog light switch.

Sent from my SM-G930V using Tapatalk

 

[yoyoyotrevo]

Do the headlights work if you pull the PIAA fog relay? How about with both fog relays pulled?

I pulled the relay completely the other morning and amazingly the headlights have been working normally. I guess my question is what could have caused it? That relay has been in place for a couple of years and I havent had a problem until I used the hot wire from the fog lights to trigger it.

Did you possibly bump a ground wire out of place when you were working around the battery? I have a very similar setup with a set of HID PIAA lights and some led cubes as my fog setup. What I did was wire the 2 led cubes with a harness directly to the battery (fused and relayed of course) and I used the passenger side hot for my trigger. Then I did the same with the HID PIAA lights but I used the driver's side hot. This way all 4 turn on when I turn my fog light switch.

Sent from my SM-G930V using Tapatalk

I dont think I knocked one out, and I've got additional ground wires, but I'll check to make sure. I've got about 800 wires running around the battery so it's hard to keep track of them all. It sounds like you did exactly what I'm trying to do so I'm not sure whats going on. I'll go mess with it for a while until I either figure it out or burn it down. :noidea: :flamethrwoer2:

 

[TheDurk]

I pulled the relay completely the other morning and amazingly the headlights have been working normally. I guess my question is what could have caused it? That relay has been in place for a couple of years and I havent had a problem until I used the hot wire from the fog lights to trigger it.

I thought that would happen, that's why I asked the question (so not 'amazing'to me). You have a short between the coil side circuit and the contact side circuit on that fog relay. First, try a new relay and report back. Those things don't last forever, especially the Chinese crap they include with aftermarket harnesses.

If the problem returns with a new relay, undo your tap, see what happens then. If no issue, try triggering your relay directly from the battery. Is the switch for the PIAAs in the ground leg or the hot leg to the headlight or is there no switch at all? Also, is relay for the PIAA foglights on the ground leg or the hot leg for the PIAA fog light power? (This is why I hate troubleshooting aftermarket stuff over the internet--I really have little idea how stuff is wired. You might solve your problem just by making a careful diagram of how those PIAAs are connected, with colors and pin numbers.) It sure would be easier to troubleshoot.

Uhh, looking at the factory fog light circuit, where did you find a red wire to tap for a trigger? My EWD says it should be Purple.

Another question. You say:

-The fog lights are wired to work when the high beams are on

. Exactly how and where did you do this mod? Also, why? The last thing you want in the fog is high beams....

 

[IBallEngineer]

Nice. Can I get a t-shirt?

If you change the text to "El Durko", I'll buy two!

 

[yoyoyotrevo]

I thought that would happen, that's why I asked the question (so not 'amazing'to me). You have a short between the coil side circuit and the contact side circuit on that fog relay.

Oh I know youre lightyears ahead of me on electrical things which is why I pulled it. I reconnected everything and all is good now. Honestly I think I had the relay connected differently previously(I'm not positive but something seemed different when I hooked it back up), but I would have never thought of it because it had been working like that for so long.

Also, is relay for the PIAA foglights on the ground leg or the hot leg for the PIAA fog light power? (This is why I hate troubleshooting aftermarket stuff over the internet--I really have little idea how stuff is wired. You might solve your problem just by making a careful diagram of how those PIAAs are connected, with colors and pin numbers.) It sure would be easier to troubleshoot.

I always run my relays on the hot leg but I've never actually though about doing otherwise...is there an advantage to putting them on the ground leg?

I get that, I once rewired headlights from scratch on a friends IS300 because I had no idea what in the hell he had done in there. So I'd imagine its near impossible to figure it out on the internet after some idiot like me has gone all mad scientist on their truck.

Uhh, looking at the factory fog light circuit, where did you find a red wire to tap for a trigger? My EWD says it should be Purple.

Another question. You say: . Exactly how and where did you do this mod? Also, why? The last thing you want in the fog is high beams....

Ehh, it might have been faded/dirty and I didnt have much light. It definitely was one of the two wires to the fog light, though, and not the one with the stripe.

Here is where I found out how to do it. Naa I definitely dont wan to use the high beams in the fog but I like to have them on offroad for a little bit of extra lighting. This lets you keep them on or off with the high beams and also you can independently control them with just parking lights on.

 

[TheDurk]

Oh I know youre lightyears ahead of me on electrical things which is why I pulled it. I reconnected everything and all is good now. Honestly I think I had the relay connected differently previously(I'm not positive but something seemed different when I hooked it back up), but I would have never thought of it because it had been working like that for so long.

Hey, mistakes are easy. I ran miswired fogs for two years before I figured it out. Hella had switched wire colors on two pins on their supplied relay harness and really screwed me up.


I always run my relays on the hot leg but I've never actually though about doing otherwise...is there an advantage to putting them on the ground leg?

None, really. It works either way. I just asked because I foresaw further troubleshooting and I needed to know.

I get that, I once rewired headlights from scratch on a friends IS300 because I had no idea what in the hell he had done in there. So I'd imagine its near impossible to figure it out on the internet after some idiot like me has gone all mad scientist on their truck.



Ehh, it might have been faded/dirty and I didnt have much light. It definitely was one of the two wires to the fog light, though, and not the one with the stripe.

Here is where I found out how to do it. Naa I definitely dont wan to use the high beams in the fog but I like to have them on offroad for a little bit of extra lighting. This lets you keep them on or off with the high beams and also you can independently control them with just parking lights on.

My answers in bold.

Glad you got it sorted out.

 

[IBallEngineer]

Oh I know youre lightyears ahead of me on electrical things which is why I pulled it. I reconnected everything and all is good now. Honestly I think I had the relay connected differently previously(I'm not positive but something seemed different when I hooked it back up), but I would have never thought of it because it had been working like that for so long.



I always run my relays on the hot leg but I've never actually though about doing otherwise...is there an advantage to putting them on the ground leg?

I get that, I once rewired headlights from scratch on a friends IS300 because I had no idea what in the hell he had done in there. So I'd imagine its near impossible to figure it out on the internet after some idiot like me has gone all mad scientist on their truck.



Ehh, it might have been faded/dirty and I didnt have much light. It definitely was one of the two wires to the fog light, though, and not the one with the stripe.

The benefit to switching the relay on the ground side is two fold, although relatively minor.

1. You can run run smaller gage wire to the switch, not always important unless you are wiring 10 switches and need to feed 10 wires through a small hole in the firewall.

2. The switch virtually doesn't have to carry any current. Again this is not as critical with relays, but again, it makes the switch easier to wire, and can be wired with smaller wires.

 

[yoyoyotrevo]

Hey, mistakes are easy. I ran miswired fogs for two years before I figured it out. Hella had switched wire colors on two pins on their supplied relay harness and really screwed me up.

This is part of the reason I like to wire my own relays, so I know exactly whats going on. Although, after two years, it gets a little confusing when everything was ran with black wires.

The benefit to switching the relay on the ground side is two fold, although relatively minor.

Thanks for your help El Durko. Youve saved me a couple of times now.

1. You can run run smaller gage wire to the switch, not always important unless you are wiring 10 switches and need to feed 10 wires through a small hole in the firewall.

2. The switch virtually doesn't have to carry any current. Again this is not as critical with relays, but again, it makes the switch easier to wire, and can be wired with smaller wires.

Thats good to know. I'll proably be doing this next time just to save some money on the copper stuff.

 

[TheDurk]

The benefit to switching the relay on the ground side is two fold, although relatively minor.

1. You can run run smaller gage wire to the switch, not always important unless you are wiring 10 switches and need to feed 10 wires through a small hole in the firewall.

2. The switch virtually doesn't have to carry any current. Again this is not as critical with relays, but again, it makes the switch easier to wire, and can be wired with smaller wires.

You lost me. The current required is the same whether you put the switch on the ground side of the coil or on the hot side of the coil. The load is the same, the coil, and it doesn't matter which side the switch is on. The only real consideration is where you want to tap your coil power and where you want to put your switch and where the relay is. One way may be easier to wire among those three locations than the other way. The current and wire gauge required will be the same throughout the circuit--small.

 

[IBallEngineer]

You lost me. The current required is the same whether you put the switch on the ground side of the coil or on the hot side of the coil. The load is the same, the coil, and it doesn't matter which side the switch is on. The only real consideration is where you want to tap your coil power and where you want to put your switch and where the relay is. One way may be easier to wire among those three locations than the other way. The current and wire gauge required will be the same throughout the circuit--small.

Hats off El Durko

I need to learn a little to better explain this, to myself mostly. I have been guilty of spreading a myth regarding the current after a load. There are other reasons why it is better to switch ground, but there are arguments against it as well. Mostly in the AC world, and far removed from the issues at work in our little forum.

The common conception of the ground wire being smaller than the 12V supply I believe is rooted in the length of the ground generally being shorter, because of the chassis being a buss bar for all grounds. I have to rethink this in it's entirety.

I'm going to build a guitar!

:yo:

 

[TheDurk]

Hats off El Durko

I need to learn a little to better explain this, to myself mostly. I have been guilty of spreading a myth regarding the current after a load. There are other reasons why it is better to switch ground, but there are arguments against it as well. Mostly in the AC world, and far removed from the issues at work in our little forum.

The common conception of the ground wire being smaller than the 12V supply I believe is rooted in the length of the ground generally being shorter, because of the chassis being a buss bar for all grounds. I have to rethink this in it's entirety.

I'm going to build a guitar!

:yo:

Plus, the load and thus the wire requirement for a Bosch relay coil is so small anyway, that to say you are going smaller on the ground is sort of meaningless. You really are then in the category of how small do you want to use for physical strength purposes. Me, I won't go smaller than 14AWG for auto wiring no matter how small the load. Just too easy to break, especially at the terminals. BMWs are full of their metric equivalent of 18 AWG and they are always breaking if any stress happens. Cheap ass Germans.

I had never heard of the current being smaller after the load. I look forward to an explanation if you get there. I also don't see how AC has anything to do with it, because then there is no before or after as far as current--hot vs. neutral AC is way different than hot vs ground DC. As I recall, most house wiring will place switches on the hot leg, mainly so they can use a common neutral for more than one load.

Anyway, I'm sticking to my rule of use the switch on whichever leg lets you make the simplest, shortest circuit.