PIAA Fog lamp Wiring.

[Darkbloodmon]

If it includes its own relay, then that's the way to go. According to the web page it comes with a relay AND a switch. You most likely can wire it up still to use the stock switch even if the included instructions don't show you that option.

However, if you want to be able to turn the fogs separate from the spots, you might want additional switches.

Got both light sets today, they came with a very generous and well made wiring harness(with relay and switch) but the instruction manual is leaving a lot to be desired.

Instruction manual says 3amp max for the inline fuse on the harness, I check both harnesses and I'm looking at a 30amp. The harness doesn't have a wiring diagram either so I'll have to cut one open and map a color key. They made it very easy and straight forward to add lights and run a harness; just power, ground, and mount the switch.

This is the wiring diagram out of the '03 FSM, If I'm reading it right the fog lamp circuit only has a 15amp fuse.

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The factory bulbs for the Factory lamps are a 9006 55W

I'm not versed on circuit safety/loads but if the Hella LED pods are 40W combined for a pair(2), looking at 80w total compared to the factory halogens at 110w combined isn't it a safe bet to hard wire the LED lamps to the factory harness (Power and ground) to use the existing circuit?

Less is more and I'd like to to my engine bay and batteries clean and clear, I tested the lights and I think I'll be fine running the spots and floods together, I did get some amber light covers just incase.

 

[Ozymandias]

I would without hesitating, even the factory wiring and relay has a safety in it.
Go the KISS way and use the factory wiring.

 

[User113]

If you are sure that the total current drawn by the new lights is less than the total current of the OEM lights, then you can just run the lights directly off of the OEM fog light wiring, L39 in the above diagram. You just need to be really sure that is the case because they would all be powered through the fog lamp relay in the IPM. If you run them that way (all 4 of them) then they would all come on and all go off together, which also simplifies things. As a bonus of running them directly off the fog lamp relay (L39), if you accidentally leave them on and walk away, the truck will automatically turn them off for you after 5 minutes.

No need to mess with the switch or relay that comes with the lamps. The kit is for a general purpose application, your truck already has everything you need. Although, two separate 30A fuses does make me wonder...

 

[Darkbloodmon]

I'll give it a shot and try using the factory harness then. I'll report back when its done. Thank you for your help.

 

[Ozymandias]

Worst that can happen is that the fuse blows, it is there for this reason to safe the circuit in case of overload. If it blows, wire in your relay for the spots connected to the high beam circuit as a trigger and use the floods with the existing fog circuit. No additional switches needed and wiring stays to a minimal.

 

[Darkbloodmon]

No issues, no fires. Used the OEM lamp harness. It took longer to route the OE harness given it's length. I still have amber light covers in case I get pulled for them being too bright, but they're aimed pretty well.

 

[AnonEd]

Hard to tell from the images (how tall is that tree?) but those look as much a driving light pattern as fog. My fogs (PIAA, Bosch, Hella) all have a clear cutoff along the top that is no higher than the lamp, substantially more beam width than shown, and can be used with oncoming traffic no issues. Again, all speculation since I don't know the geography in front of the truck here,

 

[Darkbloodmon]

Hard to tell from the images (how tall is that tree?) but those look as much a driving light pattern as fog. My fogs (PIAA, Bosch, Hella) all have a clear cutoff along the top that is no higher than the lamp, substantially more beam width than shown, and can be used with oncoming traffic no issues. Again, all speculation since I don't know the geography in front of the truck here,

Fogs on the outer, spots on the inner. They do sit fairly recessed in the bumper so the fog beam isn't as wide. For the light output and better visibility im getting I can live with it.

Here is a google maps pic of the measurement. I centered as much as I could on the white line and backed up to the median till my tires touched. About 155ft or 47M.

 

[AnonEd]

Oops…didn’t know it included spots. Makes sense now!