help with splicing wire for fog lights

titan711 · 01-22-2005, 04:43 PM

I installed my pia 1400 lights the last thing i need to do is splice the power wire somewhere... has anyone done this before. I couldnt figure out how to get the the headlight wiring i was going to try to splice into there. thanks

bestatchess · 01-22-2005, 05:17 PM

Are you using an aftermarket dash mounted switch & relay for the PIA lights?

If so, I would run the power wire of an appropriate gage (rated for the amount of watts drawn by the lights) to the accessory terminal on the positive battery terminal, with an appropriate in-line fuse holder & fuse of the correct amperage. If you tap the circuit for the headlights, you are probably going to blow a fuse if you turn fogs & headlights on at the same time.

jburson250 · 01-22-2005, 05:35 PM

Without looking at the PIA website, I'd guess your 1400's use 55 watt lamps. You'd be making a mistake to splice into any existing power lead. I installed PIA 1500 backup lights in both trucks last summer. These 55 watt lamps came with a wiring harness, switch, relay and fuse. Power was connected right at the battery. Please search for my PIA 1500 backup light thread if youre interested - it was probably a 10 megabyte post - I described the install in detail.
Apparently, you just have the lights and nothing else. Please listen to what bestatchess is saying. Given the audio install he did, he's the expert when it comes to powering non-OEM stuff in a Titan.

cali-titan · 01-22-2005, 05:47 PM

Splice it to turn on the relay and then the relay will turn on the lights, relay will use very little power... if you splice to turn the lights (no realy) then you will have problems.. my 2 cents... I did it in my Hardbody, turn on the parking lights which will power the realy and then the fogs lights, and never had a problem.... but either way will work I mean with a switch or with a relay.

titan711 · 01-22-2005, 11:51 PM

well i have the stock pia 1400 wire harness. i took it off my old car and forgot how it was installed. i have some insturctions from the pia tech

there are 3 wires 2 are thick and 1 thin, the 2 thick wires go to the battery terminal one for pos and one for neg, the thin wire im suppose to splice into some power source thats where im not sure which wire to use. I guess its to powe the relay or something?? the harness comes with a relay.

i just dont know where to splice the 3rd wire into thanks for any help

falchulk · 01-23-2005, 12:19 AM

You ca take it into the cabin and connect it to a switch (if you dont have one get an automotive switch from radioshack or an auto parts store, the king that lights up while on s best) and mount it in one of the many switch blanks in the titan. You would then run the other side to any 12v source in the cab. If you use one of the blanks under the radio, grab the 12 volts from the left outlet (always on) or the right (switched with the engine to prevent leaving them on and drainig the battery). If you really really want them on all the time when the head lights are on (I would not do this personally) you will need to tap the wires that go to the headlights to trigger the relay, you can use the in line crimp connectors that clamp on to a straight wire and bridge it to another.

titan711 · 01-23-2005, 01:53 AM

i was looking at my stock pia 1400 wiring harness i pretty sure iit comes with a relay its a long plastic piece that the 2 fog lights wires connect to. the relay then connects to the activation switch and branches off into the activation switch and 3 other wires.

1 thick white wire that goes to battery
1 thick black wire that goes to battery
1 thin white wire that activates the relay i think. i will splice this into the parking light if i figure out how..i read on another post that you can access the parking light wire taking off the front grill or sometjhing like that.

Is anyone familair with the wiring harness of piaa 1400 lights? becuase there is not fuse on this wiring harness. the wires that go directly to the battery have never been cut so there was no fuse going there.. only place it might have gone was on the thin white wire to activate the switch.. should i put a fuse there.. or is the fuse built into the relay thanks.

titan711 · 01-23-2005, 02:01 AM

i just found out from piaa tech that the plf5a / 1400 fog lights relay has a built in fuse in case anyone else was wondering. i just need to splice into the parking light now

bestatchess · 01-23-2005, 10:49 AM

Quote:

Originally Posted by titan711

i just found out from piaa tech that the plf5a / 1400 fog lights relay has a built in fuse in case anyone else was wondering. i just need to splice into the parking light now

The rule to follow (for safety purposes) is that any hot lead should be fused as close to the source (e.g. + battery terminal) as possible. So your relay/fuse should be located close to the battery.

The concept is that if you get a short in a hot lead between the battery and the fuse, it will be an uprotected dead short until the wire burns in half, which, depending on the gage of the wire, might be after your truck catches fire.

It is good to keep an eye out for this even when you have the so-called "professional installers" do any work on your truck. When I had an ARE shell put on, the installers ran an unfused wire from the battery, under the truck, back to the shell to power the dome light in the shell. No fuse, no-split loom to protect the wire, and to top it off, they ran the wire through the front suspension in a manner that caused the wire to rub against metal everytime the suspension flexed, which would have rubbed the insulation off the wire in short order. Fortunately I inspected their work when I got home, added a fuse, rerouted the wire and ran in split loom.

It appears that you are going to splice the relay trigger to the parking lights. This is fine, as the relay trigger draws very low current, and operates to close the relay contacts for the power circuit. So everytime you have the parkling lights on, the PIA lights will turn on. If you want independent control of the PIA lights, you can run the relay trigger wire to a switch connected to a wire that goes to +12V only when the ignition is on (to prevent you from leaving the lights on and draining the battery). When the switch is open, the lights are off. When the switch is closed, the PIA lights will come on, but only if the ignition is on. Some people put a switch in one of the blanks on the lower left driver's side dash panel, and switch the relay trigger lead to provide independent operation of the fog or driving lights. For this purpose, you can fish the relay trigger lead through the hood latch release cable grommet.

Also, you might want to check your local laws regarding running the driving lights w/ high beams, etc.

titan711 · 01-23-2005, 01:16 PM

thanks.. looks like im doing it right the pia relay has a built in fuse according to piaa tech. so i just have to splice the trigger wire in now..

thanks