I don't mean to flood the board with questions but I couldn't find anything with a search and the manual is proving to be hard to decipher.

If I understand correctly, the instrument cluster determines which lights should be on based on the resistance of the signal sent to it from the light switch....I could be way off base here so if someone knows please explain how the light switch works.

I have 5x12VDC LEDs (1W/83mA) that I want to be on when the parking lights are on, and I may want to expand this later to add another set of lights bringing the total to 203mA, but the second set will also be able to be independently controlled.

It may be a small load but I'm assuming I can't tap into the wires on the light switch for the power. so what would be the easiest option to get power when the parking lights are on

 

on my 07 and on others 3rd gens, i have tapped the the switch and/or fog light harness to run after market gauge lighting... no issues

 

There is usually an "illumination" wire on the radio harness that you can tap into for this very purpose. It is only a 10-15A circuit so don't over-draw it.

This wire is usually solid orange or orange with a white stripe... don't remember which it is on our trucks...

 

I never even considered using an illumination wire, and 200mA shouldn't pose a problem.

I have the wires run over to the light switch already though, so does that illumination wire happen to run back to the IC or light switch?

 

Every car is different... all depends on how the interior dimmer switch is wired in...

Just measure the current present when the parking lights are on and see how much room you have for extra current... 200mA shouldn't be too bad... but I wouldn't go over 500mA on it.

Upside is you will also now be able to dim those lights with the OEM dimmer switch...

 

chances are the led's are not dimable, and i do believe the the radio illumination wire on the 3rd gens also is not on the dimable circuit, its just a signal wire, but should still work for your purpos, if you dont have the factory fog lights and switch, you have a free point to tie into, the plug is in there by the head light switch and has power, ground, and lights on/off, if you have factory fogs, you can tap the wires, i have 4 gauges in my 07 tied into the fog lamp plug, witch i was able to access by poping off the dash panel between the driver door, works great! you can also pull dimable power from taping the orange w/black stripe wire from the head light switch to dim convential bulbs, i have also done this with 3 conventional bulbs tied to that circuit for gauge lighting with out issues

 

I have to disagree with the "signal wire only" bit there.

I've done a few radio installs on Dodge's ranging from 98-2008 and most of the aftermarket radios use the illumination for the brightness on the radio buttons. The dimmer switch on most of our 3rd gens (except for TPIM equipped) will work as a potentiometer for the dash lights. Also nearly all Modern LEDs are able to be dimmed slightly (less than incandescent/Filament bulbs), it all depends on their operating amperage and resistance characteristics.

Some will work all the way down to a draw of 25-50mA which gives you a tiny glint of light, and will dim after each LED if wired in series (or not at all if in parallel).

So for his 2002 (non-TPIM) The illumination wire should work perfectly for him, again I'm not there to check first-hand, so I am only working from some personal past experience with mobile electronics installation. Easiest way to test my theory is to check the positive illumination wire (usually Solid Orange) for current/voltage fluctuation when you change the dimmer switch up or down. If his system has both Orange and Orange w/ Colored Stripe then he has positive and negative leads which will 100% give him a nice dimming effect when he adjusts the dimmer switch.

Be careful and make sure that you have 4 sets of like colors OTHER than your Oranges, as I've seen it where some auto manufacturers run out of certain color wires and use orange for speakers.

Measure Twice Cut Once!

 

I haven't checked into this yet, I'm hoping to do so next week when I'm off, but LEDs do dim, the floor lights I installed dim with the interior lighting just fine although I did tie those into the dome light circuit.

measure thrice, cut twice

 

That's odd, I wouldn't expect the Dome Light to Dim.

 

it dims when the lights fade out after closing the door. Otherwise it doesn't.