Decided to do the diode mod to my rear lights. What was the case is that only one of the 3 lamps in the crew cab rear interior fixture would turn on on door opening or by dash dimmer switch activation. This disagrees with the way I *think* it should work, and it also disagrees with the way the wiring diagram seems to describe the interior light as having TWO single-pole, double-throw switches. Upon removing my interior light off the headliner, I discovered that the switches for the "reading lamps" were merely single-pole, single-throw - meaning there was no 'door' position, only 'off' and 'on'.



By simply adding two diodes with the anode on the door/dash dimmer switched circuit (controlled by the BCM's FET, to provide the "fade" effect) and the cathode on the respective map lights, the two map lights on the side will illuminate along with the centre position lamp. By using a diode instead of a jumper wire, manual user activation capability is retained and the manual (local switch) activation of one map lamp does not cause the rest of the interior lamps to turn on. Due to the use of a diode, a slight voltage drop can be observed however the performance degradation is insignificant compared to the previous operating mode of no lighting at all. The end result is... bright. The back row really is for my tool storage and since the map lights are forward-facing, they light up the footwell area and the under-seat tray significantly better.

I used 1N5400 diodes with a 3A forward current rating and a 50V reverse bias rating. I selected these because I had ones kicking around but the generous current rating is nice even when driving my LED lights which are pretty low current.

 

That's a great idea! I'm going to follow your lead and do the same to mine.

 

I'm clearly not smart enough for this thread LOL. What does this mean in layman's terms? Looks like a good mod, I just don't understand it lol.

 

It means instead of having one light bulb turn on when you open the door, all 3 come on which provide more illumination.
I considered other methods of doing this mod but this way I keep the ability to turn on the light manually (reaching up and pushing the switch).

 

Good idea Trent, I tried to sent reps but my rep gun is empty. Well not really empty but I guess I need to spread the love.

Somebody rep this guy for me. I love this idea.

 

Trent, Are you using the standard bulbs or did you switch to an LED bulb?

 

I also like the idea, Thanks will be adding this when I get some time and a little warmer weather.

Rich / N1NCZ

 

Great mod Trent, well done

 

Nice Idea and great job, thanks for posting.

 

Yeah I switched to LED interiors a few weeks ago, much brighter in there.

 

Great mod. I'll have to do this one. I already switched my regular bulbs out for LED panels I had sitting around. Used half the parts from a Putco 08 SD interior kit for the rear and a couple of 194's at the front.

 

Sounds good guys, Trent what brand and bulb numbers did you use? I will have to order a set as no one around here carries them.

Thanks Tim

 

When did Trent add the MM? I missed this...

 

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Gotcha covered, Tim

 

Excellent mod Trent, never really noticed the rear lighting until last night & a truck full of Boy Scouts thinking, man I could sure use a little more light in here. From the pics, looks like your truck really lights it up inside, I like it!