DIY Adjustable Dimmer Mod – 12V RV Bedroom Light

A few months ago, an LYRV forum member posted about adding a dimmable light switch in his new Grand Design fifth wheel.  He said it worked great to dim the LED lights that were just too bright.

Reading his post got me thinking. Maybe I could use the same little PWM motor controller box that I used a mod for adjusting the bathroom fan speed as a light dimmer. We have a 12V light fixture directly over our bed’s headboard. Being so close, it’s a little bright. Anne is a late-night reader, and I’m sure she would appreciate the ability to adjust that lights brightness.

Finished Install

In this video, I first bench test the concept using my little Jackery 500 power box as the 12VDC power source. Once I had proof of concept, I went to work installing the PWM power controller box into the RV ceiling area and splicing it into the existing 12VDC supply wires.

Inserting PWM into the wall

I added a 3 amp inline fuse just for extra safety and also tested it functioning at full power for an hour or so before sewing everything up. I wanted to make sure the box didn’t get hot. Being that it’s rated at 9-60 VDC and up to 20 amps, the meager 1.5 amp current the lamp required created virtually no heating. The actual light bulb produced far more.

Light being installed over bed

Disclaimer: Working with electricity can be dangerous. I’m not a certified RV technician, merely an RV owner. This post and video should not be taken as instructional. If you decide to do a similar type mod as depicted in the video, do the research and be aware of all the risks involved. I accept no liability; you have been warned. – Ray

Video Detailing my RV 12V Light Dimmer Mod

I found the PWM controller I chose worked better for the OEM incandescent lamps versus my aftermarket Starlights LED lamps. The LED light only dimmed in a small range at the end of the adjustment control versus the incandescent, which had a more linear smooth dimming action. So I decided to swap that fixture back to the old school incandescent bulb.

This mod has turned out to be a big hit with my wife, Anne. She gave it a try last night and loved it. Great for her late-night reading and nice not to be blinded by the bright light when going to bed or getting up during the night.

See More of my LYRV Mods and Upgrades on the Archives

RV 12V Light Dimmer Mod using a PWM motor controller box

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