Mod #95: Water Heater On Lights

Mod #95: Water Heater On Lights

Submitted on: 02/20/10

     Category: electrical, lighting
Mod Rating: 12345

(43 ratings)

Loading ... Loading ...
Viewed: 98390 times
Share your experiences and connect with others who’ve actually done what’s described in this mod. If that’s YOU, click the “I Did This Mod!” button. See the FAQ for more information on this very cool feature!
Congratulations! You've “Done the Mod”. You should see your gravatar displayed in all it's glory over in the sidebar. Don't have a gravatar? Visit and sign up for one. It's free and once you do, your new gravatar will appear in the sidebar and in the comments you make on any mod. See the FAQ for more information.

Mod Description:

This modification was designed and completed by ModMyRV member RVfor5. This article carries a copyright. Permission must be obtained from the author before duplication or reposting.

My RV has an Atwood Gas/Electric water heater in it. The switch has a light on it, but it only comes on when there is a problem in the system you have turned on. Because I have small children, and the switch is in the counter at their eye-level, I was concerned that they would turn the switch on or off without us knowing, either wasting resources when we don’t need the heater on, or making for cold showers when I’m expecting a warm one.

Mod Difficulty:

I figured that the solution was simply to put an ultra-low draw LED into the switch that lit when it was on. I wanted the light in the switch because it can be seen from everywhere in the cabin, keeping me from having to inch around to the wall that my manufacturer used for the control panels. I found the LEDs at Radio Shack (link below). There were a few that I could use, but these seemed to fit exactly what I wanted to do. They were small enough to be drilled into the plastic area around the switch. I decided instead of just putting one in (which anyone could do on any single-type water heater), that I’d put one each for each type of energy source.

Recommended Tools:

  • Digital Multi Meter
  • Screw/nut driver (depending on what your manufacturer uses to mount the switch)
  • Wire cutter/crimper
  • Misc 12v Wire connections (depending on preference)
  • ~1 ft. 18 ga. Automotive Wire (if you choose to lengthen the LED leads)
  • Drill with bit sized according to LED package
  • Needlenose pliers (make one step easier)
  • LED light(s)

First step was to gather all the materials. The two LEDS, connectors of whatever format you want to connect them (splits; blade connectors into tap-outs; straight tap-outs, or tying them together in another form depending on your preference – I used one butt-connector). One thing to be sure to have is a good crimper and good knowledge of 12v electric safety since an open connection could cause a fire. If you aren’t certain about what you’re doing in this mod, have someone who knows what they are doing do it.

Second, remove the switch plate from the cabinet, exposing the back of the plate and the wiring. Every RV manufacturer probably wires them differently with different color wires and different styles to bring power to the unit, so again, if you aren’t sure, get someone who is. I’m comfortable enough with 12v that I continued. Using a meter, I verified which connections were positive, and which were ground. Then I was able to discern the two different switched loads. My plan was to wire the positive side of the LED to the LOAD side of each switch, then tie the negative sides together with the other negative wires already tied together by the factory behind the plate.

IMPORTANT: Turn off battery power cutoff/disconnect the coach battery for the 12v switch, or, if necessary, unplug the RV or remove the fuse for the 120v side. Atwood switches are operated off a relay and turn off with the 12v cutoff/disconnect. Verify that there are no hot wires by checking all the connections with the meter.

The LED package tells you what the outer diameter of the post needs to be drilled to. There are several locations that you could choose to put in the LEDs, but I wanted to put them in the plastic between the light and the switch to keep it neat. I chose to leave everything intact while I drilled so that I could place the LED exactly where I wanted them. The front of the LED has a little lip so that it doesn’t slip through the mounting hole, meaning you have to plan on drilling the hole a little away from any non-flat part of the switch so that the LED will sit flat. I drilled my holes as even as I could and then used the nuts provided to tighten down the posts (needlenose pliers help with this, but fingers work).

I decided to remove the manufacturer connectors (Orange and White wires) and twist in the LED red wires to the respective load wires, then crimp new connectors on those, making sure that neither wire was loose by pulling lightly on it. You can see the connectors in the pictures. Tying in the black wires was a little more difficult because of two things. One, there is not a lot of space there; two, the leads coming from the LEDs are fairly short. From the photo you can see how the ground wires are tied in – I cut the factory connector off the wire going to the switch, then tied the two led wires together, butt connecting them to the factory wire. Though there are a number of ways to do this, I chose the method I did because I thought it offered a better connection. Tying the two 18ga. LED wires together allowed me to just use the standard size butt connector with the factory 14ga. wire. Before putting the switch back in place I turned the 12v back on and tested the water heater with each switch, running the heater long enough on both switches to be sure there wasn’t a failure to the middle red light. I replaced the switch making sure that the wiring was tied up above the drawer below so that nothing got caught.

The two LED lights work great and aren’t so bright as to be distracting at night. I know when the kids turn on the water heater, and it turns out to be a reminder not to waste resources when I don’t need to use them. All in all a win-win for only about an hour of invested time, and about $6 in materials.

ModMyRV recommends these parts for this mod:

Crimp Tool and Connectors Package
Green LED with Holder - Flat
Green LED with Holder - Rounded

Share the mod love:
  • Facebook
  • TwitThis
  • Digg
  • StumbleUpon
  • MySpace
  • Google
  • LinkedIn
  • Pownce
  • Reddit
  • Technorati
  • Yahoo! Buzz
  • E-mail this story to a friend!
Print This Mod Print This Mod

14 Comments For This Mod

Sort by:

  1. ron46

    Just curious - why not just replace the rocker switches with green lighted ones?

  2. RVfor5

    Good point, and an easier way to do the mod. Personally I had a very specific look in mind and hadn’t thought about going that route. (I’m well known for over-engineering…) ;)

    Replacing just the switches would have meant only needing to splice into the ground wire and making connections there. Good thinking.

  3. ModMyRV

    I know the feeling RVfor5! I sometimes get blinded by narrowly focusing on exactly what I want to mod and forget that there is ALWAYS another way to accomplish something. That’s why this site was made so folks like you and ron46 can share the “other” ideas. ;)

  4. ywgclarke

    I did this mod with a slightly different LED from Radio Shack. Larger red ones that I put directly above the switches. I went with them because they have the built in resistor and they guy said they are more tolerant of voltage variations and would last longer. I had to be careful to center the hole, as they just fit. Far cheaper than replacing with an illuminated 12V switch and sourcing the switch. It took less than 1 hr and cost less that $5.00. Great mod! I don’t understand why these controls don’t have an indicator light in the first place.

  5. ron46

    The switched are only $3.99 each from O’Reilly’s Auto Parts. And no drilling, just add a ground. Far easier than adding LED’s.

  6. GrandFunkRR

    I have an Atwood DSI 6 Gal water heater. It’s on a 2003 33′ Nomad 328 Scout. I currently have two separate locations for my gas/electrical switches. The electrical switch looks like a residential light switch and by the door. We have kids and the electrical switch is constantly, (and I mean constantly) being switched on inadvertantly. Would I be able to convert that in a switch and combine with my Gas switch into a combo plate that looks like this Mod?

  7. flyguy_helo

    I already did your mod and love it. I was wondering, would it be difficult to install a remote switch to be able to start the water from my bedroom. I turn the gas off for the night but I hate to get up to put it back on for the morning shower. How many wires would I need to extend the kitchen switch to my bedroom to start it remotely.
    I am open to any suggestions.

  8. Frank

    I just did this mod (and #100) today. I bought a blue illuminating rocker switch from Adv Auto Parts (84835) $5.89. I was able to pull the old switch out of the frame and replace it with the blue one. Hooked up the spade connectors to the new switch and new wire from the ground pin on the new switch to the ground pin on the adjacient H.W. lock-out ground terminal.

  9. Kevin

    The original mod was perfect! I actually tried to find illuminated rocker switches, but none of them fit properly. So, I went the original mod and couldn’t be happier. Besides the water heater control switches, I also did the two main switches for the inside and outside 12V lights. Now I know at a glance whether any of the 12V circuits are on and drawing power. Thank you!

  10. Retired Alex

    Completed this mod yesterday. There are no Radio Shacks in Canada anymore, now called The Source. They carry a very limited amount of electronics parts. LED lights are not on their inventory, so I went with small 1/4 inch incandescent lights. Worked out well.

  11. mikeintn

    Did this mod with the green LED specified in the pictures ( Radio Crap had an orange and red but they were bigger) Mine is a 98 model and I put the LED across the Yellow (which is Brown leaving the water heater) and Blue. Comes on when WH is in on and off when turned off. Just what I wished I had when I kept the water hot in the driveway for 2 months a couple years ago.

  12. Jim C

    Did the mod, it was a breeze to do, and I have definitely enjoyed the benefit of having lit indicators as to what I have on whether gas, electric or both! Lighted rockers seem like a good alternative but I am happy I put the LEDs in as per the mod. Great job!

  13. perrylw

    I did this mod using RV Designer S247 Rocker Switch from Amazon. These are black switches with a red LED. They also make a S249 switch which is black with amber LED and S241 which is a white with red LED. As mentioned earlier, all you need to add is the ground wire, which can be spliced from the reset light ground wire.
    The + pin on the switch is for the 12 volt supply. The – pin on the switch is for the ground. The unlabeled pin goes to the water heater.
    These switches were exact replacements into my Suburban gas and electric water heater switch panel.

  14. Lou

    This is a great mod. I like the idea of the lighted switches. I’m putting this on my list.

Let's hear your comments about this mod!

If you are not a member, please consider registering so you don't have to fill out this form each time you comment.

Subscribe to the ModMyRV Comment Feed