Around-Oz: Living the Dream!

DIY - Installing a Pilot Light on the Dash and on Top of Your Dometic 3 Way Fridge

Without doubt you have to make a few changes to your life as you get "older" and start forgetting things - like is the Dometic 3 Way Fridge actually running on 12 volt? Many of us have installed the excellent "fridge switch" from our good friends at RV Electronics and others with a bit more know-how have linked the 12 volt supply to the ignition or oil pressure switch using a relay. Now you do have to be careful doing this with super high tech vehicles as many wires do more than one job using multiplexing. Using the system outlined here, you can use a more simple approach. It also works well if you already have a fridge switch or a relay. Interestingly Dometic now recommend a relay yet you don't even need one hand to count the manufacturers heeding this advice! You can take this project up a couple of notches by doing similar things with your Winegard aerial and your steps (indicates if you have forgotten to lower/retract.

Pictured above is a "blue" pilot light mounted very neatly in the dash of a Mercedes Sprinter. The light mounted above the fridge in a Winnebago Leisure Seeker lets you easily realise that the fridge is on if you are stopped for instance. The ultimate set up would be to have another green light to let you know that the fridge is actually running on 240 volt. It amazes us that Dometic don't supply this as standard as the cost is really peanuts considering a large fridge comes in well over $2000.00.

Shown above left is a range of pilot lights. These came from Jaycar and cost from $2.40 to $$5.00. The Narva ones can only be bought from auto electricians and the blue LED one costs $2.70 and the other one using a globe is $7.40. So first up we will do the one above the fridge. Most fridges are installed with a gap above the fridge. We drilled a hole in this, then carefully checked that it was in fact clear by poking a dowel in there. You only need to push the lamp into the hole, so keep the size neat by going up a little at a time, or use a rat tail file. Now getting a wire down to the back of the fridge where all the electrics live can take an horrific two hours! You learn a few tricks when you have to "wire jerk" in motorhomes! One trick we use is to poke a string with a bolt on the end through the hole using a bent coat hanger as shown above right. Best to disconnect ALL 240 volt including any inverter before you start poking around. Now if you are due to win Gold Lotto the bolt will just fall down behind the fridge fins. But in real life it always get stuck. In our case there was a power point on the outside. We removed the screws and put a 2" hole though the wall. This let us poke a mirror on a stick behind the fridge. You can also fish around from the outside fridge vents. WE use that yellow joining strip that you can find on most building sites - wonderful stuff!

Now we move onto the dash. Now car dashboards can be a bit of a mystery, but most work on the same principles. Try to resist the urge just to plonk your light close to the floor where access is easy. You MUST be able to see it out of the corner of your eye for it to be effective. Most Aussie trucks come with "blank" switches. Iveco, Mercedes, Transit and to a lesser degree Fiat all fall into this category. Getting them out can be tricky. Usually they don't light being prised out from the front. They do however readily pop out if squeezed from the rear. Best to pick one near an ash tray or other opening. The picture below left shows how to remove change storage hidey hole. Simply lift up. Drill a hole in the blank plug making sure to get it central. We used twin 4mm autocable. The blue LED is very sensitive to hole size so follow the recommendations on the back of the packet if you like the look of this light. It uses spade connections so don't select it unless you have a crimping tool.

We ran our wiring under the floor covering. We then exited the cab and ran it under the floor using that split corrugated conduit and this was clamped using nylon saddles. Now the two cables are joined at a new terminal strip. Get one with large holes from your auto electrical shop, Dick Smiths, Jaycar or Whitworths Marine. They come as a strip. You can if you are clever enough connect into the black box shown in the picture on the left. We took the easy way out (away from the 240 too!!) and simply broke into the plus and minus going to the elements on the right. BE EXTREMELY CAREFUL NOT TO CUT INTO THE 240 CABLE. It is clearly labeled and has a white sheath. We also covered our finished cables with conduit.

This is an ideal project for those new to DIY but paid attention during lessons on electricity at school. Yes it can take a lot of hours for what seems a simple task, however if you want to run wiring safely and neatly it just takes time. We have been using the system for a few weeks now and have to report that it really works fine. Total cost should come in under $30.00 provided you don't lash out and buy rolls of conduit and cable.

Bob & Chrissy Eustace

WARNING:- If you use the Narva LED light, remember it is polarity sensitive - it doesn't blow up though if you get it wrong. If it doesn't light up when it should then simply swap the wires.


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Last updated: January 17, 2008
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