I got tired of how my block heater cord and my battery tender cord were just run out the grill putting excess wear and tear on the cables and actually made my block heater cord break. I got this idea from how ambulances and fire trucks are set up for while they are in the garage, just mine isn't nearly as a professional install.

Step 1: go to Lowes (or other home improvement store or hardware store) and purchase the following: A out door wet weather rated outlet cover, a heavy duty 3 way splitter, and a plastic gang box (you could use metal too, but I used plastic to make modifying it easier). You will also need a couple heavy duty zip ties, electric tape, dielectric grease, maybe some silicone, spray paint, masking tape, cut off wheel/grinder, hack saw blade or reciprocating saw, a file, a marker and some drill bits.



the three way splitter I got was $4.78 (the most expensive piece). You want to make sure that all three plugs face out one way just like the one pictured. You don't want to use one that splits in different directions like this <^>


The gang box ($2.76) I got was plastic so I could modify it easier. The tabs on it I ended up having to cut off to fit properly.


The outlet cover ($3.51) I got was metal, and its rated for outdoor/wet locations. It comes with some plastic pieces but I didn't use any of them, but you will want to use the gasket type material that comes with them to seal the cover to the body.


My second step was to remove the back portion of the gang box, I measured how far in I wanted the splitter to be and cut off the back accordingly so that the face (female side) of the splitter was flush with the new opening in the back of the gang box. I used a reciprocating saw to do this, but a hack saw or cut off wheel would work too.


Step 3 was to remove some of the side material of the gang box to allow the wide splitter to fit in snug. Remember you do want this fairly snug so it wont move around. This gang box already had punch out holes almost exactly where I needed it anyway so it worked out pretty well.



Step 4: Mark where the slits are supposed to go for the zip ties. I positioned mine so the zip tie would be right across the back of the splitter. I also marked both side of the gang box.



Step 5: Using a small drill bit cut the slits into the gang box in all 4 locations. A razor knife or some other tool could used for this as well.


Step 6. Position the zip ties through the gang box and pull tightly to make a snug tight fit. then remove the excess zip tie.



Step 7. Find where on the body you would like to mount the outlet cover. I choose the front under the passenger side head light just for ease of access and that's where my cords were already run. I didn't want to put it on the side of the fender like an ambulance or firetruck because I thought that would look a little weird. I centered mine with the little nipples ont he light housing itself and made it so the top of the crease line in the body would be the top of the outlet cover.



Step 8: I then traced the inside opening of the cover onto the body, then I traced the outline of one of those plastic pieces that came with the cover to have a larger opening, this way there wasn't any sharp edges right at the opening for the extension cord to cut itself on.



Step 9: Mark, center punch and drill the holes for the mounting screws. (remember these are the ones that will line up with the gang box.)


Step 10: POINT OF NO RETURN! Cut into the body using a cut off wheel and cut out the outer most tracing. A hack saw blade or a metal blade on a reciprocating saw can be used for cutting the corners of the hole easier. Once the initial hole is made, go back through and clean up any rough edges or burrs with a file or grinder.
rough hole


cleaned up hole


Step 11: Spray painting bare metal. Tape off for over spray and use (any color) spray paint for touch up the areas of bare metal. I taped off only what wouldn't be seen behind the outlet cover gasket. I applied a couple coats of paint to keep rust from forming. You may want to tape off more than what I did. I still got a little over spray, but my paint isn't anywhere near perfect anyway. I also painted over the freshly drilled holes too to keep them from rusting hopefully.



Once the paint is dry remove the tape.



Step 12: position the assembled gang box behind the body panel in which you decide. I had to notch it to slide into that piece of metal. if I would have positioned the whole thing over another 1/2-3/4 of an inch I would've been clear. Which actually notching it helped to hold it in place while I tried screwing in the cover. (A second set of hands would also be helpful here) I did have to cut off those tabs on the gang box in order for it to fit properly.


I found it easier to push the screws through the gasket material with out the outlet cover and through the holes in the body and into the gang box to get it started into the gang box. The outlet cover has bigger holes next to the ones you will need so that the head of the screws will fit through them holes. Be sure not to tighten all the way down yet so you can get the cover on.


Then you can put the outlet cover on and tighten the rest of the way down, but be sure not to tighten too much, you don't want the plastic gang box to strip out or crack.


Step 13: Plug in block heater cord and battery tender cord. I have a third spot still open, I may put a oil pan heater on too some day or I was also thinking of just plugging in a short extension cord there so that if I ever needed one while working on the truck I would have it and just have to have the truck itself plugged in to have power.


Step 14: Step back and admire your work



By no means am I a metal worker or even a good fabricator, I'm just a back yard engineer with a few ideas and a few tools. I made this with under $15 worth of materials. I may go back and cover the connections a little better but I think they are alright for now. The only thing I don't like is how the outlet cover is putting a lot of pressure on the extension cord while its plugged in. I may make like a little kick stand/prop thing to hold it open while its plugged in.

Personally, I think I did pretty well for how little metal work I do. I'm sure it can be done better, but I only have a couple hours of time invested in this project. Hopefully this helps anyone who thought about doing this to their own truck.

 

Just for the record the plug ins on emergency vehicles unplug themselves as soon as you turn the key on. Prevents ripping off cord ends when they forget to unplug them while also saving time

(Cant remember where I found them but some website had the plug ins for sale but wanted something like $200 each)

 

Slick, I'd like to do similar eventually.

 

Nice work there!

 

The company that makes the outlets you are referring to is Kussmaul. They are pretty pricey.

 

Yeah, my friend was telling me about those, but I didn't need anything like that. If I found a used one cheap somewhere I would pick it up but it's not that important to me.

 

Very nice work...

 

freightliner trucks use a similar plug for the block heater, that's what I plan to use, chrome plated, don't have a price right now..

 

That's a great idea, nice job.