I will start out by saying the vent covers that are offered by venders seem very nice and I would had loved to own one. However I had some left over materials from other projects and I wanted to save my money for other mods, so I built my own....here's what I came up with.
Sheet Metal, at least 15" x 11 1/2" (~$10)
(8) 1" round self-adhesive backing Gripper Pads (~ $2.50)
(6) 1"x4" self-adhesive strips or about 24" long worth (~ $3)
(2) Aqua_Seal Washers for American Standard Faucets- to put in rubber tire spacers (~3)
Paint of preference (~$5)
TOTAL ~$25 +/- depending on what parts/equipment you might already have.
**I already had the sheet metal and paint from another project so I have about $10 into this**
Angle Grinder with cut-off wheel
1/2" Socket to remove 8 bolts holding on Tire Carrier
T20 star bit to remove 3rd brake light parts
3/8" metal drill bit (a step drill bit works well also)
Foam-Type Beer can Coozie for finding round angle
EDIT: I have since made some spacers to put between the plate and the tailgate and put back in the factory vent cover to allow air to blow out....
1. Using the T20 star bit, remove the 4 screws holding the 3rd brake light together and disconnect the wires. Then remove the 8 bolts holding the tire carrier on with a 1/2" socket. Remove the vent cover by moving it up and down while pulling out. There are "1-way" clips that keep it in place so they will need a little force to get them going the "wrong way". I ended up breaking a few, I hope you dont have the same problem.
Once it's removed it will look like this:
2. Then measure out the cut lines on the sheet metal for the cover. I used a foam-type beer can coozie to trace the curve...it's about 3" round which matches close enough to the curve on the tailgate. Use a square and the following measurements (18 7/8" diagonally both ways will make sure you are square):
3. Then take to it with an angle grinder. Remember to cut more on the outside of the line since you can always take down the high spots later. Check your sides are even with a straight edge:
4. Then use the tire carrier as a guide for where the holes need to be drilled:
5. Drill out the holes:
**At this point I also cut out a section for my CB wires to come through and connect to my TeraFlex CB mount, this may not be needed for your application**
6. Then place the self-adhesive 1" round gripper pads over the backs of the holes. After they are in place I used my step-drill to drill out enough for the bolts to easily fit through:
7. Then place the 1" strips around where the vent cut out is to keep water out. Leave the bottom line open for air to come in and out as it was designed to do (EDIT: You dont leave the vent on, that is just there to make it easier in placing the gripper strips):
8. Then test fit:
9. Paint (insert personal preference in finish):
10. Mount using the original 8 bolts. It's best to torque the top bolts more than the bottom ones, this keeps the opening for air to enter and exit at the bottom. I have read from other vender-sold cover plates that this amount of space left for air to travel should be sufficient:
***FOR ADDITIONAL PICS SEE POST BELOW***