DIY: Heritage Grille + Diode Dynamics 18" light bar on a vehicle without factory AUX

[Baltimore]

Swapped out the OEM bright chrome grille with the bronze heritage grille. opted for the @Diode Dynamics 18" light bar because I wanted to remain street legal (and this was purchased 3 months ago, so way before they announced their 20" option at SEMA last week). I opted for the kit approach from Rave Offroad (debate on that approach can be left for the thread it's all in, trying to keep this clean at installation approaches and looks). Kit came with: grille, light bar, mounting brackets, Diode Dynamic single heavy duty wire harness, 3d printed camera bracket, and interior "TRD" dash switch.

I did not document all the steps, but watch both the Rave Offroad grille swap video AND the Diode Dynamics Fog Light swap video. There are things that one does that the other does not, or fails to touch on. Watching the combination gives the most insight to be prepared. Non-wiring related tools you'll need are: a trim pop tool, a 10mm socket, a 12mm socket, a flat bladed screwdriver (stubby, for in the wheel wells), some socket extensions, and some faith that nothing is breaking when you hear the pops/snaps. See the combined videos for removal instructions and recommendations.

If ordering the dash switch from Rave, make sure you receive the correct switch. If the switch says "TRD Light Bar", it'll most likely light up blue to match a Tundra interior lighting. If the switch says "TRD Grille Light", it'll most likely might up white to match the Tacoma interior lighting. If you receive the incorrect one, just call them, they were awesome at getting the correct replacement out to me.

I originally got the wiring crossed (a quick call to Rave Offroad sorted it out and they said it was the most common problem they got calls on), so if you finish and your "on" light within the switch is staying constantly lit, you crossed your power source and your relay wire - flip them to correct.

Wiring connections for the dash switch (done in order of the switch wire harness):

Purpose	Switch Wire Color	Source Wire Color
Illumination negative (ILL-)	Black	White (factory)
Relay	Green	Blue (Diode Dynamic harness)
Ground	White	Black (Diode Dynamic harness)
Power	Red	White (Diode Dynamic harness)
Illumination positive (ILL+)	Yellow	Beige (factory)

Call outs related to photos included:

• Yes, I have the "factory AUX" plugs, but none of the associated wiring/relays/fuses. Believe me this was checked first.
• Illumination tapping: used an approach that was successful for me in the past when vehicles let you swap out head units (remember those days?). Solid 20g (or 22g) wire push inserted into the back side of an existing plug until it seats deeply serves as a "tap" without any actual alteration to OEM wires. a bit of electrical tape after keeps them from being able to work loose (stripped ends around about 1/2" or 1cm long).
• I snipped the end off the secondary nipple through the firewall gasket using side cutters (it takes some work to get them to it). There's a line molded on where to cut to get past where it's solid. The interior opening is the exact size needed for the DD wire harness (once you slyly remove the plastic plug temporarily).
• If you use a very small flat bladed screwdriver, you can press the hold-tab within the white plug fitting to release each of the brass blades and be able to back them out, thus allowing you to electrical tape them into a small point for getting through the gasket hole without over-sizing it.
• I took a very specific approach for my wiring because I knew this was the only "AUX" I intended to add and I wanted it water tight without adding a lot of extras that I never plan to use. You may opt for simpler or more complex depending on your end goals.
• I used yellow electrical tape where I wanted to wrap things. A habit of mine to not use black. Makes it easy to always know what I put in, versus what was OEM.
• I took a ton of measurements for the grille bar opening, minimum edge on back, maximum edge on back and spent weeks brainstorming approaches for taking care of the approx. 1" or 2cm gap on either side of the light bar and the grille cutout. I ended up on a solution of using thin, highly bendable, anodized black aluminum. I was able to get a 5pc set of "cards" off amazon for a couple dollars. Then it was painter's tape, a bench vice with non-marring pads, and a high speed drill bit. Bent the card one direction approx. 1" or 2cm from the short edge, then approx 3/4" or 1.5cm further bent in the opposite direction. Then dry fit to mark where to drill for the bolt pass-through. Bends where then manually manipulated to form the target shape, with the goal of mild spring-like tension to hold it flush to the grill face. Once everything was set in position, needle nose pliers were used to twist and tweak alignment and pressure.

Steps I took:

1. Fabricate grille gap closures
2. Install light bar to grille so that light harness went to driver's side
3. Install grille to truck, route plug up and strap to secure on grill mount point near washer fluid fill
4. Fully disconnected battery (negative and positive) and let everything drain for a few minutes before the next step
5. Opened the driver side engine fuse&relay box and removed the sub-harness coming in on the front center corner (disconnect the five plugs, then double tab to release the harness and fold it out of the way)
6. Removed the four mounting bolts from the F&R box, and cut each of the two zip ties on the wire harness ports on the front and rear of the box
7. Used zip ties as "extra hands" for getting all NINE (9) snap tabs released around the F&R box. There are two on the side wall, two on the front, one on the engine side, two on the cab side, plus two very fragile reverse tabs on the cab side harness port. I worked them one by one pressing them in and sliding a zip tie in place to keep the tab from re-setting until I had everything released-ready
8. Gently lift up and lean towards engine. NOTE: you won't be able to move this as much as you might want. It's TIGHT, but really just needed about 2" of clearance on the sidewall side of the box to work wires through the harness ports
9. Strip the wire guard wrap off the DD harness leg that contains the power and ground wire taps
10. Remove the metal mounting bracket from the DD relay, it'll just get in the way
11. Feed grille side of wire harness down through vacant bay in the F&R box and work it out of the front facing harness port
12. Feed the grounding wire tap down the same slot and out of rearward/cab side harness port. Keep it as clean and direct as possible to give yourself maximum length, you'll need it
13. Now feed the plug side of the wire hardness down through the same slot and route through rearward/cab side harness port
14. Pull slack of each cable all the way through so that you have just enough slack left to pull the relay connection up a few inches above the F&R deck (yes, your power source / hot line will be loose and not run anywhere yet
15. Tuck all wires inside the F&R box into place and make sure your new runs are in the channels and not about to get pinched
16. Re-clasp the upper and lower box shells together, make sure to confirm all nine points are latched again
17. Put new zip ties on each harness port to secure properly
18. Bolt the F&R box back down, re-attach the sub-harness, plug sub-hardness plugs all back in (at this point, you're back to "factory")
19. Route the ground wire tap under the brake master and you'll find a factory grounding point on the sidewall just past it on the cab side. The DD hardness wire is the perfect length for reaching this location, but will not make it to the factory point closure to the firewall grommet. I used a mid-length extension to be able to reach the bolt and loosen it enough to slide the out-of-the-box (OOTB) blade into the stack and tighten back down. GROUND... CHECK!
20. Take the red wire tap and cut the OOTB blade off the end. Slide some heat shrink onto the wire, then crimp on a 14g-16g insulated female spade connection. slide heat shrink into place and set. This will be the exact size for a very snug fit (it ain't moving without some plier force) onto one of the unused relay blades within the F&R box. I opted for the one that I felt was the cleanest. POWER... CHECK! (Do note, this setup means your relay has power all the time, even when the truck is off you can turn on your light bar by pressing the dash switch)
21. For the wire going to the grille light connector, route along the outer wall and over towards the washer fluid fill and secure with enough slack to connect/disconnect
22. Coil the slack tightly (about a 6" / 12cm diameter) and you can easily zip tie it against the sidewall between the F&R box and the ECU mounted in front of it. Alternative would be cut the wire to remove the slack, re-crimp, and heat shrink. I didn't want the break/penetration point.
23. slide a zip tie through the back of the relay and work the slack wire into the bottom of the F&R box, use the ziptie to secure the relay from lifting up and moving around. I zipped it to the rail between two vacant bays. Then tuck inline fuse into another void to keep it out of the way
24. Clip off the end of the lower gasket nipple to expose the pass-through
25. Open up the interior dash sufficiently to access the firewall gasket and switches from the inside (see: https://www.tacoma4g.com/forum/thre...drivers-switch-panel-trim-removal-steps.7138/)
26. I wanted to take advantage of the OOTB shrink keeping the wire sleeve together, so I used a small flat blade to release each of the three brass blades within the white connector fitting, I then wrapped them in electrical tape to form a point/needle. I recommend wrapping the tape until your past the heat shrink, otherwise the rubber on rubber will fight you. Apply a small amount of liquid soap to lube things up and the wire bundle will slide right through the gasket with a precision fit to the inside of the cab. I opened to pull all the slack through and then cut it off at a reasonable amount of play within the cab
27. Tap into the illumination circuit. I did so by stripping 2-wire 20g solid bell wire about 1/2" or 1cm and sliding it into the back of another factory switch, then wrapping with tape so that it couldn't work loose. I then brought that 2-wire together with the 3-wire DD harness to have my five (5) wires for connecting.
28. Connect wires as specified in the table above, wire nut (or crimp), and secure. Make sure you tie down with tape or zips the full path of the wires so that you don't get "random rattle" later on
29. At this point, you could reconnect your battery to let things power up and to make it easy to test in a short bit. Or, wait until the very end.
30. There are two taps to release the switch blank, they are on each side of the plug on the back (where it is tight to the next plug). use a trim tool or screwdriver to release one, then the other. The blank will push out to the front (dash face)
31. Insert your new grille light plug from the dash front, push until you feel it seat securely
32. Plug in the switch harness, finish securing any loose wires
33. TEST before dash reassembly: pressing has the grille light and switch status light come on. Turn on driving lights and check illumination is working and toggles correctly. Pressing again has the status light and grille light go off. If the status light stays on non-stop, your power and relay are likely swapped and you'll need to flip those wire connections
34. Close up your dash
35. Tape/seal the wires passing into the gasket on the engine side
36. Do one last double check on everything and then close it all up
37. Enjoy!

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