my advice on this topic of mounting aftermarket lights to the fron GM Brush Guard is contained elsewhere off-topic, thought now that I have a pic I should clean it up and repost here. The problem we have to solve for is the fact that there are no aftermarket light tabs, and you cannot simply drill into the cladding because it alone will not support lights very well, and there is no metal structure underneath the cladding to drill into. My fix is to install a cross member, made of a readily available piece of angle iron, using existing bolt holes.
If you obtain the GM bar for the Av, lay it face down using the cardboard box to protect from scratches, or if you have it on the Av already, detach it and lay it face wond on a few towels. You will see that the two chrome elbows on each side are bolted to the black frame of the guard with two bolts at each of the four tube end attachment points. What I did was I got a 48" length of zinc plated angle iron (Home Depot sells it) in the 1 1/4" size, you could and maybe should go with 1 1/2 " for even more rigidity. ?
I used the aforementioned bolt locations for the top of the bottom tube attachment points, ?that corresponded with attaching a piece of the angle iron cut to fit inside of the two black plates, positioned so the angle is at the top and back (when facing the unit from behind, as we are now), where the top side of the length of the angle iron would lay right up against the underside of the cladding. (remove these two bolts for now, and you will need to buy two bolts and nuts and lock washers about 1/2" longer - also from Home Depot, zinc plated for no rust). Measure this length carefully, note also that it is not a perfect 90 degree joint at the sides, as it flares a bit. Well, using this measurement and erring on the side of being slightly too long, mark the angle iron for length, and add 1 1/4" (or 1 1/2" if using that size angle iron), to each end , and cut for length (Make these measurements slightly fat because you want it snug when installed and a rubber mallet should be necessary to position it).
You then need to box the ends of the angle iron, which is a simple matter of cutting each end right along crease of the angle itself for 1 1/4" (if using 1 1/4" angle iron). I used a cutting wheel on my hand held grinder, but a hack saw would do too. Once this bisecting cut is made, you then simply bend one "tab" down at a 90 degree angle, and fold the other side right on top of it - a hammer will do it. The trick is to end up with a finished piece that is the proper length. Once the ends are boxed and as flat as possible (my vice also has a little anvil area), you must drill a hole at each end, in the center of the newly created box through both "flaps", using a size appropriate for the previously-mentioned bolts to pass through. Well bring this finelycrafted piece back to the garage, test for fit, adjust length with hammer, etc. Next, mark the dead center of the piece, and decide how far out from center your two light units will be mounted, taking care to note a possible clearence problem with the top chrome tube of the guard if you go too far out with big lights (like my Hellas, which I kep just inside of the bends, see the picture). Mark the hole location for the light bracket bolts on the angle iron using equal measurements from center, and after removing the bar drill the proper sized holes for your light mounting bolts. ? Reinstall the bar at either end with bolts to ensure exact position, and drill right through the cladding now using the holes in the bar as a template - but do so only after you have bolted it into place at either end. Also take note of the flat piece of back sheet metal in the center of this area of cladding from our backside view, (GM uses it to keep the cladding from sagging I think) and the piece of sheet metal should end up butting snug into the angle iron piece - the angle iron should be right up against the cladding, and underneath the angle iron should be this piece of metal. I also drilled a smaller hole dead center through this piece of sheet metal and through the angle iron (careful, use a piece of scrap metal behind it so you do not punch through the cladding) of a size that would permit a smaler, flat head machine screw to pass through. ?
Because I hate rust with a passion, I took the angle iron piece back off, primed it and painted it (I had some shinny black laying around, but this thing will never see the light of day). I then reinstalled the angle iron for the last time, using the longer bolts with lock washers at each end and also installing the flat head machine screw (flat head against cladding) through the angle iron and through the piece of sheet metal, with a nut and lock washer at the end of this screw, ?for further rigidity. ?
I installed the guard per directions, and then installed the lights in the holes. But because of access it would be better to install the lights in the bar first (actually you are just installing brackets, leave the lights off until you have wrestled with installing the guard) so that these barckets are very snug and parallel with the front. ?To adjust the light pattern side to side, you can twist these brackets if necessary.
For a look at the installed lights, go to these hastily taken photos:
has held up well for over a month now, although I do notice a very very slight shake in the lights at night - that's why I say go with a beefier piece of angle iron. for me, total cost in parts did not even exceed $10, time spent crafting and installing it, two hours. happy to answer questions.
modified by jackalanche on 12/27 to link to a more recent photo
If you obtain the GM bar for the Av, lay it face down using the cardboard box to protect from scratches, or if you have it on the Av already, detach it and lay it face wond on a few towels. You will see that the two chrome elbows on each side are bolted to the black frame of the guard with two bolts at each of the four tube end attachment points. What I did was I got a 48" length of zinc plated angle iron (Home Depot sells it) in the 1 1/4" size, you could and maybe should go with 1 1/2 " for even more rigidity. ?
I used the aforementioned bolt locations for the top of the bottom tube attachment points, ?that corresponded with attaching a piece of the angle iron cut to fit inside of the two black plates, positioned so the angle is at the top and back (when facing the unit from behind, as we are now), where the top side of the length of the angle iron would lay right up against the underside of the cladding. (remove these two bolts for now, and you will need to buy two bolts and nuts and lock washers about 1/2" longer - also from Home Depot, zinc plated for no rust). Measure this length carefully, note also that it is not a perfect 90 degree joint at the sides, as it flares a bit. Well, using this measurement and erring on the side of being slightly too long, mark the angle iron for length, and add 1 1/4" (or 1 1/2" if using that size angle iron), to each end , and cut for length (Make these measurements slightly fat because you want it snug when installed and a rubber mallet should be necessary to position it).
You then need to box the ends of the angle iron, which is a simple matter of cutting each end right along crease of the angle itself for 1 1/4" (if using 1 1/4" angle iron). I used a cutting wheel on my hand held grinder, but a hack saw would do too. Once this bisecting cut is made, you then simply bend one "tab" down at a 90 degree angle, and fold the other side right on top of it - a hammer will do it. The trick is to end up with a finished piece that is the proper length. Once the ends are boxed and as flat as possible (my vice also has a little anvil area), you must drill a hole at each end, in the center of the newly created box through both "flaps", using a size appropriate for the previously-mentioned bolts to pass through. Well bring this finelycrafted piece back to the garage, test for fit, adjust length with hammer, etc. Next, mark the dead center of the piece, and decide how far out from center your two light units will be mounted, taking care to note a possible clearence problem with the top chrome tube of the guard if you go too far out with big lights (like my Hellas, which I kep just inside of the bends, see the picture). Mark the hole location for the light bracket bolts on the angle iron using equal measurements from center, and after removing the bar drill the proper sized holes for your light mounting bolts. ? Reinstall the bar at either end with bolts to ensure exact position, and drill right through the cladding now using the holes in the bar as a template - but do so only after you have bolted it into place at either end. Also take note of the flat piece of back sheet metal in the center of this area of cladding from our backside view, (GM uses it to keep the cladding from sagging I think) and the piece of sheet metal should end up butting snug into the angle iron piece - the angle iron should be right up against the cladding, and underneath the angle iron should be this piece of metal. I also drilled a smaller hole dead center through this piece of sheet metal and through the angle iron (careful, use a piece of scrap metal behind it so you do not punch through the cladding) of a size that would permit a smaler, flat head machine screw to pass through. ?
Because I hate rust with a passion, I took the angle iron piece back off, primed it and painted it (I had some shinny black laying around, but this thing will never see the light of day). I then reinstalled the angle iron for the last time, using the longer bolts with lock washers at each end and also installing the flat head machine screw (flat head against cladding) through the angle iron and through the piece of sheet metal, with a nut and lock washer at the end of this screw, ?for further rigidity. ?
I installed the guard per directions, and then installed the lights in the holes. But because of access it would be better to install the lights in the bar first (actually you are just installing brackets, leave the lights off until you have wrestled with installing the guard) so that these barckets are very snug and parallel with the front. ?To adjust the light pattern side to side, you can twist these brackets if necessary.
For a look at the installed lights, go to these hastily taken photos:
has held up well for over a month now, although I do notice a very very slight shake in the lights at night - that's why I say go with a beefier piece of angle iron. for me, total cost in parts did not even exceed $10, time spent crafting and installing it, two hours. happy to answer questions.
modified by jackalanche on 12/27 to link to a more recent photo
CJ
. I stopped by the shop last night and the brackets were ready. I have not mounted them yet as I just got them and I plan on powder coating mine before I mount them. 
