I just installed the PIAA 400/500Hz set on my 2012 Leaf. Together they pull about 8 amps according to specifications. I was willing to pay a little extra for them (made in Japan) in the hopes that the job won't have to be re-done in the future. Making the 2 sets of power splitters (one for ground, one for +12V) was probably the slowest part of the job, but next time it won't be
. I bought some beautiful insulated disconnects, and then had to carefully chop off half of the insulation on the male disconnects, using a box cutter. It looks pretty nice now that it is all put together, with no exposed wiring and no modification of existing wiring.
I used some red 14 gauge wire for the positive leads, but if it is visible from the front of the car, I will replace the red wire harness with a black one I made using the leftover wire from the PIAA kit. Either way I'll probably donate the extra power splitter to someone at the Bay Area Leaf owners meeting July 14. I almost have a second spare splitter made up, just need to get a couple more female 18 gauge fully insulated 1/4 inch disconnects to finish it. Some lucky person will avoid the trip to the store with new horn in hand to check the fit of the connectors... plus wiring harness assembly time.
Thanks to this thread, I put a rag down to keep stuff from falling under the radiator. I was almost certainly saved from half an hour of fishing around for bolts.
I accessed the horn from the top. I have long arms so it wasn't too hard to reach.
Here's the optimal parts list for installing dual horns that draw 8 amps or less. If I ever have to do it again, I'll be able to look up my posting here
. Note that the PIAA kit comes with 2 ground wires about a foot long, with a female fully insulated disconnect on one end, and a spade lug on the other. Chop off the spade lugs, cut both wires in half, and you have your 4 pieces of 18 gauge wire with 2 fully insulated female disconnects already installed.
Optimal parts list for dual horn installation (access via coolant reservoir)
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18 gauge stranded wire (about 2 feet of wire, cut into four 6-inch pieces)
2 male disconnects, 1/4 inch (6.4 mm), for 14-16 gauge wire (you will stuff two 18-gauge wires in each of these)
4 female disconnects, 1/4 inch (6.4 mm), for 18 gauge wire, fully insulated (14-16 gauge will work but isn't optimal)
wire stripper for 18 gauge wire (or a sharp knife)
crimper (often included with the wire stripper)
10mm socket with long extension bar (for removing the coolant reservoir, extension to avoid clobbering headlight)
12mm socket with short extension bar (for the horn)
flat-bladed screwdriver for popping the plastic fasteners on the apron above the radiator