Lighting Installation - Installing the Headlamp Relays
Once I had the parts for the relay kit - including the various new bulbs and the replacement headlamps - I began the setup and installation. First order of business was to lay out all of the pieces so I could better visualize just what I'd need in terms of wiring and how everything would fit under the hood. As Stern notes on his site, the relay kit comes with all of the necessary connectors but no wire - that's more easily and cheaply found locally. In my case at the local Radio Shack and Napa Auto Parts stores. I ended up doing things a bit differently than originally planned - I opted not to use the auxiliary fuse block for the headlamp relays - the one bit of wiring Stern includes in his kit is a very nice heavy-gauge fused connector setup for powering the relays directly from the battery or alternator (that's the reddish wiring in a loop in the picture on the left below - you cut that wire in the middle to attach connectors to either end). The other change I made was to not ground the headlamps immediately at the mounting point. Rather, I ran ground wires back to a new ground bus (more on that below).
After laying things out and measuring twice I cut my wires to length, soldered the connectors to the ends, bundled them up and put the bundles in some wiring loom covers so they'd look nice. Here are pictures of the relay kit components and the completed wiring harnesses for the two headlamps. I'll take a moment here to note the very high quality of the components supplied by Mr Stern. The relays are excellent as are the various connectors - including the high-heat ceramic H4 connectors for the new lamps.
The next step was to install everything under the hood. I opted to locate the relays near the auxiliary fuse block on top of the right-hand wheel-well. I left about a half-inch of space beneath the relay mounting blocks to ensure adequate clearance for the wiring. Snaking the two harnesses through the grill assembly was simple enough - there was a conveniently large hole already there. Removing the old headlamps and pulling the wires through to attach to the new bulbs took about ten minutes per lamp. I made sure to use some wire ties to run the driver's-side harness alongside the existing (original) headlamp wiring harness, keeping it out of harm's way and essentially invisible from the front of the vehicle.
Everything snaked into place I proceeded to make all of the connections (negative battery cable disconnected of course).
The second deviation from my original wiring diagram involved installing a ground bus that can be used by both the headlamp setup and also the auxiliary fus block (and anything else I throw under the hood). I simply attached a ground bar from a household circuit breaker box and ran a 10 gauge wire from one end directly to the negative terminal on the battery. Other ground wires are simply attached to the bar. Here's a close-up view of the ground bar and another angle on the relay setup and its connection to the ground bar.
Once all the wiring was in place the last order of business was to reconnect the battery and fire things up! Everything worked exactly as expected - and the headlamps are much brighter than the old ones. Last thing to do is re-aim the headlamps and this project is complete!