For our purposes, this second wire is the one that goes to the headlights. If power is coming through the wiring harness, replace the headlight bulb and turn on the headlights again. It's also small about the size of a box of matches, hence the name , so it fits easily into just about any headlamp shell. Much as your horns can perform poorly powered through an old switch, so can your headlamp, but with potentially more dire results. I bought some at a local shop that does car alarm installations. Before bolting the cover back on the mounting plate, I used some quick set epoxy on the back of the relays to keep them solidly in place so that the connections didn't wear and so that they didn't rattle around inside a small metal box.
May also consider just buying this, as it's already made and it's plug and play as well. Hook terminal 5 from the remaining relay to the last remaining wire you cut and did not insulate in step 2. Many of these idiosyncrasies are so subtle that you may not even be aware of them. It's really not that hard when you take the time to think about it first. But I couldn't find anything wrong. . The relay acts as an electrical switch that activates and draws power straight from a good fused battery connection and sends it to the lights or accessory.
The procedure I'm writing below uses the colors I have in my 88. So are Buick's and Pontiac's. Ensure a clean rust free connection. With the relay kit, the electrical current travels straight from the battery to the headlight circuit at the fuse box, greatly reducing the load on the headlight switch and the failure prone column switch. It quickly blew both low beam bulbs.
Heat the connector to melt the solder inside the solder sleeve connector. A relay is a switched device that takes the electric load away from the switch and displaces that electrical load onto the relay itself. Scope out the vehicle for the best way to route them. This will help your headlights be as bright as possible. I might bypass my relays for a minute or two just to read the car running voltage of the stock setup. See the lighting diagram below. Most old factory wire was only 12 gauge.
I'm going to assume that you're using your original 3 prong headlight connectors just for ease of writing this procedure. I used 20 gauge wire to handle the increased current. I put in halogen globes and Silverstar bulbs and they work fine granted I haven't been driving the car since, but I have been looking into doing this. Micro relays use a smaller socket then the cube. It's import to say that you should always fuse all circuits. Yellow arrow points to the quick disconnect. Painless Wiring makes a nice weather proof fuse block.
Some smaller wire may be used for smaller connections. Now you've split your hot wire into two hot wires! Depending on your year, you may need to make some adjustments. Most vehicles use several interchangeable relays in the same box; check the number stamped on top to make sure they the same before you start pulling them. The relays I was using came from Radioshack. Turn the headlights on again.
May also consider just buying this, as it's already made and it's plug and play as well. Both my '66 and '68 have this mod. Alternately, you can wedge the handle of a long screwdriver into your ear, and touch the screwdriver point to the relay. You can also check out testimonials from our satisfied customers on our Facebook page or sites like Yelp and Google. While this works, the headlight switch is somewhat under-capable and doesn't supply a true 12V to all of the lighting. Make sure you make your connectors weather proof -- that means sealing any solder or crimp joints with marine-grade shrink tubing which includes adhesive , unless you actually manage to get your hands on a proper, multi-hundred-dollar crimping tool, in which case just crimp and ride. Here's the old voltage regulator housing mounted back up to the core support.
Flickering lights are tiring for you and oncoming traffic and can distract you from what lays ahead on the road. Wiring Headlights and Relays In all basic wiring jobs you need to follow some basic rules of electricity, but it's pretty easy. Most of us are cheap by nature and always looking for low-buck-do-it-yourself upgrades. Of the two relays you're connecting up, one will be used to power the low beam headlight circuit. You could burn up your whole electrical system if you wire in a relay and headlight poorly. They're generally pretty reliable, but will eventually fail with time and use. I have an old Hella relay, and I would prefer to use that to buying a new set with wires and all.