How To Install and Wire Auxiliary Lights

by Dave Haworth

It’s not important for RallyCross, but if you plan on doing unpaved or winter night TSD rallies, auxiliary lighting can be very helpful. For that matter, maybe you drive back roads on occasion and you would like a little help from some extra lighting. Whatever your particular need, the first step in adding auxiliary lights is to decide what you want to accomplish with adding lights to your car. I am sure there are far more options than what I am going to discuss here, and I readily admit I am far from being an expert. I am sharing my install in hopes that it may help others. If you have plenty of experience with adding lights, please feel free to contribute in the comment section.

Back to deciding what you want to accomplish with adding lights … and what type of budget you are allocating towards your lighting project. The two most common light sources are Halogen and Xexon (HID). The HID lights are brighter and crisper, but come at a higher cost than the Halogen lights. I am working within a fairly tight budget, and thus decided on Halogen lights.

I opted for the Halogen lights because of cost, my frequency use, how I plan to use them and for the speeds at which I will be using them. I am primarily adding lights for use on unpaved and/or winter TSD rallies. People who are driving at higher speeds, such as the stage rally participants will surely want to consider the HID lights.

In addition to deciding on the light source, you’ll need to decide on what type of light you will need to use to accomplish your lighting needs. The common choices are fog lights, driving lights, and spot (pencil beam) lights. The difference in the lights can be summed up as to their beam range and beam shape.

• Fog lights – provide a wide (bar) shaped beam that has a short-range. Typically, they will be mounted and aimed low. Bulb color can either be yellow, white or of a blue hue. They are intended to be used at low speeds to help with visibility in fog, rain, dust or snow.
• Driving lights – (or off-road lights) offer a beam pattern that is conical much like your high-beams, though they typically have a range greater than your high-beams. Caution:In many states, it may be illegal to use these lights when “on-road” (public paved roads) and/or they may be required to be installed in a way that ties them in with tripping off the high-beams. Before purchasing any auxiliary lights for your car, I highly recommend you check your local laws about installing and operating auxiliary lighting.
• Spot (pencil beam) lights - have a beam that is very narrow in comparison to the other lights and offer very long-range. The most common use would be for people who are racing off-road at high speeds. The caution above applies to these lights as well.

If you’re not totally sure what your light needs will be or how to achieve that goal, I would strongly recommend contacting someone who specializes in this area. For me that was Primitive Racing, who specialize in preparing rally and race vehicles, as well as being a great source for performance parts. After consulting with Paul and Blake, I acquired my lights through Primitive Racing.

Considering my lighting needs for unpaved/winter gravel rallies, I opted for a set of fog lights and a set of driving lights. The fogs will be useful for poor weather and dusty conditions, as well as helping to see the sides of the road and for cornering. The driving lights will be useful for more light and further visibility on those dark back roads.

Now that we know what we want to achieve with the lights in order to accomplish our lighting goals; we now have to decide where we are going to mount the lights. Once again I must caution you should check with local laws to see if there are any mounting restrictions (i.e. how many lights may you mount, how high or low they can be, etc.).

Older cars seem to offer more mounting options, especially when they have steel bumpers. When it comes to newer cars … mounting can be a challenge. Often light bars (or light pods) are the only option, and then finding a good hard point to attache the light bar may still be a challenge. Fortunately, I had a fantastic resource in helping me make this decision. The guys at Primitive Racing fabricated and installed a light bar for my 2011 Ford Fiesta.

Once you decide how to mount the lights, go ahead and mount them for that little bit of a sense of accomplishment. You’ll need the little victories, because installing auxiliary lighting (done properly) takes a bit of patience. This was the hard part for me because I totally lack patience.

Now that we have the lights installed its time to tackle the hard part of the job … wiring up the lights. Most light kits come with a wiring harnesses which will make your job easier. After having wired up the two sets of  lights, some companies definitely have better wiring harnesses than others. The PIAA wiring harness was nice. I’ll definitely consider that when purchasing future light kits, plus their self-sticking switch is really nice. Though if you want to pay a bit more some light kits have remotes for the switches, which means you only have to do the under-hood wiring. Something to definitely consider.

The other thing I debated when deciding on how I wanted to wire the lights was whether I wanted the lights to be independent or triggered on/off by turning on/off the high-beams. In other words, did I want them to come on when I flipped the switch or did I want the driving lights to turn on with the high-beams and off when I switched back to my low beams. Did I want the fogs lights to turn off when I flipped on the high-beams, so they only worked with the low-beams.

In regards to the driving lights: Oregon law states they need to be tied into the high-beam switch so they only come on with the high-beams and when you turn off your high-beams the driving lights kick out. Some people feel that you should use a three-way switch so they can operate as previously mentioned or independently. If you decide to go that route you are looking at using a toggle or rocker switch, which you’ll have to mount into the dash or fabricate a switch plate. My thoughts were that I couldn’t imagine a situation where I would want the driving lights on without the OEM high-beams being on. I did wire them to trigger on/off with the high-beams which we’ll discuss shortly.

As for the fog lights, I decided to wire them independently. My thoughts were, I could see me using the driving lights off-road, but I still would like to have the added benefit of side illumination from the fogs being on.

Before you actually start wiring, I would strongly suggest pre-planning your wiring route. I found it very helpful to plan from where you want to place the switches, back to the lights. I consulted Paul Eklund, owner of Primitive Racing, on where he, as a very experienced rally driver, would place the switches in the Fiesta. He had a very important point, that I had not thought of as I was planning; put the light switches in a place that the navigator can reach them for the instance when you have your hands full driving, you can ask them to turn on or off the lights.

For the Ford Fiesta, we thought the best place was on either side of the “Passenger Airbag Off” warning light, providing you were using self-sticking light switches, such as the PIAA switches. The switch I got in the Hella wiring harness was not self-sticking, it was the type that you would have to drill a hole in the dash to install or fabricate a switch plate. I wasn’t going for the drilling the dash option, and I really liked the look and the ease of install for the PIAA switches. I decided not to use the Hella switch and on Paul’s recommendation, we ordered another PIAA switch to wire into the Hella wiring harness.

After deciding where I would put the switches, the next thing I had to consider is do I need power for the switches. You probably will, so you’ll want the path of the wiring to go towards the internal fuse box. In the Fiesta, the fuse box is behind the glove box, so my wiring is going to go out the passenger side. How are you going to draw this power from the fuse box? Tap into a wire of an existing fuse? I decided to use a fuse tap, to a fuse that does not have power when the ignition is turned off.

When using a fuse tap, you remove the original fuse and insert the fuse tap, which has blades like a fuse into the fuse slot. You’ll put the original fuse in the fuse tap, plus another similar fuse in the fuse tap for the source you are going to wire to the fuse tap lead. Be sure to pick a fuse slot that has the same amps as what you are wiring into the system. Click the picture for a larger view of a fuse tap, which I found at Autozone.

I now know that I am going to need to tap into the internal fuse box, which has prescribed me going out the passenger side with the wires. I’ll next need to find a route out of the inside of the car to the engine compartment. Some would say drill a hole through the fire wall. Easier said than done with newer cars. Plus that may cause issues of its own down the road. I didn’t want to go through the firewall. I also wanted my wiring to be as clean and inconspicuous as possible. Fortunately the Ford Fiesta has a grommet on both sides that would be useful for bringing wires in or out of the interior. Grab a wire coat hanger or something similar to poke around to find the route for the wires. I pulled the grommet out so it was easier to fish the coat wire through. It is worth noting I couldn’t find a clean route from sticking the coat hanger down from the outside into the car. But when trying from inside the car to out, I found a clean route to the grommet hole. Once you get the wire through the hole, leave it there for now. DO NOT PULL IT OUT!

We now have a route from inside the car to the engine compartment. Things that need to be considered now are; we need to get power from the battery, we need a place for a ground wire and we need a place to install the relays. In my case the battery of the Fiesta is on the driver side of the car dictating the wires be run back across the car within the engine compartment. It was very difficult to find a place within the stock Fiesta engine compartment to attach the relays. I decided to use small self-tapping screws to attach my two relays to the battery holder box.

This worked out though, because it got me closer to the battery for main power to the lights, which needs to come off the positive battery terminal.

It also put me right in the vicinity of the factory ground wire location.

And that is right next to the engine compartment fuse box, which is what I would need to tap the driving lights into the high-beam operation. There are a couple of ways to tap your driving lights into the high-beam loop, so that the driving lights come on (when the internal switch is in the ‘on’ position) when you flip on the high-beams. Some people locate one of the wires coming from the high-beams and piggy-back off of that. I decided to use a fuse tap for one of the high-beam fuses. This eliminated the need to have to locate the proper wire to the high-beam lights, which is easier said than done on some cars.

From here you need to find a route to the lights themselves, which usually means you’ll run the wires along the side of the engine compartment around to the front of the car above the grill, then down and out through the grill to the lights. Be sure your wires are free and clear of the radiator fan and all other moving parts within the engine compartment. Once the wires are through the grill, you can run to the lights and wire the lights up.

I almost forgot to mention, because I just assume it is known; BEFORE YOU START RUNNING YOUR WIRES, DISCONNECT THE BATTERY.

We have a plan of attack, as to the route we are going to run the wires. Make sure you have all the tools and materials you’ll need for the job (i.e. wiring tool – stripper, connectors, extra wire, electrical tape, zip ties, wiring loom, etc.). Once you got everything you need you are ready to start running the wires through the planned route.

Remember I said to leave the wire coat hanger (or similar item) through the route into the interior of the car? Depending on which way you are going to run/pull the wires (it is better to pull) attach your wires to the trailing end by bending the coat hanger around the wires and wrap the wires with tape so you can pull it through the grommet hole without damaging the wires. It is easier if you have one person pull slowly, while another person slowly feeds the wire from the other end.

Once you get all the wires run and connected, re-hookup the battery and test to see if all the lights are operating correctly. Provided everything works as intended, it’s time to clean up your wires by zip-tying them out-of-the-way of all moving parts and to ensure they aren’t flapping around the engine compartment. Where possible, use wiring loom to cover the wires. It will protect them and it puts a more professional looking finish on the project.

I used a modified version of the below wiring diagram. The difference being I only fuse tapped into one of the high-beam fuses and I used a two-switch instead of a three-way switch.

I’d like to thank Paul Eklund and Blake Lind at Primitive Racing for helping me with this project!

February 26, 2012 | Categories: How-To | Tags: All night rally, Auxiliary Lights, Dirty Cones and Checkpoints, Gravel Rally, Hella, How to install, PIAA, Rally, RallyCross, Rallysport, RallyX, Road Rally, Winter Rally | 4 Comments »