Fog Light/Driving Light Installation
When I first
got my Miata, I noticed that it did not have Fog/Driving Lights on it. I knew
that this was an option on some Miatas, but I did not know what years, where the
lights mounted, etc. After doing some research on Miata.net, I found that the
wiring, at least part of it, was already in place. I also found that a factory
switch could be purchased that was a combination Fog/Driving Light/Rear Defogger
switch and would fit into the dash. The pre-installed wiring was a
"hot" wire incoming (red/black) from the headlight switch, and an
outbound wire (green/yellow) that terminated with a "bullet"
connector, and was tied up under the fuse panel in the engine compartment on the
driver's side. In further reading and checking, I found that the power to the
Fog/Driving Light switch was only active when the low beam headlights were on
and went off with the high beam headlights. This meant that I could only use the
For/Driving Lights with the headlights on (barn doors open). This I found odd,
as on my 1998 Dodge Dakota I just have to have the Parking lights or the low beam
headlights on and the Fog/Driving Lights will come on and they will go out when
the high beam headlights are activated. This is what I wanted on the Miata. So I
had to find a way to make it work. Thank goodness for Chrysler. When I installed
the Fog/Driving Lights on my Dakota, a complete wiring diagram was included.
That is what I used for the Miata, and it is shown in the photo section. This diagram indicates
the wires on my 1995 Miata that I tapped into (other years may be different). I
disconnected the factory input to the Factory Fog/Driving Light switch and used
my own. I tapped into the Park light wire for the power. I also tapped into the
High Beam headlight wire. When energized this will shut off the Fog/Driving
lights. The relays were another matter. For the normally closed relay I used one
that I got at my local electrical parts dealer. They sell it as a
"horn" relay, But it is a five-pole with a normal closed side. When
energized it will trip the switch and provide power to a different terminal (87)
that you do not connect to anything. To be
technical it is a Double Pole/Single Throw relay. Chrysler uses a Siemens Relay
- Chrysler Part No. 4671168. They cost about $22 at a Chrysler Dealer - but at a
wrecking yard they are probably cheaper. For the normally open relay I
used a standard lighting relay available at most auto parts stores for $5 or $6.
You could also use the same relay (normally closed) and use connection points 87
and 30. I mounted the relays on the firewall in behind the brake master cylinder
in to holes that already existed in the firewall. this keeps the relays out of
the way. I later found sockets to mount them in rather than using the crimp
spade connectors. It gives it a move finished look, and if you need to replace a
relay, unplug the old and plug in the new.
For the Fog/Driving Lights I used some Pilot PL-1074W with blue lenses and H3 bulbs. They are 5 inches wide and 1 7/8 inches tall. Picked them up at Auto Zone for $20. I mounted them in the mouth of the Miata near where the tie down hooks are initially. I then made a grill of 13 Gauge extruded steel - trimmed the bottom edge with Door Edge Guard. I used two existing bolts to hold the grill in. I bolted the Fog Lights to the grill. I killed two birds with one idea - grill and Fog Light mounting.