Today I decided to tackle turning the OEM fog lights into DRLs following the instructions in the Miata.net garage article.
I found the relay under the dash (at least I thought I did) and pulled it free from the mount. I couldn’t figure out how to separate the relay from the connector though. I was going to pop out the red/yellow wire as instructed with its metal end still attached, so I could reverse the mod easy and not have to cut the wire. After struggling for a few minutes I though, what the heck, I’ll cut the wire. First I checked to see if I had some barrel splices to use, I didn’t. I figured I’d wait until I had everything else ready to go before I made a trip to the store.
Next task was to locate a +12v source that is only on when the ignition switch is in the run position. The article mentions he used the radio power wire, but totally fails to mention where it is. Hmmm. There are like 4 other relays in the same area, I don’t know what any of them are for, but one is bound to have a wire that I could use. Turned the key to run and checked for 12 volts. Got one, pink wire. Switched the ignition off, no power, bingo. I even started the car and the 12V goes away while the car is starting. Beautiful. I got a six inch piece of wire and a vampire tap and hooked into my new friend the pink wire.
Seeing as I don’t have any splices I don’t want to cut the red/yellow wire just yet, I’ll try testing it by just pushing my tapped wire into the red/yellow wire connector. I turn the key to run and sure enough there are lights shining on the wall. Yippee. I go around front to admire my handy work and, %@#$, the fogs aren’t on. But the low beams are!?! Now I check to see which page I printed out, as there are instructions in the garage on how to do just this, low beams as DRLs. Nope, I’ve got the right ones. Curious.
Well I wanted DRLS, I got ’em, let’s see if everything else works as advertised. Turn the stalk switch to parking lights and they come on and the lows stay on. Turn the switch to headlights and the lows stay on. With the lights on I hit the fog light switch, they turn on and the lows are still on. Hit the high beams and the fogs go out and the lows are still on.
Cycle thru the routine a couple times. A couple passes through is when I notice that when my new DRLs are on and I turn the headlights on with the switch the light on the wall seems marginally brighter. Can’t really tell how much because it is midday, but definitely brighter. This is something that the folks who have done the lows to DRL conversion complained about. In other cars the DRLs are the lows on reduced voltage so they are not as bright, but the Miata conversion ran the low beams at full power.
Here is where I start to wonder how much current is running through my little 22 gauge jumper. Do I have the right relay? Seeing as the red/yellow wire wasn’t cut, just where was I sending +12v? The instructions said it worked on a 2001 LS, did something change on the 03? So I unhooked the jumper from the red/yellow connector and taped it back. Going to call the dealer tomorrow and see if he will let me copy the fog light circuit diagram…