Relayed headlights - strange behavior - (removed) is going on?

wyldejackyl · Post by **wyldejackyl** » Sun Jan 25, 2009 9:47 pm

I finally got around to relaying my headlights. The car already has 135k on it and I can't justify spending the $$ to put in HID's, so I got a nice set of ultrabright H4 bulbs, and went to work. I installed 10ga wiring right from the alternator to a pair of relays I mounted where the intake air muffler was (behind DS headlight, next to the battery on the fender wall). I got two new female ceramic plugs for the headlights, and have those switched off the relays. Relay current comes from a male H4 connector I wired to the DS headlight socket (that way I could restore it to stock later on if necessary). My thought was, when the headlights were receiving current from the respective pin on the connector, it would switch the relays and operate the lights that way. I've noticed an increase in performance, even on the lower-wattage filament of the bulb. But here's the rub: When it's hooked up right, when I turn the headlights on at normal brightness, I get both filaments on. When I turn just the brights on, it turns on just the lower filament. When I invert the wiring, so the relays are backwards (lo is hi, hi is low), I can operate the switch backwards and it works okay (where my "brights" are on, they are actually my low beams), but the blue light on the dash is on, but very dim. This has to have something to do with the damn DRL box under the driver's side dash. I already have the yellow wire grounded to disable the DRLs. Is there a diode and resistor I need to stick someplace to fake a load, now that the relays are taking the place of the stock light harnesses, and they draw hardly any current?

Sublimewind · Post by **Sublimewind** » Mon Jan 26, 2009 2:44 am

what is the wattage of the bulbs you bought? I mean stock is 55/85w low/high.. did you get something like a 85/135w set-up? If not, it's not likely you even needed the extra wiring.. also, when you said you wired right to the alt, do you mean RIGHT TO THE ALT? If so, you might not be benifiting from the filtering that the battery does (longshot here, as the alt is directly on the batt as well)

wyldejackyl · Post by **wyldejackyl** » Mon Jan 26, 2009 6:35 am

Stock wattage is 55/60. The ones I bought are 55/100. I may go even higher eventually, which is why I used ceramic harnesses to hook up the bulbs themselves, and 10 gauge wiring."Right to the alt" means "right to the alt" as in "ring terminal right on the terminal lug." I'm not worrying about any filtering effect the battery has, as there's already a voltage regulator, and that's on the bulb side of the circuit. The problem is definitely on the relay coil side. It has to be something to do with the DRL box sensing not enough load. Keep in mind the relays take a few mA to trigger them, while bulbs have a load on low of what, 3-4 amps? 24 or so on high, for both? That's a huge difference, but I'm guessing there's a threshold someplace of 1-10ohms. I'm just guessing - if I knew the answer, I wouldn't be asking you guys.

Sublimewind · Post by **Sublimewind** » Tue Jan 27, 2009 1:56 am

I've never really dug into my vibes electrical, so I can't help you with the DRL situation, seems plausable though...