I'm wiring up two relays for an electric fan (spring) and some driving lights that my friend is integrating into the stock cowl. I needed to run two 22 ga wires from the switches (under the radio) to the relays. The relays are mounted on the passenger side just behind the headlight, there were 3 drilled + tapped holes (+1 for Maz) there. I went to run the wire past the weather boot on the main wiring bundle on the passenger side. Low and behold there was an extra nipple on that boot, just clip the end of and there is a clean weatherproofed hole for an extra few wires to run through(+2 Mazda).

The only real problem with this install is that I tapped power for the switches from the radio wiring harness. It was there, I upgraded over xmas so I knew which wire I needed, and I could yank it and do a proper soldered connection. Unfortunately when I hit the switch to fire the relay, my stereo dies (-1 Murph). I think the switch circuit or the indicator light is acting like a short. Any ideas on where else I can tap power from?? Running a second wire wouldn't be too hard, but I'd rather not.

 

whoa bro just find a power wire from somewhere. any wire. you also have to do the wiring correct.

 

Perhaps some more info would yield a more helpful response.

Its wired so that the positive power wire runs to the positive side of an indicator LED and to one post of my switch. The other side of the LED is grounded. The other post on my switch is wired to the trigger terminal on my relay. The ground terminal on the relay is wired to a convienient bolt.

The relay and LED are only supposed to draw 160mA and 20mA, respectively. Even assuming I got ones that are way out of spec, they won't draw any more than half an amp.

My lights havent shown up yet, so really all its doing right now is tripping the relay. When I hit the switch, the relay does trip and my indicator LED comes on. I checked with my multimeter both on and off.

I'm going to go tinker with it a bit more, but the only things I can think of that would be a problem are that:

1) There is such a low resistance in the circuit that its acting like its grounding out.
2) The LED is grounding out. I didn't wire it in series because the LED is rated at 20mA and the trigger side of the relay is going to pull more than that and would roast the LED.
3) There needs to be a load on the relay for it to work correctly. I'll test that first.

Any ideas??