I am currently in the middle of a side marker mod to wire LEDs in place of the bulbs but am a bit stumped. I am attempting to attach wires to the +/- metal contacts located in the interior of the bulb housing (see below). Soldering does not seem to work as the solder will not sit on the contacts (instead it hardens and just falls off as a solid bead without attaching to the contact). Is there something that I am doing wrong? If not, can someone well-versed in this area suggest an alternative to attaching the wires to the contacts? Input is much appreciated. Thanks!