i decided to trace my headlight wiring out. it is wired pretty strangely. there are two relays but not as i would have wired them. i checked the voltages in and out of the power relays (2 of them). there was a .5-.6 volt drop across the relay with the engine running at fast idle and the headlights on. that isnt right. so i got a couple of new relays and put them in. no voltage drop at all there. so i gained 1/2 volt just from replacing both relays. the old ones must have been pitted and i bet they were original.
1/2 volt picks up about 12% in additional lumens.
it is easy to check. the relays are behind the passenger electrical kick panel in front of the passenger seat. remove the cover. on mine there are rows of relays. just pry the two lighting relays out enough where you can get a voltmeter probe on the terminals while it is still in the socket enough to work. do all of your measurements with the engine running at fast idle and the headlights initially on low beam
then measure the voltage on the 12v bus to see what the starting voltage is. then measure at the incoming terminal on the relay. on mine that was the one facing front or #30 on the relay. then measure the outgoing power on the relay (back one and #87 on the relay on mine). there should be no voltage drop between the two pins.
the other relay on mine is the hi/low beam and is triggered when the high beam is on. same thing there but check with high beam on. there will be less voltage on both because of more current draw with all 4 lights on, but it should be the same on both pins again.
i know everyone is hung up on only using hella or tyco (formerly bosch) relays, but i have used radioshack ones with no issues. and they were only 5 bucks. they are the standard 4 pin auto relay at 40 amps.
now to get the new lamps and brighter bulbs.....
i like to drive at night and love to have bright headlights.
tom
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