junkref

I have a 2000 RX300 that has relatively low miles (92K) and is in very good condition. The right, passenger side, headlight (high beam) blew out and when I replaced it with the new bulb, it would not light. I swapped out the driver side bulb which is good, but still no success. The old buld was definitely burned out. I checked the fuses, but they all appear OK. Does anyone have any thoughts as to what could be causing this?
Thanks

code58

Junkref- the very 1st thing I would check under those circumstances is the ground to that headlight. I don't have a wiring diagram for your car but MOST cars feed both high beams with 1 circuit and therefore 1 fuse. I have a piece of testing equipment called a Power Probe. It is really handy because you can test for ground as well as hot (and a whole lot of other things!) One way to test for ground with just a test light is to identify the ground wire in the headlight and then hook the test light to + on the battery and probe the ground on that headlight. If the test light lights, you should have good ground, no light, bad ground. It's easy to test electrical with the right test equipment and the car, a very much different thing without access to the car. Wish I could be of more help.

salimshah

The high-beam circuit is a bit complex as it supports DRL [Daylight Running Lights] driving-lights.

Salim

code58

Salim- since I don't have a wiring schematic for the RX I can't check it but do you mean that they are called driving lights (and in fact are) and operate with the high beams and not the low beams? MOST (but obviously not ALL) auxiliary lights are fog lights. As in the case of my F-150 PU they are called fog lights (and I believe are) and are engineered and wired so that if you have them on and turn on high beams, it shuts the fogs off. That would be what you wanted in the case of fog but in the case of driving lights, I assume you would want the additional light of driving lights when you needed high beams (say in the case of country or open road driving in a dark country area where high beams would be applicable). Some won't like this, but I have a personal peeve with people who drive in the city where there's plenty of light and still use the auxiliary lights (whether called driving or fog and are wiring overridden) because they think it's "cool". I have light sensitivity because of a long ago eye injury, and am blinded by some of those unnecessary lights as well as "blinding HID" lights.

salimshah

Fog lights, if aimed properly have a wide and LOW spread. This helps in navigating in fog, by better defining of the road edge for the driver and provide a glow for the on-coming traffic.

The High Beam spread is relatively up, and project further out in distance [hits the oncoming driver]. With 6 light setup, people want to see more light (or all bulbs on ... all hid preferred). Keeping in mind the High Beam is blinding for the driver as the higher up light gets bounced back by fog. So the manufacturers cut out the fog when High Beam is set. [Being mutually exclusive (when fog is present)]. There used to be a law [It may still be there] that you can not have 6 white light sources in the front. [Going on a limb ... at night time, oncoming driver may think there are 2 vehicles]. That is why any auxiliary light that is added to a truck (typically) is listed as "off-road" and you can be cited for having them on, on a public road.

Salim