Dead headlights - 2000 Eclipse

I assume the bulbs are good? The relay is in the engine bay.

Well, here's how your car works. You turn on the light switch on the steering column. This switch tells the column ECU that you want the headlights on. The column ECU tells the ETACS ECU to turn on the lights. The ETACS ECU tells the engine compartment ECU to operate the relay, to turn on the head lights. The relay (there are two, one for high beam and one for low beam) is located in the "relay box" mounted on the left front fender, but, if I read the service manual correctly, the relays are located inside the engine compartment ECU box (located in the engine compartment relay box, beside the fuses). In fact I just went outside and looked, and there appears to be no relays in the relay box, for the headlights. Please note that there are four fuses for the headlights, one each for low/high beam on each side.

I have to assume the bulbs are good. It's HIGHLY unlikely they would both fail at once and both have high and low beams go at once. I also checked all four fuses.

From what you say, it sounds like the steering column switch is a single pole device simply telling the ECU "it's headlight time". And that in turn tells all the other "headlight" related electronics to do their thing. If that IS true, then I think the steering wheel switch and it's ECU are ok as the marker lights come on. Also I can turn on the fog lamps. That too is an indication of the steering wheel switch being OK since that switch must be on BEFORE you can turn on the fog lamps.

From the service manual is it obvious if the steering wheel switch is just a single pole device, or does it have three poles, one for the headlights, one for the marker lights and one for power to the fog lamp switch?

Thanks, Gary

"Nirodac Yar" wrote:

I once had an '82 Corona that did exactly the same thing. It was the headlight relay. FWIW YMMV DFB

"When a legislature undertakes to proscribe the exercise of a citizen's constitutional rights it acts lawlessly and the citizen can take matters into his own hands and proceed on the basis that such a law is no law at all."

- Justice William O. Douglas

The wiring diagram shows four switches in the steering column, feeding a ground signal into the column ECU. Switch one, is listed as "Head, on/off" Switch two, is listed as "Tail, on/off" Switch three, is listed as "Lo-Hi" Switch four, is listed as "Dimmer-passing"

The fog light switch feeds directly into the ETACS ECU. so it's the ETAC module that decides when the fog lights come on.

If someone turns the headlights switch on and off, can you, in the engine compartment, with ear close to the relay box, here the relay operate.

Thanks!!! The first three make sense not sure what #4 is though.

I haven't tried listening for the relay yet. Are you sure it will make a sound? Some of the old solid state relays I've used in some electronics were totally silent.

One more thing. Can you, or anyone else, tell me specifically which relay is the headlight one? I can easily pull and test it if I know which one it is.

Thanks again,

Gary Shell

"Nirodac Yar" wrote:

#4 is for "flicking" your lights between low and high beam just before passing someone, I think.

Don't know if you can here the relay or not. The schematic shows it as a coil and a set of contacts. I don't believe the engine ECU is potted, you could probably pop the cover off and see the relay operate (just a guess)

Also on further examination, the schematic shows a violet coloured wire running from the column switch that turns the headlights on. This wire should have a ground on it when the lights are on. It runs to the front ECU unit (as well as the column ECU) in the engine compartment. There are protection diodes in the colum switch (Cathode on ground side) so if you use an ohm meter, get it right or you won't messure anything.

snipped-for-privacy@fuse.net wrote in news: snipped-for-privacy@4ax.com:

Thanks once again!!!

Gary

Nirodac wrote:

very strange indeed! the same thing happened to me with my colt (mirage in US) a few weeks ago.i first checked the fuses and then the bulbs (which are unlikely to break both at once).i also disconnected the "lead" from the bulbs a few times to make sure the connection is not corroded, still nothing. then i turned on the high beam a few times and suddenly low beam worked as well again.very strange, i have no explanation for this exept it may be good to disconnect and re-connect everything (i.e. fuses, connector between lead and bulb, etc) once a time since it can be corroded or rusty.

my only advice is to try this out before buying new parts.

good luck j.

I had a problem like that, turned out to be the switch itself.