1st gen headlight electrical issues, no Lo beams, no Hi beam indicator

I have an 04, 2wd, extra cab, automatic, and no power anything except steering and brakes. I have used the daytime running lights for most of the past two years. A few weeks ago, I started having headlight problems: the headlights work on what appears to be low beam in the high beam switch position. The high beam indicator does not work at all. and the low beam position on the switch has no working headlights. The momentary position (pull back) lights low beams. So low beams work on Hi beam setting, dash indicator does not work at all, and there are no high beams. It about has to be a fuse or a relay, but I am not having any luck tracking it down. I have replaced the headlight relay in the fuse box left side of engine compartment, and the switch so far, and neither of them solved the problem. I haven't found any blown fuses and have checked most of them. The two power outlets also seem to be not working (may be a separate problem.) All the other lights (tail, marker,turn) work normally, just no Lo beam headlights. I am looking for the main daytime running light relay that is supposed to be just to the right of the steering column, but it does not appear to be there. I am assuming that the daytime running lights are the function that turns the headlights off when the driver door is opened and the ignition is off. Any thoughts or does anybody have a picture of the DRL relay in the wild? Thanks, Chip

 

Daytime running lights are just that, it turns the headlights on at a lower brightness during the day when the headlights would normally be off.

The main DRL Relay is more of a module than a relay, it has a 20 pin connector. Best I can tell from the diagrams it's in the center of the dash.

The power outlets not working I bet is a blown PWR OUTLET fuse.

 

Hey Dm93, Thanks for the schematics. The only ones I could find were from 01 and they were blurry when I DL them. This will make tracing it a lot easier. What happened to the old days when it was battery, fuse, switch, headlights. This looks like some engineers had way too much time on their hands. Does it appear that the DRL module is to the right of the emergency brake lever? I pulled off the lower dash panel from the left over to the emergency brake and there isn't anything there with that many wires going into it. Is it behind the console? Thanks!

 

Yea I'm not sure why the 1st gens with DRL have such a complicated headlight circuit, 2nd gens are much simpler. Still way simpler than modern vehicles.

I'm not sure, I don't have alot of knowledge about 1st gens I'm just going by the location diagrams.
I can poke around in service info some more later when the power comes back on and see what else I can find out about it, we just had a little thunderstorm here and the power is out at the moment.

 

I believe that I am confused about what daytime running lights are: I turn on my regular headlights and they go off automatically when I turn the vehicle off and exit the drivers door. That is what I thought DRLs were. It appears that the DRLs are just turning on the "parking" lights, not the headlights. If DRLs were the regular headlights how would the vehicle know when it is day or night, without some kind of sensor? Apparently that is what some vehicles actually have is a sensor that turns on the lights during the daytime. But, again, it is the parking lights, not the headlights. So, I need a schematic for an 04 without DRL. Can anybody help me out? Thanks!

 

It depends on the vehicle, some use the front amber lights but most use the headlights. This is totally separate from headlights turning on and off automatically, some vehicles you can turn the daytime running lights off but others they are on all the time whether you like it or not.
The auto turn off feature is a function inside the Body ECU, it is separate from the DRL system (if equipped).

1st gen (95-04) Tacomas with DRL used the headlights on a lower brightness, 2nd gens used the front amber turn signal bulbs for DRL, and 3rd gens use either the front amber turn signals or on the higher end ones the LED halo strips.

Below is the diagram for non DRL equipped trucks, it's much simpler.
The easiest way to tell which system you have is going to be looking at your fuse layout, DRL equipped trucks will have 4 headlight fuses (HEAD (LO LH), HEAD (LO RH), HEAD (HI LH), & HEAD (HI RH)), a DRL fuse, a DIMMER Relay, and a HEAD Relay.
Non DRL trucks will have just 2 headlight fuses (HEAD LH & HEAD RH) and a single HEAD Relay.

 

Dm, again, thanks for the schematic. This is a lot simpler than with the DRLs. In fact, it looks like if the left headlight is burnt out, it could do what I am seeing. I will check it out and post the results. Thanks a bunch.

 

Well this has been a learning experience. For posterity, here is how it worked out: Firstly, in case you are not aware of it, you are not supposed to touch the glass part of modern automotive headlight bulbs, handle by the metal parts only. Apparently the oil from your skin will cause the bulbs to burn out prematurely. This is germane as both of my low beam filaments burnt out at the same time. I had just replaced them about 8 months ago with premium bulbs, but I handled them by the glass part. Two burnt out low beams is what caused the symptoms that I was seeing. Essentially, the power goes from battery through the "HEAD" relay in the fuse box, under the hood, through a fuse (R & L) to each headlight. The relay is activated through the body ECU. Power then goes through the bulb filament (hi or lo) and joins with the output of the other headlight one common for the Hi filaments and one common for the Lo filaments. The position on the combination switch makes the appropriate ground to light the appropriate filament. The Lo beam power also lights the Hi beam indicator on the dash. So no power going through (at least one) Lo beam filament, no Hi beam indicator. That was the problem, well one of the problems. The other one is that the new relay that I ordered through my local parts supplier was defective and did not work. The original one tested good, so I put it back in. Word to the wise, check your new parts to be sure they do what they are supposed to do. Hope this saves somebody a lot of googling and probing time. There are a lot of Tacoma headlight problems out there, some of them pretty scary ($$$). I lucked out and all it cost me was two new headlight bulbs, a used combination switch off fleabay and about 10 hours of studying and probing. Big thanks to Dm93, I couldn't have done it without you, buddy.

 

Yea never touch the glass on a headlight bulb, if you do it can cause them to fail prematurely.
Wouldn't be the first time I've seen multiple bad bulbs, I've had a vehicle at the shop with 6 bad bulbs before (compliant was no tail lights).