KaptainKen

​Had this car for a year without any issues, great vehicle. When we bought it the only blemish to the exterior was a crack on the left (driver's side) of the bumper from a low speed incident. The previous owner had drilled holes on either side of the crack & secured it together with 4 or so zip ties. There was also a couple zip ties on the far bottom corner. It was all done very carefully, the ties were trimmed & it was almost unnoticeable from a few feet away so we forgot about it.
A few days ago while going down the highway at night 3 or 4 of the zip ties broke or wore out, the far left end came lose, started wobbling/flapping back & forth and the low beam headlights stopped working.
High beams still worked so it was carefully limped a few miles with the high beams on.

That piece coming loose caused the wires to be pulled out of the back of the connector to the driver's side side/clearance light. I couldn't get the right connector immediately so I went to trim & tape off the ends but noticed some bare wire a little further up so I trimmed them up to that point and shrank wrapped the ends. Everything I'm seeing seems to point to that circuit not having anything to do with the low beams.

But I can not get the low beams to work.
The high beams work.
The daytime running lights work.
The fog lights work.
The small bulb above the high beams (clearance lights?) and side light on the passenger side works. Neither one does on the driver's side.
The blue indicator on the dash lights up when the switch on the stalk is turned on.

​But NO low beams.

I started with the bulbs, they're fine. Checked all the fuses, they're fine.
Checked the relay (#13) and it tested ok. (Clicked the circuit closed with 12v applied and had .5 ohms or less resistance on the closed circuit. )
​​​​​​Still nothing so I checked every single fuse and swapped some exact same amp ones around to see if anything changed. Nothing.
I got an identical relay to #13 and swapped it out, nothing.
Since I wasn't 100% sure of the exact wiring or if/how the relays interacted I got some identical relays to the others on the block and swapped them out, still nothing.

Those wires go up through the fender under the fuse block. Figured maybe the wires that got yanked out of the light connector were also yanked loose from the bottom of the fuse block maybe (?) taking others with them so since I needed the connector anyways I found a wrecked 03 in a junkyard an hour away, went there, took the fuse block loose & examined the bottom. Nope. Those two wires don't go into the block. They go into the harness that goes halfway across the compartment along the firewall and into the cab.
No way they were pulled loose anywhere, especially inside the cab. And they couldn't have damaged any other connections.

Kind of at a loss here, any suggestions?

Arsenii

Hello,

0.5 ohms is pretty much a short circuit, it will give you about 24 amps of current, and those relays are not designed for such a load, gotta wonder how no fuses got blown when you did it.

The side amber light and a light above the High Beam are powered from the same TAIL relay, which is controlled by the Body ECU. The fact that both marker and fog lights come on with no issues indicates that the column stalk, Body ECU and relays are likely working as intended. Turn on the headlights and use a Test Light to check that you have power coming to the Coil side of the HEAD relay, if so, use a thick wire to jump the Switch side of the relay, after that, use a test light to check if you have power coming and leaving from 15A HEAD RH and HEAD LH fuses, then check if you have power on the headlight pigtails.

If there is power on pigtails, then there is something messed up on the inside of both headlights. If you have power on fuses, but no power on pigtails, then you have a break in the connection between the Fuse Box and your Headlights. If there is no power on the fuses, check that the Switch side of the relay has 12V coming to it, if so, then there is a break in the connection between HEAD fuses and a relay; if there is no power on the Switch side of the relay, then there is no connection between HEAD relay and a 40A MAIN fuse.

Hope this helps and best of luck!

KaptainKen

Thank you so much for all of that, I really appreciate it.

Unfortunately, I DO have power to the fuse, and to the relay, but even if I use a jumper on the relay's circuit there's still no power to either headlight for low beams.

That's what's puzzling me, they're completely different circuits with different colored wires - what could kill both sides?

The Hi Beams work on both sides but not the low beams.

I see there's a separate "Lighting ECU" for left and right, could they both have gone out at the same time? Honestly I'm not 100 % sure what they do exactly.
​​​​​​

LeX2K

Need a wiring diagram otherwise it's mostly guesswork. Closest I have is a 2002 Camry, similar and hopefully will give you some guidance.

https://gofile.io/d/z16YV9

Arsenii

Well, all I could say is that there is an issue in the wiring that runs from the headlights to the fuse box, which likely means that you will have to take the bumper off and inspect the wiring loom behind it. There is one last test you can try though - use a multimeter to check for continuity between headlight pigtail and its respective fuse, if there is none, than there is not much else to do. As for the Lighting ECU in there, to be brutally honest, I am not sure what it is myself..

Why headlights in particular would cut out, I am not sure, it depends on how the wiring is routed in that car. Both headlight wiring, as well as some other stuff likely collects at some point behind the bumper and goes to the fuse box as one complete loom, that would be my best guess.

What I can say, however, is that one of the common issues with my 2000 ES300 is the wiring loom in the trunk was getting frayed, so that lights on the lid would stop working; in my case, both of the reverse lights went out, while the rest of the lights were working just fine. That prompted me to follow my born stupidity and think that those are routed through the light check relay, so I can test the wiring before I will go tear into it. Knowing that my issue is the wiring, I still waste about 3 hours of my life turning my car inside out, trying to find that relay, which ended up being behind a rear seat, only to realize that those wires are not going there..

Hope this helps and best of luck!

KaptainKen

I will post another - correct - reply in a few minutes.

Arsenii

Your explanation seems a little hard to follow.. Can you take a picture of the R-3 relay? The name of each relay in the fuse box should be written fuse box cover as well, to make it easier to understand. My guess is that R-3 is a HEAD Relay, and R-13 is a DRL NO. 2 relay.

As I wrote before, every coil has, what I call, a Coil and a Switch side - Coil is what receives the signal and activates the Relay, Switch is what actually being triggered. Confusing those can and will lead to some unwanted fireworks in the engine bay, so it is crucial to verify what relay are you working with, and what its pins are before proceeding with shorting stuff. For issues like that, where there is a considerable load being placed on the circuit, a preferred way of checking power is by using a Test Light instead of the regular Multimeter, since even the highest quality unit can trick you a bit in this case. Test Light can be obtained at any Car Parts Store for $2-3, if you won't find it, just use a spare light bulb from a taillight or something similar.

In this car, the Relay is controlled via Ground, meaning that it has a Constant 12V supply to one of the Coil pins, where the other is connected to the controls that can complete the circuit by adding Ground to it, therefore activating the Relay. To check that the coil is being activated, put a Test Light across Coil Side pins and turn the headlights on, if the Test Light would light up, then all the controls (switch, ECU and the wiring to the Coil) are working as intended and are not in need of further diagnostics.



As for the Switch side of the Relay, there is 12V coming from the fuse on one of the Pins, and the rest of the circuit that needs to be powered on the other Pin, there is no Ground present, per say. First step is to verify that one of the pins has 12V supply, which in this car is when the Headlight Switch is on. Put a Ground clip of the Test Light to car's chassis, and use its other end to make sure you have power coming in.



One very important aspect before shorting any pins is to verify which set of contacts is which, as I wrote earlier, that can lead to some unexpected misfortunes. Every relay in that car should have a Diagram printed on it somewhere, showing which set of pins is for the Coil, and which is for a Switch, if not, use a multimeter to measure resistance between sets of pins until you find it, which would be your Coil. If you do have 12V coming to the Switch Side, then jump the Switch Side and check if you got any power on the Headlights on on HEAD fuses. If the Coil and Switch are functioning as intended, then it is a faulty relay.

If nothing would change after shorting the Switch, use a Multimeter to check Continuity between HEAD fuses and a HEAD Relay Pin, the one that is not a 12V Supply, which will verify that the wire that is supposed to send power to the Headlights is intact, if not, then it is likely the source of your issue. If that connection is good, check Continuity between the HEAD Fuse and its respective Headlight pigtail.

Hope this helps and best of luck!

KaptainKen

Apologies for that last message, it was very late, I was exhausted & not thinking clearly. This might get a little long but hopefully it'll clear things up.

By the way, I have a multimeter but am doing 99.9% of this with a standard $5 test light.

To check + voltage it's tail is connected to the battery's - Negative Terminal

To check Grounds it's tail is connected to the Battery's + Positive Terminal

And I understand that the relays/relay bays have:
1 - a Coil/Signal wire (lower power) coming in from the switch to activate the electromagnetic coil inside completing the HP (higher power) circuit.
2 - a Switch/Power wire that, when the circuit is completed inside the relay, can supply power to the item.
In this case the Low Beam headlights.

Don't worry, I can clearly differentiate the Signal circuits in the bays from the Switch/Power ones due to the size, thickness and orientations of their respective tab/connections so I'm not just shorting random connections.

I was using a Fuse/Relay Box diagram I believe I found in this forum as a guide, that's why I was referring to "Relay #13" "Relay #3" etc.
In order to avoid confusion I will use the way that they are labeled on the inside of the fuse/relay box cover like "DRL 2" & "DRL 3" from now on.


Here's the current rundown:



NO Low Beams.

High Beams work when switched with momentary ON or full ON.

Both headlight bulbs are brand new & verified as operational.

40 AMP Fuse
is intact and supplying power to the
HEAD Relay.

Both the
15 AMP HEAD RH LWR
15 AMP HEAD LH LWR
fuses are intact.
Bay connections for both have +12 volts.

RELAYS:
HEAD
DRL 2
DRL 3
DRL 4
Are all "bench tested" & operational.
Bench Tested = jumper wires used to apply +12v & Ground to Coil/Signal circuit tabs audibly clicking the contacts closed.
Then with Coil/Signal circuit activated +12v & Ground applied to the Switch/Power tabs to verify current can flow.
I quit trying to measure ohms resistance after the "Deluxe" Harbor Freight multimeter that was on sale pi**ed me off for the last time.

I'm verifying voltage flow through the relays with a jumper & test light now. But I have an accurate Craftsman meter here now if I need it.

HEAD Relay
Has both Coil/Signal and Switch/Power voltage.

HEAD Relay
Verified as operational.

Using a small piece of bailing wire I bent in a specific way to fit exactly without chance of it wiggling or slipping & touching other circuits - I tried momentarily jumping the Switch/Power tabs in the HEAD relay's bay.
NO change.

Initially I understood the instructions kindly provided as meaning that power went directly from the
40 amp fuse to the
HEAD Relay to the
15amp fuses to the
Headlight Connections/Pigtails in the bulb sockets.

But apparently it goes from the HEAD relay to the DRLs.
As I jumped the HEAD relay's Switch/Power circuit & when I plugged it back in I heard one or more of the DRL relays clicking but couldn't identify which one or ones exactly.

So out of curiosity I tried
Jumping the Switch/Power tabs on DRL 2
-- LOW BEAMS CAME ON --





So I would assume that means the wiring from the fuse/relay box to the pigtails is fully intact and 100% functional. (?)

Removed the jumper in DRL 2's Switch/Power connections.
LOW BEAMS OFF.

Replaced DRL 2
NO low beams.
Double checked DRL 2 for Coil/Signal circuit activating the switch and current flow through the Switch/Power verything worked fine.

Tried jumping the Switch/Power slots on DRL 3
No change.

What that means exactly I do not know. What switches/sends Coil/Signal power to the DRL 3 Relay exactly?
Or am I doing something wrong?
I'm having trouble working it out.

Arsenii

Do your Daytime Running Lights work?


That is correct, the power for both Switch and Coil of the HEAD relay is coming from the 40A MAIN fuse, then from the Switch of the Relay, the power travels straight to 15A HEAD RH LWR, 15A HEAD LH LWR and 5A DRL fuse. If you have power Coming and Leaving the 15A headlight fuses, the headlights must turn on, unless there is a damage in the wiring between Fuse Box and Headlights.


The fact that your Low Beams turned ON when you shorted the DRL NO. 2 makes it all even more confusing, since they are not directly related. When the Column Stalk is in OFF position, DRL NO. 2 Relay is turned ON the moment you release the Parking Brake - at that point, this Relay connects both High Beam bulbs in Series to each other, and completes the circuit through the Daytime Running Light Resistor, all that is to make the High Beams work at less than half the brightness, making High Beams act as Running Lights.

When the Column Stalk is switched to Head, the Body ECU disconnects DRL NO. 2 Relay (we will come back to it little later). The ECU also switches the HEAD relay ON, sending power to the Low Beams. The fact is that if the HEAD relay is active (whether it is turned on by the ECU or just shorted), the low beams have to come on. Other than that, there is also a 5A DRL Fuse powered directly from the HEAD Relay - it is there to activate both DRL NO. 3 and DRL NO. 4 at the same time.

Activating DRL NO. 3 causes the RH High Beam Bulb to run in its own circuit with a separate fuse (10A HEAD RH UPR), so that High Beam Lights are no longer connected in Series, and it also leaves out the Daytime Running Light Resistor, so that both lights would work at their full potential. DRL NO. 4 completes the High Beam circuit by supplying Ground to both High Beam Bulbs.

From this point, DRL NO. 2 that we talked about earlier is responsible for the High Beams to come ON, if it is OFF, there is no power supplied to the High Beam Fuses. This raises a question - are you sure it is the Low Beams that come on when you short the Relay? Sorry if it sounds painfully obvious, I just have to make sure.


As far as I could see, all Low Beams need is a HEAD Relay being active, nothing else. Not sure if you have done it already, but try shorting the HEAD Relay and checking if the 15A HEAD RH LWR, 15A HEAD LH LWR Fuses would get powered. If so, it can only mean there is some damage in the Wiring between the Fuse Box and the Headlights themselves. There is nothing in between the HEAD Relay and Low Beams, if that makes sense. You can also try measuring the Continuity between the Low Beam Pigtail and its respective Fuse, if there is none, or the connection has a big resistance, there is damage in the Wiring.

I believed I covered everything, but if not, feel free to ask further questions.

Hope this helps and best of luck!

TRAFIK

did you end up figuring out why ONLY your low beams weren’t working? I’m having the same issue on my 2007 Lexus is350. Fuses, relay, drl’s, high beams work. Just no low beams.

alphasavant34

So I decided to replace all the blubs, turning signals, Parking Light blubs, brake, reverse, headlights low beams and high beams, but now I'm having a problem with my turning signal to the driver side and passenger side for no reason, I have the followings problems and I can't figure out for the life of me what went wrong.

When the lights are not on headlight wise the turn signals turn on as they should but they blink really fast either side i turn on but my 4 ways work as they should, when i turn the headlights on my driver side turn signals will stay solid and I do not know why.

When I unlock or lock the car remote wise I look at the back turn signals and the driver side would blink like it should when unlocking or locking the car however the passager side would not so I was thinking it be the relay and so I took it out and replaced it with the Led Relay that is suppose to support the Led blubs but I found that the original relay is the same voltage as the Led one but I still replaced it but nothing changed it still did the same thing as when I had the old relay in it so I've given up and Will be taking it to the Toyota dealership today to figured out what went wrong and am I still able to upgrade to the Led route that I want too if not I guess I'll just have to revert back to the original route that the car comes as standard. But I was hopping someone here could help me with this problem.

Arsenii

Hello,

What bulbs did you use?

Something like that is a sure sign that one of the Turn Signal bulbs is burned, or has a very low power consumption, like an LED bulb. Shorter blink period is designed specifically to alert the driver that one of the bulbs is fried and in need of a replacement.

Those cars are not even designed to use Turn Signals for the door Lock/Unlock indication, it uses Corner Lights instead, which was a weird surprise when I learned about it. If your car uses Turn Signals, there is a good chance that someone messed with the internal systems of the car, maybe even installed an aftermarket alarm system, which could now be causing the headache you experience.

Can you record a video of the car's illumination system, so that it will be a lot easier to understand what you mean.

Hope this helps and best of luck!