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Headlights not working (except for "manual" flash of high beams)
I am having an issue with my 92 Toy DLX 22-RE 4wd trucks lights. Have tried searching here (and elsewhere, and google- w/o finding a case that met my parameters)
So- this past week I discovered my headlights would not work. BUT- they would work IF I pulled back on the light switch (ie: flashing my high beams. So the bulbs themselves are not blown). And for a few days they basically worked intermittently. Sometimes turning them on/off, sometimes several times, got them working, and sometimes they just worked.
Also worth noting that sometimes the blue highbeam indicator light on the dash comes on both in low and high mode when the lights aren't working. But sometimes only when on high beam (despite the lows not working). My understanding, which may be wrong, is that the indicator is simply a marker that the lights are energized and the low beams are NOT on)
I rarely drive at night so this was a low priority issue for me considerring how busy I was. Started looking at it today and found:
10A fuses for both headlights are fine, contacts clean and tight.
When I turn on the lowbeams I first hear a click at the relay above the kickpanel fusebox (sidewall to left of pedals). When I turn on the high beams I get a click at a relay, (Denso 90987-02006 ) that does not seem to be shown in the Haynes manual, in the relay/fuse box behind the battery.
When I turn them off I hear the clicks from the relays in reverse.
Noticed today that when I manually pull back to "flash" the high beams I get a squal from that relay.
Made the rounds but no one had that relay in stock- so I can't say yet whether that's the problem, or if it is something in front of, or behind, the relay. The relay looks good- which doesn't say a lot- and the contacts are tight and clean.
When I first started looking into this the nearest case I could find made me think it was the contacts associated with the light switch itself. (the turn signal lever/light switch). But....
Any thoughts before I go blindly replacing parts? Relays cheaper (and easier to replace) then the switch so that's where I'm inclined to start. Then if need be the switch itself.
But does anything I've presented here seem to rule out one or the other? Something else I should investigate first?
You have high resistance somewhere in the circuit, mostly likely the connector for the combination switch (light switch). I bet if you were to remove the connector to the switch, you will find a charred, partially melted connector pin.
When you turn the light switch on, you complete the connection to ground and that is what turns the lights on. If there is a point of high resistance in the ground circuit, the current will ground itself out through the high beam indicator.
The squall noise from the headlight relay is likely from the low voltage caused by the increased resistance. Much like a starter solenoid vibrates when you have a dead battery.
You can easily check this with a multimeter, or just pull the connector off the switch and check for burned connections.
If you have a multimeter, disconnect both connectors from BOTH headlights and check the following....
1) Find the red wire with a green stripe on the head light connector, this should have low resistance with ground when the headlights are in the low beam position. You should have less than about 1 ohm of resistance with ground. A typical charred contact will show about 5 ohms or more.
2) Find the Red wire with a yellow stripe on the head light connector. This should show low resistance with ground when the switch is in the high beam position, as described above.
Just remember to have both connectors disconnected from the headlights when you do this test to keep your meter from measuring the resistance in the filaments to ground. It will also keep your multimeter from measuring voltage when in ohms mode which can damage cheaper multimeters.
Last edited by rustypigeon; 06-19-2013 at 05:50 PM.
I have a very similar problem. Once in a while the high beam indicator comes on by itself and the lights turn off. I jiggle the switch and it goes back to normal. Also my high beams work only if I pull the switch, not if I push forward to leave them on. I have determined mine is a fault in the switch. Just haven't gotten around to replacing yet
My truck is 10 years older than yours but i would imagine not a whole lot has changed in this area. When i had a problem with the my headlights it was doing things very similar to yours. I checked everything and eventually pulled the combo switch out to find all the contacts where a little crusty. I cleaned them up with a very small file and now they work sweet like they should.
My truck is 10 years older than yours but i would imagine not a whole lot has changed in this area. When i had a problem with the my headlights it was doing things very similar to yours. I checked everything and eventually pulled the combo switch out to find all the contacts where a little crusty. I cleaned them up with a very small file and now they work sweet like they should.
Chad
I'll give that a shot. I already had it apart once to clean contacts because the blinkers were buzzing. Time to pull it apart again
I know this is a really old thread but I am having the same problem so I was wondering if anyone has found a solution.
I have replaced the combo switch, relay, and bulbs. I can't find any breaks in the wires but they are in a harness.
I borrowed a multimeter from a neighbor and checked the wires at the switch. They all show ground with little resistance (assuming I'm using the tool correctly). One wire , the red with white stripe, goes hard to the right on the meter (analog). So, to be clear, I can't get the meter to read 0 on the ohms scale, it stops at 3.5 when I've got the probes touching. Most of the wires that show anything are between 3.5 and 4 on the ohm meter, the red/white wire pegs to 0.
I started going through the tests and it seemed like have ground going through the fuses is not correct. It seemed like it should be 12 volts +. On further reading, I saw someone else who had 2 switches who was able to fix the problem by taking the switch apart and cleaning/regreasing it. So I tried this. I got high beams but no indicator light (I don't care, I have high beams!!!). So, I figured I just didn't clean or grease things well enough so I cleaned the plug in the truck. No more high beams. I took the switch apart again, tried to give it a more thorough cleaning and regreasing but I am back to square 1, no highs or lows, just manual flash.
I'm still thinking the problem lies in the switch so I'll order a new one.
I want to thank RADRunner for his excellent troubleshooting post.
The new switch arrived yesterday and I just now installed it. I still have the exact same situation and I'm completely baffled.
One thing I did notice while working through RADRunner's troubleshooting steps is that the fuses don't read hot, they read negative. Meaning, if I check them with a test light connected to ground the light does not light up, when I connect it to 12v + the test light lights up. Both the fuses are good, intact and show continuity.
Hi LoriB01,
Please use only a proper multi-meter and not a test light. I do not trust those.
Also please put us right at your truck. Save the schematic I posted and note what you read at each test point if different from what I describe and we'll go from there. Might not be able to respond quickly. Out of country for a little bit.
First off, I forgot in my first post to ask what vehicle you are working on.... so...
What vehicle are you working on?
We may need to find the correct wiring diagram / schematic for your vehicle to confirm that your headlight circuit is the same (or very similar) to the circuit that RAD4Runner has posted.
Test lights are an excellent diagnostic tool. They are good for testing circuit integrity, meaning the circuit's ability to carry current, which a multimeter may not catch.
Test lights are perfectly fine to use, just as long as you know what you are probing and what the results mean.
I personally like to work with both multimeters and test lights to get a more complete picture of how the circuit is performing.
Multimeters help us help you by giving us numbers to work with. Many of us are several thousand miles (kilometers) away and getting numerical results make it easier for us to see what is going on.
If I am reading your post correctly, when you have the clamp end of the test light connected to ground and you touch the tip of the test light to the fuse, the light does not light up.
When you have the clamp end of the test light connected to positive and touch the tip of the test light to the fuse, the light does light up.
Were the voltage measurements and test light tests done with the headlight switch in the "OFF" or "ON" position?
If your vehicle is wired in the same fashion as RAD4Runner's 1986 4Runner (and my 1987 Truck) AND you have the headlight switch in the "OFF" position (or first click stop, but not the second "headlight on" position), your test showed "normal" headlight "OFF" circuitry.
If above is true:
The reason you got this "backward" result is that the headlight fuses are powered by the headlight relay and should show no voltage until the headlights are turned on. When the headlights are turned off and the clamp end of the test light is connected to positive, touching the headlight fuses will cause the test light to light up because the test light is grounding through the fuses (which are disconnected from power by the headlight relay) and flows though the headlight circuit until it reaches the headlight ground. I confirmed this with a test light on my truck.
Now, if your tests were done with the headlight switch in the "on" position, then you have a positive voltage feed issue that we can help you with.
A digital multimeter would be easier for us to compare voltage values though, so if you can get your hands on one, that would be easiest for us to compare with RAD4Runners thread or a correct wiring diagram for your vehicle.
Sorry, my reply took so long, I don't have a garage so I have to work on it when time and weather permit. But I did the tests and notes today so here they are.
The vehicle is a 99 Tacoma SR5 without DRL. (Good question).
At the headlight:
Checking ground continuity with the headlight unplugged shows readings of about 3 on each wire
Checking 12volts DC with headlights on and plugged in and unplugged (the results were the same either way) RG wire = 17v RW = 17v RY = 17v. These numbers were the same for high beams and low beams.
At the relay:
I believe this is working correctly, I used a jumper wire instead of pulling out the fuse block and trying to get to the specific wires on the back but I found 2 pins were 12v always hot, 1 pin 12v switched and one 16v switched. I have a picture that I will post with the locations of the power.
At the fuse:
Headlights off = 4 ohms 0 volts Headlights on = 87 ohms (?!?!) 16v
The test light shows ground whether the switch is off or on.
At the switch:
WB wire (usually negative on a Toyota) shows 2 ohms
RG = 8 volts when low and high beams are on
RW = 2 volts with low and high beams are off
RY = 8 volts when low and high beams are on
Hi LoriB,
Let's re-group...
Please don't measure resistance when there is power to test points. Readings may no mean a thing and you could damage your meter.
We can troubleshoot by using only voltage checks.
Let's start by:
1) Telling us if you had red probe to test point and black probe to battery negative or bare, shiny metal of body ground when you did voltage check.
2) Indicate which relay pins (1,2,3,4 from schematic here) correspond to the relay socket pins in picture here.
3) Exactly which pin did you read 17 Volts? 1? 2? R-G? R-Y? When?
4) Refresh my memory... You still get flash, correct?
I reviewed your headlight circuit and it is exactly same as first-gens, except for SOME wire colors.
5) Please do voltage checks at points on schematic below EXACTLY AT ALL POINTS as I list them and re-post your annotated schematic.
Last edited by RAD4Runner; 11-08-2018 at 05:04 PM.
It seems like it's fixed (the headlight issue was intermittent for a while when it first broke so I'm paranoid)!
When I first bought the truck in 1999 I installed a Toyota alarm system. After about 10-11 years it stopped working so I pulled it out and reconnected the starter cut-off but left the rest of the wiring harness because it didn't seem to be hurting anything. I promptly forgot about it. When I took the lower half of the dash off to work on this problem I thought it might be a good idea to take that old harness out of the equation. I can't find anything wrong with the harness but removing it seems to have solved the issue (at least for now).
I cannot express my gratitude enough. I really appreciate all the diagrams and suggestions from rad4runner and all the other people here who don't know I was reading posts from years ago to try to solve this issue. Thank you all very much. I hope to be able to repay the favor.
I have a very similar problem. Once in a while the high beam indicator comes on by itself and the lights turn off. I jiggle the switch and it goes back to normal. Also my high beams work only if I pull the switch, not if I push forward to leave them on. I have determined mine is a fault in the switch. Just haven't gotten around to replacing yet
I have the exact same problem only I've chant l changed not only the headlight switch but relay as well. Still working ( or NOT working) the same. Im at a loss. Not sure what to do next. I've succumbed to manually using a lage fuse as a jumper to complete the circuit when driving at night and early morning. I REALLY would like to solve and fix this problem.
06-15-2013, 12:54 PM
