High Beam Problems

Hi all,

I've had a problem with my high beams that's gotten progressively worse over the last year. Here are the symptoms:

First, the high beams stopped working when switched on (with the lever clicked forward), but worked when held on manually (lever pulled back).

Over time, even pulling and holding the lever back manually only worked intermittently, with the lights turning off completely if I didn't pull the lever back with some force (scary).

Now, the brights don't work at all.


My assumption is that the problem is in the actual switch mechanism, probably some dirty or corroded contact. Today I took off my steering wheel to see if I could figure out where exactly the problem was. I have the Haynes manual for my year, but the diagram in the book doesn't reflect what my switch looks like. In the manual they describe different switch/lever modules for the headlight/blinker switch and the windshield wiper switch, while mine is a combo switch. The diagram for the control terminal also didn't match up with what was in my car.

Does anyone have a diagram of the headlight connector terminals so that I can check for continuity when the brights are switched on?

Without being able to do an electrical test, I decided to try and clean the high beam contact at the end of the lever. Apologies for not getting pics, but I've attached a (blurry) screencap from a youtube video indicating where I'm talking about. I removed the metal cover/contact shown, and found a ball bearing at the end of the lever. When the lever is pulled, it depresses a button below it. I'm not sure what happens when it's pushed away (high beams switched on). There was some grey/white grease in there, which I'm guessing is conductive? I cleaned the cover/contact, the ball bearing and the button under it with electrical parts cleaner and reassembled everything. Still no luck.


Any ideas? Did I clean the right contact? Would it make a difference to re-grease it? Did some solder joint break, or did a wire come loose from the harness somewhere? As you can tell, I really don't want to buy a new multi-switch assembly.

 

If you're willing to dig into it I think you can remove the switch from the combo switch. I did this on a Corolla with a similar switch. I remember having to remove some retainer that held the wires down maybe. Anyway, the part you are looking for is 3 leaf switches buried in there somewhere. When you pull or push the switch it makes different contacts between these 3 leaf switches. The button you mentioned is what pushes and pulls on the leafs. On mine I had to adjust the leaf switches by bending them slightly. I guess they bent out of shape over time. Then I had to check that I didn't bend them too far so it worked in all positions correctly.

And that ball bearing is a bitch to get back in especially if you haven't removed the assembly from the steering column.

 

Damn, wish I had read this just a bit earlier, just reassembled everything after cleaning that button and no luck. If I can muster the will to take it back apart, I'll try your suggestion. Quick question, is the button partially depressed when the brights are off? After studying the mechanism, I can't understand how it works unless that's the case. When you pull the lever towards you for momentary brights, the lever presses the button. But when you push the lever away from you to switch the brights on (semi)permanently, the lever is letting off the button. Does that mean that there's a third position for the button, partially depressed when the brights are off?

Another thing that's baffling. I looked at the back of the button housing, there seem to be three wires coming out, call them A (red w/yellow) ,B (red w/white) and C (white). I did a continuity test with my multimeter and found that with the button off, A & C were connected and with it depressed B & C were connected. Does this mean the switch is working fine and my problem is elsewhere?

 

I can't remember. I'll see if I have any pictures from a few years ago. There might be a spring involved with that button. I think the button has 3 positions and the ball bearing might determine those positions. The ball bearing can rest in 2 spots and the pulled back position springs back when you let go.

I'm not sure about the wires and continuity. The repair manual should give the specs. I'll take a look if I have time.

 

I couldn't find any pictures of my disassembled switch.

The repair manual (1996) says:
low beam position, continuity A3-A9
high beam position, continuity A9-A12
flash, continuity A9-A12-A14

These pinouts in the connector may be the wires you are referring to. I guess A9 may be the wire to ground. In the flash position A14 turns the headlight relay on, like when you flash without the headlight switch on. I don't have the complete wiring diagram, but I think someone posted it in a recent thread.

 

Here is the recently posted headlight wiring diagram. Not sure what year it is from, but should be similar.

https://www.tacomaworld.com/threads/high-beams-work-low-beams-dont.486224/#post-14912740

 

The headlights work as a ground switched system. Both the high and low beam wires are 12v+ whenever the headlight circuit is on. The switch connects the ground to each of the circuits. When you pull back on the lever is leaves the low beam circuit connected to ground and adds the high beam. When you push the lever forward it removes the ground from the low beam and connects the high beam.