I just bought a 1998 4Runner SR5. when I test drove it, only the low beam worked, switching to highs resulted in darkness, however holding the "flash" function back made both highs and lows light up. then the other day the headlights stopped working so i tried the high beams and they worked now. so for now I am driving with high beams. The fuses look good, as do the bulbs, I can hear the relay clicking when I turn the lights on. I replaced the combo switch because I figured that was the problem but there was no change. Any thoughts!?!?
thanks

 

I just bought a 1998 4Runner SR5. when I test drove it, only the low beam worked, switching to highs resulted in darkness, however holding the "flash" function back made both highs and lows light up. then the other day the headlights stopped working so i tried the high beams and they worked now. so for now I am driving with high beams. The fuses look good, as do the bulbs, I can hear the relay clicking when I turn the lights on. I replaced the combo switch because I figured that was the problem but there was no change. Any thoughts!?!?
thanks

 

Check the head light relay.

 

Before you get in to all that wiring I would try new headlights. Just keep the receipt if it doesnt fix it return them. I have had my low beams go out twice and new headlights fixed it.

 

ill give it a shot, thanks.

 

how? it clicks. how do i test it to see if its working the right way

 

it is your combination switch...by the sounds of it it may be able to be fixed by a good clean if not just replace it.

 

jumper the coil side of the relay to a power source and check for resistance across the switch is one way.
using the same multi-meter you can also check the power and grounds on the wires.

I've had a few times where you'd hear the click but nothing happened with relays and VSVs. Check to make sure what's supposed to happen is happening.

 

Just because you hear the coil pull in the relay doesn`t mean the contacts are touching or not as the case might be.

It could also just be a bad connection that needs cleaned

your multimeter is your friend more than one is a great idea

 

i did. i cleaned and then replaced the combo switch and the problem stayed the same

 

Combo switch was replaced? The headlights are a pretty simple circuit really, your just going to have to troubleshoot it with a multimeter and find the problem then.

The headlight relay (engine fuse box) receives constant 12V. The output goes straight to the bulbs. It is switched via the combo switch, or more so the light dimmer switch in the combo. When your headlights are in the 'on' position or your high beam is pulled back a ground is sent to the relay. At the same time a ground is sent to one set of bulbs to turn the things on.

Areas to check -

Relay has power in
Relay has power out when headlights 'on'
Headlights have power when headlights are 'on'
Headlights have ground when headlights are 'on'

Toyota troubleshooting lists these possibilities -

Fusible link blown
Headlight control relay faulty
Light control/dimmer switch faulty
Wiring and ground faulty

It is still most likely the combo switch, I replaced mine not to long ago. When the headlights were turned to the 'on' position they wouldn't switch but would if you pulled the switch back for high beam flash.

 

So i replaced the headlight fuses and the bulbs today in addition to the new relay and combo switch I did last week...the result was light, high beams and low beams!!!
Just goes to show you really should check the little stuff 1st. Im still confused as to what happened since the truck originally had only low beams when I test drove it, then only high beams when I picked it up. The problem seems to be solved now though!!
I put Sylvania Xtravision so we will see how they hold up.
thanks guys