2001 Tacoma Bright Lights don't work

Current status:

• Daytime running lights and low beams work high beams don't
• checked all fuses both visually and with ohm meter, all good
• replaced head light relay
• tested lamps, all good
• Replaced combination switch on steering colmn
• no luck
• no high beam indicator light

On the wiring diagram it shows the high beam indicator goes through the daytime running light relay (main). Is it possible that the daytime running lights relay is bad even if everything else works connected to that relay?

Any other suggestions?

 

You're in the 2nd gen forum. Most of the people here don't know didley about 1st gens. I do vaguely remember there being something really odd about how the headlights are wired on those trucks. Post in the 1st gen forum and I'm sure they'll help you get it sorted out.

 

@NunyaBizness can we get a topic bumparoo?

 

Huh

 

Last I checked 2001 was squarely in the first gen category

 

I did a quick search on the 1st gen forum and found the schematic. I was right. It's pretty screwy. The headlight switch supplies power to the headlight common terminal. (The terminal that is connected to ground on "normal" vehicles) Then the dimmer switch grounds the high beam or low beam side of the bulb. Now here's the REALLY screwy part. The high beam indicator is wired to the low beam circuit. How can that work? Well, when the high beams are on, there is still voltage is going through the low beam filaments (even though they're not illuminating) and supplying power to the high beam indicator. When the low beams are turned on, that side of the bulbs are connected to ground so the high beam indicator doesn't light. Somebody was really stoned when they came up with that circuit.

https://www.tacomaworld.com/attachments/headlight-pdf.3057004/

 

Huh... Weird...

 

The OP copied his post to the 1st gen forum. I copied my reply over there as well.

 

Now we're on the right track.

https://www.youtube.com/watch?v=_x2m6i4KFqg

 

@RysiuM seems to have a good solid grasp of how the Canadian 1st gen DRL system works. Maybe he can "shed some light" on the situation.

 

As much as I love 1st gen for simplicity I hate to admit that in 2nd gen Toyota fixed at least two screw-ups they put in the first gen: LBJ and Headlight circuit.

So there was no need to replace Head Relay - it is just delivering power to headlights - if any of the headlight function work, then that relay is OK. So all works except High Beam and High Beam indicator.

Please define what "low beams work high beams don't" mean. For example what happens when you turn on the flash. Will it turn on low beam or just nothing? Whet happens when you switch from low to high beam: the lights are still on low or lamp goes dark?

If it always stay on low beam it could be as simple as the "Dimmer relay" bad. But if Dimmer Relay does not get the signal (ground to coil contact from Violet/Yellow wire) than it could be either something wrong with the electronic circuit in Daytime Running Light Relay (Main) or maybe no connection between the combination switch and Daytime Running Light Relay (Main) - the Violet wire between contact 7 of combination switch and contact 16 in Daytime Running Light Relay (Main). That is quite possible and simple and would explain why the High Beam indicator does not light up.




If lamp goes dark when switching from low to high then most likely it is a "Dimmer relay" (highlighted below) switching but not delivering power (bad contact between relay and the base or inside the relay or maybe there is no continuity between the relay and Head fuses (inside the fuse box shown on the diagram below as a White-Red wire between relay and fuses). If this is the case you high beam indicator might be separate issue (including burned or not contacting indicator bulb).

 

RysiuM, thank you for the response.
With the engine running, the DRLs work. when I turn on the flash (pull the switch toward me) the low beams come on. With the head lights turned on (low beam) and I turn on the flash, nothing changes.

 

You're the freaking man Rysiu

 

All depends in Hi Beam indicator lights up or not. If it does not then probably "no connection between the combination switch and Daytime Running Light Relay (Main) - the Violet wire between contact 7 of combination switch and contact 16 in Daytime Running Light Relay (Main)." If it does light up then probably the "Dimmer relay" bad.

 

My 2003 DC TRD with DRL module was doing exactly this tonight. Confused me for a bit.

The low beams seemed to be working fine.
The pull-to-flash high beams worked fine and the blue indicator light illuminated when held on.
The push-to-high/main beam did nothing. The low/dipped beams stayed lit and no blue indicator light.

The fix -- turn the headlights all the way on! I had the switch in the DRL position (which I don't normally use). All good now. And the low beams are a little brighter, too.