No Headlights

Looking for some assistance....09 Tacoma has no headlights.

With Key On Switch On the only thing that works is marker lights and the green dashboard headlight on indicator. Highbeam indicator does not light up. If I pull the stem toward the driver and activate the momentary the high beams and dash indicator come on. Strangely the Fog Lights are also coming on. Usually they do not activate when high beams are on. I've never looked to see if they flash when using the momentary pull function.

With key on switch on, if I pull the Headlight Relay I have constant 12v power to a large terminal and a small terminal. The opposite small terminal has 8v power with switch on, 6v power with switch off. (seems unusual) The opposite large terminal has 0v at all times. If I jump the two large terminals I get all lights, high and low and fog and the high beam dash indicator works. But I cannot control them with the switch.

The Dim Relay appears to be working as designed when the headlight relay is jumped. I swapped the headlight relay with the A/C purple relay and experience no change, also tried another random relay I had laying around which made no difference.

Any thoughts?

 

Just a thought but seems you’ve got a better grip than I.
Any kind of lighting mods done on it?

 

Thanks @Jeffch - The truck does have a remote starter which was installed back in January.

 

This may help: The white wires ( Low Beams ) and the red wires with the black stripe ( Hi Beams ) goes to the headlight fuses in image # 2.

 

Thanks @Jimmyh still no luck on this one...

Does anyone know how to test the switch/stalk? I remain unsure of where the switch enters the whole relay loop out to the lights as well.

 

It would help to let us know what you have checked.
Do you own or know how to use a multimeter to check voltage and resistance?

If you do have a multimeter turn on the headlights and check the voltage at the headlight sockets while on low beam you want to check across the:
(Left Side Headlight) - Pink to white with black stripe (ground)
(Right Side Headlight) - Red with yellow stripe to white with black stripe (ground).

You should see 12 VDC with the lights on. If you have 12 VDC at the socket then the problem is the lamp or the socket isn't making good contact.

 

Thanks @Jimmyh - I have no power to the bulbs/sockets with switch on. No power to the 4 headlight fuses. There is power at Dim Relay and Power at Head relay. If you pull the stalk on the column the high beam light comes on with the bulbs as designed. If I pull the 4 pin Head relay I've got 0v on 3 pins with switch off. The small pin on the fender side heading toward the dim relay has 6v constant for some reason. With switch on I've got 12v at big pin on windshield side and 12v at small pin on engine side. 8v on that small pin on the fender side. If I put a jumper wire from big pin to big pin on the head relay (with it removed) I've got full function of the lights, high (with indicator) and low, but can't turn them off, switch seems to be bypassed.

 

If you look at the schematic I posted earlier. The Head Relay should have 12 VDC at Pin # 5 and # 2 ALL the time if the battery isn't dead.

The Body ECU Controls the ground for relay via the white wire terminal # 1 when you turn on the headlights via the stalk.

The relay should close when this ground happens and provides 12 VDC through the Red Wires to the DIM Relay Contacts and Coil.

The DIM Relay selects either High Beams or Low Beams as dictated by the stalk through the body ECU. If you have low beams selected by the dimmer voltage will go through terminals # 3 to # 4 and then on to the fuses and the bulb sockets.

 

@Jimmyh wow thanks for this explanation! I definitely have power at 2 and 5, I'll go check if that's constant or only appearing with key on/key off. Terminal 1 is where I am getting the random 6v/8v but never 12v and never anything but 6v or 8v with switch on or off. If I cross 5 to 3 I have full operation of headlights but can't turn anything off. So, I've got a new relay to test this morning, if that makes no change I am back to something on the wire upstream of 1 or the switch itself. Any thoughts on how to test the actual switch? Those tiny pins that connector on the column are tough to get at... I'm starting to get it!

Update - new relay makes no change though when plugging in for the first time the lights flashed, discovered that if you press one corner of the new relay hard enough it must connect two wires below as the lights have full functioning if you hold the pressure on the relay but no switch control as noted above when crossing 5 and 3. Power is constant at 2 and 5 regardless of key or switch position. With switch off 1 has 0v.

Replace the switch?

 

You should never see 12 volts at pin # 1 as it is the ground return leg for the relay coil through the body ECU.

It is good that when you jump terminals 5 to 3 the headlights work as normal as that removes everything downstream as working correctly. The problem seems to be in the control circuit and not the light circuit. So yes, the switch is a definite possibility.

I would first make sure that the terminals are not pressed out the bottom of the fuse panel and are making good contact as having to press on the relay seems odd like it isn't plugging in correctly. Or the white wire between the relay coil and the body ECU or one of its terminal ends.

This shows the stalk for the headlight controls if you want to try and read it with a meter.

 

@Jimmyh - thanks again for the amazing assistance! But still no luck....new switch arrived today without new results..plugged it in to test and there's no change, can't see any sort of ground on that clamp that holds it to the column so I gave it a shot and plugged it in without tearing the old one out.

I've managed to access the bottom of the fuse/relay panel in the engine bay and can't find anything out of the ordinary. I've also somehow lost the momentary flash ability. Crossing 3 and 5 on the head relay still makes it all sing without switch control. Current voltage to terminal 1 of the head relay is down to 2.5v from the 8v for some reason.

What is new and exciting is some sort of intermittent rapid clicking behind the under dash fuse panel. What's hiding behind those fuses? You hear a click like a relay when turning the switch on. Sometimes it goes crazy and has a super rapid clicking to it...having triple checked all wires and terminals under the hood I'm moving inside the cab.

Related or unrelated but the key fob won't work any longer either....

Update: replacing the new head relay with the old head relay gives me back the momentary (pull the stick) flash...

Anyone have any thoughts I'm at a complete loss!

 

Considering all that you have done I only have one other idea and that is the body ECU behind the interior fuse panel junction box. That is probably where you are hearing the clicking from.

If you remove that lower panel and get in behind the fuse panel you could check for a poor connection on a plug or something. The Body ECU is also behind there.

 

@Jimmyh thanks again sir, I am grateful for your thoughts! Will try peeling that Body ECU out and finding one to swap. Scanning the web leads me to believe this may be the issue as that module affects both the lights and the key fob. Greater concern is what fried that if this is the case....easy to point at the remote starter but that's been in there since January this year.

Is there a schematic for ground points that I could chase down and inspect?

 

This unfortunately, would be my guess of the cause of your issue. You have ruled out relays and switch. BTW, the troubleshooting process has been nicely done by you along with @Jimmyh.

 

Update: still no luck. There's no body ECU hiding behind that in-cab fuse panel, just a circuit board, looking for them on the web makes it look like a standard sealed up ECU.

The best reference I can get to one is from the diagram below but Toyota won't give me the option to buy it or the full part number just the first half of the number, 89221 , looks like it's on the left of the foot well and not behind that fuse block? https://parts.toyota.com/a/Toyota_2...1571/SWITCH--RELAY--COMPUTER/674470-8401.html

I went back to that head relay that I replaced. Baffled as to why when I push the one corner it hot wires the terminals and all the lights work. Also don't get the manual flash with the new one. So I popped the cap off the brand new relay and discovered that it's got a broken solder joint. When you push it back into place with some pressure that seems to cross the 3 and 5 terminals but doesn't give any switch control. The OEM relay when reinstalled gives me the flash back but sure doesn't hotwire the thing as the new one does...wtf?

The truck is winning.....if this was winter I'd be screwed...

 

I'm pretty sure that circuit board on the back of the interior fuse panel is the body control module.

 

This! I’ve had this piece go tits up on my truck. Replacement from a picknpull and no issues since!

 

Update: After several weeks of waiting I finally received a pre-enjoyed under dash fuse panel which includes the Body Control Module on it's backside. When installed, solved all issues immediately. Not even a need to re-program the key fob. Hesitant to reconnect the remote starter module, still no clue as to what caused the Body Control to fail!

For troubleshooters in the future: Jumping the Head relay terminals 3 and 5 in the engine compartment allowed me to confirm that everything downstream of the under hood relay was working. Plugging in (no physical ground so no need to install) a new column switch allowed me to eliminate the switch as the issue. Local NAPA took that $155 switch part back with a 10% restock fee. No Key Fob functions, Windows that worked regardless of key in or out, and a fried heater fuse under hood, all pointed the issue at that buried module under dash. Stress and annoyance expense can't be calculated...

Thanks to @Jimmyh for offering the wiring diagrams and advice!

 

Glad you got it, Good Job!

Thanks for the feedback.

 

Nice job guys...

I get dizzy when I try to read those electric schematics, looks like Chinese to me.