Electrical Issue With Turn/hazard light signals

[MisterMo21]

Hey, guys so I need help figuring out an electrical situation. For some odd reason, my turn signal lights do not flash when turning them on BUT when I hit the hazard lights a couple of times, the turn signals turn back on and work (the hell). Anyone know what this problem could be? I would really appreciate any ideas on what could be causing this! Thank you!

 

[MyFirstRunner]

Hey, guys so I need help figuring out an electrical situation. For some odd reason, my turn signal lights do not flash when turning them on BUT when I hit the hazard lights a couple of times, the turn signals turn back on and work (the hell). Anyone know what this problem could be? I would really appreciate any ideas on what could be causing this! Thank you!

I had some similar goofy issues including turn signals, wiper blades, etc. doing odd things and not working as they should. I swapped out my body ECU and that solved it.

Could also be in the wiring harness or a ground but in my case it was the circuit board.

 

[MisterMo21]

I had some similar goofy issues including turn signals, wiper blades, etc. doing odd things and not working as they should. I swapped out my body ECU and that solved it.

Could also be in the wiring harness or a ground but in my case it was the circuit board.

Is it a simple fix?


Sent from my iPhone using Tapatalk

 

[TheDurk]

Well, Body ECU would not be my first suspect for this exact symptom set. The circuit does transit the B-ECU but they are just straight traces--probably fixable if they ARE the problem, which I doubt. The exception is the Flash relay, but that can be swapped separate of the B-ECU. Thing is, the turn circuit uses the exact same cross-connections on the B-ECU, so if it was bad for one, it would be bad for the other. A B-ECU is wildly expensive new, so you are talking junkyard. It is not that hard a swap, but it's a lot of plugs and wires. I'd go to some effort to rule everything else out, before I went that way.

My first suspect would be the Hazard Switch, as in it is not returning control of the circuit to the turn circuit when cycled to off. Play with it enough, and it restores the Turn circuit. It's really the only thing that is different between the two circuits.

Key question is does the green-red wire between the hazard switch and the flash relay have 12V+ when Hazard is OFF and key is ON. If it does not, Hazard Switch is your culprit. If it does, then I would try a new flash relay before I swapped the whole B-ECU.

Actually, I'd do a whole lot of other things before I swapped the B-ECU.

OP does not give year (Grrrr....) so here is 2002 EWD. I think other years are the same.



http://tacoma.site40.net/4Runner_96-02_Repair&Wiring/techinfo.toyota.com/ileaf/ewdtmc2/ewdtmpdf/ewdsourc/2002/024runne/systemci/022tshwl.pdf

 

[MisterMo21]

Well, Body ECU would not be my first suspect for this exact symptom set. The circuit does transit the B-ECU but they are just straight traces--probably fixable if they ARE the problem, which I doubt. The exception is the Flash relay, but that can be swapped separate of the B-ECU. Thing is, the turn circuit uses the exact same cross-connections on the B-ECU, so if it was bad for one, it would be bad for the other. A B-ECU is wildly expensive new, so you are talking junkyard. It is not that hard a swap, but it's a lot of plugs and wires. I'd go to some effort to rule everything else out, before I went that way.

My first suspect would be the Hazard Switch, as in it is not returning control of the circuit to the turn circuit when cycled to off. Play with it enough, and it restores the Turn circuit. It's really the only thing that is different between the two circuits.

Key question is does the green-red wire between the hazard switch and the flash relay have 12V+ when Hazard is OFF and key is ON. If it does not, Hazard Switch is your culprit. If it does, then I would try a new flash relay before I swapped the whole B-ECU.

Actually, I'd do a whole lot of other things before I swapped the B-ECU.

OP does not give year (Grrrr....) so here is 2002 EWD. I think other years are the same.



http://tacoma.site40.net/4Runner_96-02_Repair&Wiring/techinfo.toyota.com/ileaf/ewdtmc2/ewdtmpdf/ewdsourc/2002/024runne/systemci/022tshwl.pdf

I was thinking it was the hazard switch due to the part of when I bought the vehicle the previous owner put on some kind of fake carbon fiber trim by the hazards, so I was thinking it could be that because it blocks the hazards from coming all the way out. But when I push the hazard button out it works but all of a sudden sometimes when I turn my car on and try turning the signals won't work until I start pressing the hazards again.

And to see the green wire, do I have to take off the whole trim to see it? another thing is that my ECT button doesn't even engage so could it be some crazy electrical problem? and sorry but what is a B-EC? (sorry I'm new to this forum stuff and the whole reason i got this vehicle is to learn how to fix things)

 

[TheDurk]

I was thinking it was the hazard switch due to the part of when I bought the vehicle the previous owner put on some kind of fake carbon fiber trim by the hazards, so I was thinking it could be that because it blocks the hazards from coming all the way out. But when I push the hazard button out it works but all of a sudden sometimes when I turn my car on and try turning the signals won't work until I start pressing the hazards again.

And to see the green wire, do I have to take off the whole trim to see it? another thing is that my ECT button doesn't even engage so could it be some crazy electrical problem? and sorry but what is a B-EC? (sorry I'm new to this forum stuff and the whole reason i got this vehicle is to learn how to fix things)

Hell, yeah! If the Hazard switch can't travel all the way to its rest OFF position, then that could definitely keep it from switching the turns back on. It is not really a Hazards ON-OFF switch, it's a HAZARD ON-TURNS ON switch.

B-ECU is Body ECU. ECU is Toyota Speak for little computer (formally Electronic Control Unit).

Yes, you would have to pull the center fascia to get to the back of the Hazard Switch and the green-red wire. But don't sweat the wire, just pull the fascia, unplug the Haz switch, pull it loose, and clean all that vinyl crap off until it works normally. Will bet that's all you need.

ECT is a separate problem, unless there is vinyl crap in there, too. Don't overthink simple stuff.

 

[MisterMo21]

Alright man I'll try that, thanks for all the information helps me a lot! I'll keep you posted


Sent from my iPhone using Tapatalk

 

[MyFirstRunner]

Is it a simple fix?


Sent from my iPhone using Tapatalk

I agree with everyone else that you should check the obvious stuff first. If you run out of options, yes, swapping the B-ECU is very easy if you can find one from a junk-yard or from someone parting out a junker. OEM replacements are pretty expensive.

 

[sthomps30]

Some of the same electrical issues you mention, mind if I piggyback?

Been lurking a long time, just started posting, apparently not enough to start a new thread...

Have an odd electrical issue - part of which OP mentioned I'm trying to diagnose

Did an LED light swap in the dash - backlight only as I've heard swapping the 74s can cause issues. D & L were also out so I replaced with one bulbs from junkyard.

Now I have 2 sets of issues:

Dimmer off - ECT flashes when turn signals are used (as does whatever gear I'm in)

Dimmer on - turn signal indicates wrong direction on cluster, ECT & GEAR flashes, R flashes & engine revs oddly?

Hoping it's a bad ground somewhere but new to molding & wrenching & wondering if anyone might know where to start poking around to resolve.

Thanks!