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Flash/turn signal fuse burns out every time


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completelyhis
User

Apr 7, 2007, 10:40 PM

Post #1 of 16 (5346 views)
Flash/turn signal fuse burns out every time Sign In

I've got a 2002 Toyota Echo we took to Mexico with our church group. while in mexico, someone said they thought they heard something like running over something and having it drag, or something like that, while they were driving. BTW - it was loaded w/ 5 adults and a trunk full of stuff, quite possible the back dragged as they accellerated out of hte intersection) they then noticed no turn signals. It was the 10a fuse. I replaced it, and after the signals worked about 5 seconds, the fuse burned again. replaced it, burned again. I inspected the wiring harness around the front/back light areas, and it seems fine.

any ideas what would be causing this? the running and break lights still work. Could it be a bad ground? hot wire being grounded? hot wire arcing on hot wire?


DanD
Veteran / Moderator
DanD profile image

Apr 8, 2007, 6:57 AM

Post #2 of 16 (5339 views)
Re: Flash/turn signal fuse burns out every time Sign In

With the excessive weight and whatever happened during this dragging has likely pinched a wire somewhere in the circuit; due to the flexing of the body.
Yes to all of your could be’s; which one will take some searching?
Sorry I don’t have anything specific to tell you, good luck and keep us updated in your search.
Dan.

Canadian "EH"






completelyhis
User

Apr 8, 2007, 9:16 AM

Post #3 of 16 (5337 views)
Re: Flash/turn signal fuse burns out every time Sign In

Is there any sort of testing I can do, to look for the grounded/pinched wire...to see if it is a certain signal (front left, front right, etc)? Maybe w/ an ohm meter, or even with a few fuses, and taking the lights out, new fuse, turn signals on...when it doesn't blow...I know that's the light that's giving me greif...anything like that work?


DanD
Veteran / Moderator
DanD profile image

Apr 8, 2007, 12:09 PM

Post #4 of 16 (5335 views)
Re: Flash/turn signal fuse burns out every time Sign In

There’s nothing specific that I can tell you as too where or what to look for; your idea of removing/disconnecting something in the turn signal circuit and a new fuse is definitely a place to start.
Good luck and let us know what you’ve tried?
Dan.

Canadian "EH"






completelyhis
User

Apr 10, 2007, 9:41 PM

Post #5 of 16 (5327 views)
Re: Flash/turn signal fuse burns out every time Sign In

I put in a new fuse...turned signals to the left...didn't burn out. turn them to the right, immediately burned out. removed rear right bulb, didn't burn out, front flashed. replaced right rear, removed right front, the fuse didn't burn out, right rear worked.

so, it seems that whatever the problem is, it is on the right side, and is not "strong" enough to cause the fuse to burn when only one light flashes.

does this help focus my search? ie, wiring for right side of chassis, a specific issue that would exhibit these characteristics (arching wire, loose wire, grounding wire)?

thanks,
Ian


DanD
Veteran / Moderator
DanD profile image

Apr 11, 2007, 5:44 AM

Post #6 of 16 (5324 views)
Re: Flash/turn signal fuse burns out every time Sign In

What happens when you turn the hazard (4 way) lights on, do all four corners flash?
If the hazards are working properly that kind of tells me that the wiring from the flasher unit too all four corners is likely ok?
When the turn signal fuse blows, what else stops working?
According to the diagram that I have, the turn signal fuse also protects the circuits for the rear window defogger switch, heater relay, door lock control relay, shift lock control relay and a couple of others depending on what accessories the Echo has.
I just want to make sure that I’m looking at the proper wiring diagram for this car.
The diagram that I have shows one 10-amp fuse for the turn signal (left & right) possibly labeled “gauge” and a different dedicated 10-amp for the hazards.
What I’m beginning to think, is that the turn signal/hazard relay may possibly be at fault?
Even though left turn, right turn and hazards are all using the same flasher relay; the inputs to the relay are different; internally the flasher maybe shorting, causing excessive current flow, blowing the fuse when all light bulbs are in place?
Again this is if the diagram that I have is accurate; it wouldn’t be the first time that after market suppliers printed the wrong or inaccurate information. LOL
Dan.

Canadian "EH"






completelyhis
User

Apr 11, 2007, 8:17 AM

Post #7 of 16 (5322 views)
Re: Flash/turn signal fuse burns out every time Sign In

The labels for the fuse panel show that the one 10amp fuse I'm replacing is "HAZ." There is one 10 amp labeled guage, but it isn't blowing. I did notice that when the turn signal fuse is blown, the hazards don't work. I'm not sure about heater relay and rear defrost. I don't have power locks. I'll pick up a flasher today and check it...cheaper diagnostics than taking it to an auto electrician!

Thanks,
Ian


completelyhis
User

Apr 11, 2007, 10:03 AM

Post #8 of 16 (5318 views)
Re: Flash/turn signal fuse burns out every time Sign In

i was just talking this over with a buddy...got to thinking, if it is a flasher unit, wouldn't it be blowing the fuse both right and left, not just right?


DanD
Veteran / Moderator
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Apr 11, 2007, 2:59 PM

Post #9 of 16 (5317 views)
Re: Flash/turn signal fuse burns out every time Sign In

Now that you have told me that it’s the hazard fuse that blows then not likely the flasher relay, unless the hazards will work after the fuse is replace and the fuse only blows when right turn is used.
Like I asked do the hazards work (after fuse is replaced)?
Dan.

Canadian "EH"






completelyhis
User

Apr 11, 2007, 5:47 PM

Post #10 of 16 (5315 views)
Re: Flash/turn signal fuse burns out every time Sign In

yeah, the hazards work with a new fuse. actually, i was looking at it with a friend today, we did nothing I haven't already done...pulled a bulb out a looked at it, tugged on a few wires and looked at them, grunted, pointed, the usual. the difference, this time the right side works...the problem seems to have dissapeared. Weird, eh?


DanD
Veteran / Moderator
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Apr 11, 2007, 6:35 PM

Post #11 of 16 (5313 views)
Re: Flash/turn signal fuse burns out every time Sign In

Weird maybe but that’s the joy of electrical and electronics and that’s why I suspect the relay. Yes they; left, right and hazards all use the same relay but the relay gets/uses different signals for left, right and hazards. (Internal short)
Now that the issue seems to have gone away there’s no way of proving who is doing what to whom, or who isn’t. My whole point was that if all lights worked in hazards but blew the fuse for right turn then the circuit after the flasher relay must be ok. The same wiring, bulbs are used for both after the relay.
This is just my theory and without doing actual tests; I’m just guessing.
Dan.

Canadian "EH"






PTEC
User

Apr 17, 2007, 5:59 AM

Post #12 of 16 (5292 views)
Re: Flash/turn signal fuse burns out every time Sign In

my bet is on the short to ground. you know the bulb that keeps popping the fuse? check terminal for short, then from that bulb terminal, trace line back im pretty sure you'll find what you're looking for.


DanD
Veteran / Moderator
DanD profile image

Apr 18, 2007, 3:38 AM

Post #13 of 16 (5283 views)
Re: Flash/turn signal fuse burns out every time Sign In

PTEC of course it’s some kind of short but not necessarily to ground. Did you read where completelyhis wrote.

Quote
I put in a new fuse...turned signals to the left...didn't burn out. turn them to the right, immediately burned out. removed rear right bulb, didn't burn out, front flashed. replaced right rear, removed right front, the fuse didn't burn out, right rear worked.

That tells me that there isn’t a hard short to ground in the harness or the bulbs themselves but excessive current flow when the right signal is turned on with all the bulbs in place.
Plus they wrote that

Quote
yeah, the hazards work with a new fuse

That tells me from the switch to the four corners, the wiring and bulbs must be ok or the fuse would blow anytime the right side was energized. Hazards use the same circuit as the turns do after the switch.
Looking at the wiring diagram for this car the only other place where the three different circuits (left, right turn and hazards) meet is at the combination flasher. The diagram shows power input from the fuse panel and then three outputs to the switch, left, right and hazards.
That’s why I keep leaning towards the flasher unit, when right turn is on there maybe an internal flasher short, back feeding another circuit, increasing current flow blowing the fuse?
All of this is pointless now that the system is magically working now but that in itself makes me even more suspicious of the electronic flasher. Hard shorts to grounds usually don’t just go away but electronics’ love playing the intermittent game.
Dan.

Canadian "EH"






MartyLefty
New User

May 15, 2007, 10:36 AM

Post #14 of 16 (5206 views)
Re: Flash/turn signal fuse burns out every time Sign In

Since the problem of blown fuses seems to have gone away, is this the last we shall hear of it in this thread (thread? or whatever it's called)? I just found this forum and became interested in why only the right-side turn signals caused the problem.

I've been trying to visualize wiring/switches, contacts, etc. that would result in the energized circuit for the right-side flasher bulbs apparently causing a fuse to blow. Actually, not that as much as the fact that an activated right-front circuit not blowing the fuse as long as the right-rear bulb had been removed. (I think I understood that description correctly). Morover, the same thing would happen with right-front bulb removed and right rear bulb in place.

So when only one of the right-side bulbs is removed and the right blinker switch is turned on, the fuse does not blow. Correct?

I'm trying to envision the inside of the flasher unit. Exactly what are the electrical pathways and connections? Is there a diagram of the inner workings of the flasher unit? I'm fairly ignorant in the area of auto electrical systems, but I want to learn.

Anyway, with the above scenario, in order for a fuse to blow (within the constraints of all the symptoms described), too much current has to be going from somewhere in the flasher unit to the 2 right-side bulbs. I think. So why is there not enough current to blow the fuse when circuit to either front or rear is broken by bulb removal?

Would looking at a deatailed diagram of the flasher unit be useful? Does anyone have one? I'd sure like to see it. Thanks.


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

May 15, 2007, 12:31 PM

Post #15 of 16 (5203 views)
Re: Flash/turn signal fuse burns out every time Sign In

Hi and welcome to the forum. Wish you had posted just your own as now it's a long thread and it's easy to do but I'm confusedCrazy If you don't get your answer just post new and name the type of car and year.

You really don't need to know how the inside of a flasher is wired or works because you can't fix them anyway. They are empowered by your key position and direct current from your turn signal request to the bulbs. Ok I'll explain ---- a bi-metal strip with contacts heats up and makes it connect for lights, gets warm and disconnects so that the lights blink.

If there's too little draw on it they may light but not blink and too much they would blink fast or blow a fuse if too much. Bulbs are not all the same even if they fit. The "wattage" could be a lot different and cause a fuse to blow or the socket could be corroded or screwed up in some way to short it out, that and the wiring usually near it can be disturbed like in a trunk but could be anywhere.

Flashers are not very expensive and it could be the problem. Easy and cheap to try a new one but I would verify that the correct bulbs are in the socket. If you do try a new flasher and it doesn't solve the problem we'll have to go find out why but most are what I just mentioned. I don't like just tossing parts but the flasher could be cheaper than the time spent trying to diagnose just it.

Again, start a new post of your own and you'll get better exposure. I was going to try to move just your post but that could have been confusing this even more so here we are at the tail end of a "thread". Folks are here and watching but it's more apt to get looked over if not on its own,

T



DanD
Veteran / Moderator
DanD profile image

May 16, 2007, 5:31 AM

Post #16 of 16 (5205 views)
Re: Flash/turn signal fuse burns out every time Sign In

Because parts of the circuit work without blowing the fuse I would be looking at what is common to all parts of the circuit and in this case the flasher relay is.
This relay is like everything else these days, it’s electronic and the wiring diagram only shows it as a box with its inputs and outputs. We as technicians would test it by knowing what the inputs and outputs should be; if they are, change the relay, if they’re not, find the external problem.
This relay has 5 inputs, keyed power, battery power, left turn from switch, right turn from switch and hazard switch. It also has 3 outputs left side to lights, right side to lights and ground.
Knowing that the hazard fuse holds with the hazard switch on and all lights flash; that tells us that all external circuitry to and from the flasher relay is ok; same for left turn. But once right turn is turned on with all bulbs in place the hazard fuse blows.
Knowing the above the only place that the hazard fuse could come in contact with the right turn signal input is the flasher relay.
Why it suddenly started to work properly, who knows; it’s the joy of electronics.

Dan.

Canadian "EH"










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