1993 Mustang Lx Turn Signal Issues

Nate.Alvarez72

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Nov 23, 2016
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Hey everyone,

Newbie to stangnet here. So I picked up a 93 Mustang LX 347 stroker a few days ago for a pretty decent price and it runs well right now. Anywho, as I was driving it home, I noticed that the blinkers weren't working (they were working the week that I went up to look at it initially) and the hazards work fine.
I watched several videos and read some forums about what it may be and it looks like my options are a bad flasher relay, bad turn signal switch, loose wiring in the back of the hazard switch (anything else?)
Quick question, if the turn signal switch was bad, would I still be able to select high beams? Because I can. So that's pending.
I checked for the loose wire in the back of the hazard selector and everything appears to be good.
Now onto the relay. I've looked for this thing in every place that I can think to look I.e. under the steering column, behind the radio, upper left in the glove box and I cannot find it anywhere. I'm thinking the problem could lie there. This question might be dumb but on the fuse box, the hazard relay is working fine, is there a separate flasher relay for the blinkers themselves? Just kind of beating myself up about not finding it and any advice or help works for me.
Looking through the wiring, it looks to me like someone may have tampered with or removed the harness at some point and kind of half assed put it back together. So you'll probably hear a lot from me over the next few months. Again, any advice helps!

Thanks,
Nate
 
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General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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Do they come on just not blink? Blinker fluid low.
Seriously, hazard flasher and turn flasher look the same but are in different places, I think it will be on the back side of the fuse box. I can look at my book in the morning to make sure unless someone post before I get up and iv a couple liters of caffeine.
 

Nate.Alvarez72

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Nov 23, 2016
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Haha blinker fluid. Nice! They don't come on or blink when I use the blinker, just the hazards. I appreciate it! I was looking on the back side to where I think a relay could go but it wouldn't fit.
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
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polk county florida
I looked in my book and if they do not come on at all and its not a fuse it will likely be the turn signal switch it self
The flasher is kinda hidden on a brace behind the fuse box may have to remove lower trim panel under stering wheel to get to it. Replace that if you have power to it when you activate signal if no power than it will be mulifuction switch. Key need to be in the on position
 

2011rustang5o

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Jan 5, 2011
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Multi function connection under the steering column. I had the same issue with my car. Forget the real name for it.
60a28652eccfbd4c4896533eba2aaf30.jpg


Sent from my iPhone using Tapatalk
 

General karthief

wonder how much it would cost to ship you a pair
Mod Dude
Aug 25, 2016
17,443
5,620
193
polk county florida
Multi function connection under the steering column. I had the same issue with my car. Forget the real name for it.
60a28652eccfbd4c4896533eba2aaf30.jpg


Sent from my iPhone using Tapatalk
I dunno, that looks like an ignition switch to me, but I was wrong before. I think the multifunction switch is on the steering column, left side with the fat stick poking out, not sure though.
 
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jrichker

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Multi function connection under the steering column. I had the same issue with my car. Forget the real name for it.
60a28652eccfbd4c4896533eba2aaf30.jpg

Sent from my iPhone using Tapatalk

That is most definitely an ignition switch... I have replaced 2 of them in the last year.

87-90 Mustang Turn signal troubleshooting


The ignition switch is also known for creating turn signal problems. Make sure the ignition switch and wiring are in good shape as a first item to check. This is especially true if you are having problems with things like the radio and heater/AC blower.

Ignition switch wiring


Some of the symptoms of ignition switch problems are things that don’t work or are intermittent like radio, turn signals, wipers or heater. The auto parts stores sell the switches for $13-$15.







While you are working on the switch, check the wiring and connector closely. A replacement connector with new wiring pigtails is available from most auto parts stores

AutoZone and Advanced Auto Parts have the same Part Number: 434 - may have to order, not always in stock

Advanced Auto Parts alternate part number: PT5534



If just the plastic shell is broken, a small jewelers screwdriver inserted from the front will release the contacts from the connector shell. Do this one wire at time and insert the wire and connector you removed into the same position on the replacement connector shell.

Saleen0679 was nice enough to dig this up for us awhile back: Replace a 1979-1993 Ignition Switch Assembly

Torx bit set from Advance Auto Parts



Autocraft torx bit set – have small hole in tip for tamper proof screws.
Part No. AC571/W1386 Cost approx. $12 +tax



87-90 Mustang Turn signal troubleshooting



Keep in mind that the flasher on the front of the fuse panel is for the hazard flasher. Locate the turn signal flasher, depending on the model year it may be behind the radio or on the backside of the fuse panel or behind the glove compartment.

Turn the ignition switch to Run; the engine does not need to be running for these tests. With the turn signal flasher removed, test the pink/orange wire for 12 volts.

Set the voltmeter to DC volts and select the scale that is closest to 12 volts. Clip one voltmeter probe on the bare metal part of the car body for a ground and put the other probe in the turn signal flasher socket contact that has the pink/orange wire. You should see about 12 volts.

No 12 volts present: replace the fuse and check for 12 volts again as described above. Do not turn the ignition switch off if you are testing for voltage.

Still no 12 volts, pull the fuse and test the #5 fuse socket contacts for 12 volts. One contact will have 12 volts. One probe is grounded, the other probe gets stuck in the fuse contacts. Test both contacts for 12 volts.

No 12 volts on either fuse contact, the ignition switch or ignition switch wiring is suspect. Move things around so that you can get to the backside of the ignition switch wiring connector with the ignition switch still connected to it. Make sure that you don't turn the ignition switch OFF while you are testing it. It still needs to be in the Run position. Look for 12 volts on the large gray/yellow wire. No 12 volts and you have a bad ignition switch or some bad wiring. Wiggle the large gray/yellow wire to see if it gets or loses voltage while you are checking it.

Diagrams courtesy of Tmoss & Stang&2birds

Fuse box layout


Ignition switch wiring


Once you have located the turn signal flasher, remove it from its socket and jumper the socket contacts together. Turn the ignition switch to Run and try both left and right turn signals. They should come on steady if you have good 12 volts to the pink/orange wire. If the lights turn on steady and bright, that means the flasher is suspect. If you find one more bulbs do not come on steady and bright, then you have either a bad bulb, bad ground at the bulb socket or a corroded or bad socket.

If you still have problems, then it is the multifunction switch, or its wiring; that is a case of last resort.

Multifunction turn signal switch:
Before you think about replacing the multifunction switch with one from the junkyard, here are some things to be aware of...

The problem is more common in GT models because they had fog lights on the same power wiring as the headlights. Ford undersized the wire and that caused problems.

A word of caution about multifunction switches is in order here. The multifunction switch (high/low beam, wiper, turn signals) are different for different years. 87-98 will work in any 87-89 car. The 90-93 switches only work in 90-93 cars. You can't put an early model switch in a late model car, nor can you put a late model switch in an early car.

Supposedly you can move the pins around to make the switches work in model years that are different from the car the switch came out of. I cannot verify that and haven’t tried it.

Other possible problem sources for the turn signal & headlight malfunction are the ignition switch, multifunction switch and the plastic shell that holds the turn signal wiring connector pins.

The following diagram is for 87-89 model cars.

Turn signal switch wiring:


The following diagram is for 90-93model cars.

Turn signal switch wiring:
 
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