88 Mustang Turn Signals Don't Work.

Lizard500

New Member
Mar 27, 2016
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Put a new heater core in my stang and now my turn signals don't work. I have an 88 LX stang 2.3 (squirrel motor).
*I have replaced both flasher relays (one behind the fuse panel and the other behind the radio)
*replaced the ignition switch under steering column as it had separated (this was replaced before the heater core)
*replaced the key cylinder (before heater core replacement)
*I've replaced the hazard switch in the dash and have replaced the wire connector into the back of the hazard switch which had broken when I removed the hazard switch to take the dash out to install the heater core (fun finding that little hazard switch wire connector and all sites have the wrong one listed. Finally found it on ebay under 92 ranger window switch connector).
*I have read all of the "turn signals don't work" threads on this site and I have done all of the recommendations.
*Turn signals work when I have the turn signal arm on the steering column either down or up for left or right turn signal when I hold the appropriate signal wire together with the power wire.(Hazard switch is out of the dash.)
*My hazards work no matter what when I have the hazard switch plugged in.
*When I have either turn signal wire held together with the power wire when making a turn, if I don't let go of the connected wires when the turn signal arm on the column pops to the off position, the hazards start blinking.
*I currently have the hazard switch out and rigged so I can use my signals without going through the hazard switch.
Can I say "HELP ME" now?
 
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Click on the drawing to enlarge

turn-signal-wiring-87-90-mustang-jpg.545554


All tests done with the ignition switch in the Run position

12 volts at pink/orange wire; yes or no?

12 volts at lt blue wire; yes or no? Try this with the turn signal set for either right turn or left turn and then for no turn..

12 volts at orange/yellow wire; yes or no?

12 volts at the lt green/white wire. Try this with the turn signal set for left turn. Good 12 volts? yes or no.

12 volts at the white/blue wire. Try this with the turn signal set for right turn. Good 12 volts? yes or no.
 
Orange yellow wire pulled out of the connector at my plug on my column after my dash swap. Hazards worked no issues. Just no turn signal.
 
Does anyone have an 88 mustang in this forum who would be willing to take photos of the wiring into the multi function turn signal switch plugs for me? Mine has different wire colors than all the ones that i have found online. Some of the wires have come out and I need to know where the heck they go. I need to know where the white and light blue wire goes.
 
Does anyone have an 88 mustang in this forum who would be willing to take photos of the wiring into the multi function turn signal switch plugs for me? Mine has different wire colors than all the ones that i have found online. Some of the wires have come out and I need to know where the heck they go. I need to know where the white and light blue wire goes.


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:
attachment.php?attachmentid=35089&d=1117654157%20.gif
The following diagram is for 90-93model cars.

Turn signal switch wiring:
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