on again, off again turn signals

Arthur McDonald · **Joined:** Fri Aug 29, 2003 1:54 am **Posts:** 2052

The turn signals on my old (1990) Mustang died the other day while I was running errands. Got home in rush hour traffic with hand signals and the fewest left turns possible. The 4-way flashers still worked, so I fear this not just a matter of replacing the solenoid and might involve replacing the multi-function stalk. I had to move the car today, and tried the signals and they worked. I drove it a short distance, turned it off, then restarted, and they did not work. (Again, the 4-way flashers worked) Restarted the car and the turn signals worked again. Anybody had a problem like this?

Patrice Bousquet · **Posted:** Fri Aug 24, 2018 7:12 am

check grounding of the bulb and the light assembly. bad ground can do crazy stuff.

Keith Roberts · **Joined:** Wed Sep 17, 2014 12:14 pm **Posts:** 31

I found wire diagrams for an 86 and 94-95 Mustang.

The 86 used separate mechanical flasher devices for turn signals and hazard flashers.
The 94-95 used a electronic flasher that looks like it handles both functions.
The mechanical devices might be swappable to see if the problem moves.
The electronic flasher, the best you can hope for is to reseat the connector and see if it starts to works. Otherwise it will need to be replaced.

http://www.veryuseful.com/mustang/tech/ ... iagram.gif
http://www.veryuseful.com/mustang/tech/ ... ghting.gif

I checked autozone for mustang flashers 91 & 99s, but they showed the same groups of flashers. It'll give you an idea of what the flasher devices look like, and then it's a matter of digging around under the hood or dashboard to find it. The good news could be that they're less than $20.

keith

Vincent Keene · **Posted:** Fri Aug 24, 2018 1:18 pm

Art, at your age what are doing using turn signals anyway? :mrgreen:

Keith Roberts · **Joined:** Wed Sep 17, 2014 12:14 pm **Posts:** 31

The easiest way to find the flasher is to turn on the hazards, and follow the sound.

Keith Roberts wrote:

I found wire diagrams for an 86 and 94-95 Mustang.

The 86 used separate mechanical flasher devices for turn signals and hazard flashers.
The 94-95 used a electronic flasher that looks like it handles both functions.
The mechanical devices might be swappable to see if the problem moves.
The electronic flasher, the best you can hope for is to reseat the connector and see if it starts to works. Otherwise it will need to be replaced.

http://www.veryuseful.com/mustang/tech/ ... iagram.gif
http://www.veryuseful.com/mustang/tech/ ... ghting.gif

I checked autozone for mustang flashers 91 & 99s, but they showed the same groups of flashers. It'll give you an idea of what the flasher devices look like, and then it's a matter of digging around under the hood or dashboard to find it. The good news could be that they're less than $20.

keith

Arthur McDonald · **Joined:** Fri Aug 29, 2003 1:54 am **Posts:** 2052

Thanks everybody. I replaced the solenoid once about 15 years ago. If I recall correctly, it's behind the console. I guess I'll do that and see if it helps, isn't an expensive part. I did replace the RF headlamp assembly earlier this week, and had to wiggle the RF turn signal housing a bit to make room. Will recheck the connections for that turn signal.

Vincent, you're absolutely right. I'm too old to be bothered with crap like signaling for turns. When following drivers seem my bald spot behind the roll bar in the old Mustang, they should be sufficiently warned.

Neal Harrington · **Joined:** Thu Sep 04, 2003 4:29 pm **Posts:** 106

Nobody is mentioning the elephant in the room! The chances of your being able to make a panic stop in that car make any problems with signaling inconsequential. Glad to hear you are driving it, anyway.

Chad Culbertson · **Posted:** Wed Aug 29, 2018 1:05 pm

Had a similar issue in my 2000 Grand Cherokee. Turned out it was the relay for the flashers, oddly enough the hazards worked fine too.

Apparently the relays had issues with the solder joints cracking and then working randomly, usually once they started working they would stay working for the drive but then the next day not work.

I was able to take it apart and just reflow the solder on all the connections and it solved the issue.

Arthur McDonald · **Joined:** Fri Aug 29, 2003 1:54 am **Posts:** 2052

I got a new flasher and after finally finding where the old one was hidden by the mechanic who pulled the dashboard eleven years ago to replace the heater core, fished it out and replaced it. And it didn't work. (About then I noticed that the fan for the heater-A/C wasn't working either)

Got out the owner's manual and found that the turn signals and back-up lamps are on the same fuse. (My wiring is like that in Keith's "86" wiring diagram.) Tried the back-up lamps. They don't work either. I replaced the 15 amp fuse (the old one looks OK) and no change for either the turn signals or back-up lamps. I also changed the 30 amp fuse for the blower motor (again, the old one looks OK) and no help there either.

I guess the next step is to look for a bad ground, as Patrice suggested.

Keith Roberts · **Joined:** Wed Sep 17, 2014 12:14 pm **Posts:** 31

http://www.veryuseful.com/mustang/tech/ ... iagram.gif

yikes, it sucks when your finding problems faster then getting them fixed.

the link above shows the wiring for the blower motor...
hope you have a volt/ohm meter, it's essential to track down breaks in circuits. they're readily available from Home Despot, Lowes, Harbor Freight for less than $20.

I dont see a common cause for the symptoms, so there's problable 2 or more causes.

TURN SIGNALS - BACKUP SWITCH:
- when you replaced the turn signal flasher, did you confirm that it had Lt Blu & PPL/ORG wires going to it?
- measure the voltage at fuse 5 to confirm voltage is present, and then at the PPL/ORG wire at the flasher, if measures less than 12volts, there's a break in the PPL/ORG wire.
- the backup switch is probably mounted either on the shifter linkage or in the transmission. Check the wires are connected and 12v present (PPL/ORG wire) at the BU Switch.

BLOWER MOTOR:
- depending on whats easier to get at (blower motor or blower switch or Blower Resistor) measure the voltage at either DK BLU/ LT GRN or ORG/BLK wire.
- 0 volts on the DK BLU/LT GRN, check wiring back to the selector switch
- 12 volts on DK BLU / LT GRN, check the ORG/BLK wire.
- 0 volts on ORG/BLK the motor is brunt out.
- 12 volts on ORG/BLK, then either the Blower Resistors or the Blower switch are defective.

last year the blower motor on my 91 Miata only had high speed working. found a broken wire in the resistor block. soldered it together and it was good to go!

George Bright · **Posted:** Tue Sep 04, 2018 5:51 pm

Art,
You should check that there is voltage on the fuses you have mentioned. It seems that they all are switched by the ignition switch. You may have a bad ignition switch or fusible link feeding it.

Arthur McDonald · **Joined:** Fri Aug 29, 2003 1:54 am **Posts:** 2052

George was right on the mark. Replacing the ignition switch was the fix.

Now, does anybody know of a way to unclog a heater core without taking the dashboard out?

Neal Harrington · **Joined:** Thu Sep 04, 2003 4:29 pm **Posts:** 106

Sulfuric acid flush! You didn't say you wanted it to hold water afterward.

Duane Black · **Joined:** Mon Mar 26, 2018 5:58 am **Posts:** 33

Art, you could try disconnecting bith hoses and feeding flush into it. Then, use an aur compressor with an air nozzle to blow air into the bottom of it. Once somewhat clear, you could try to rig up some kind of pump or, this one tome i blew through a hose like a reverse syphon.

Ultimately, this may or may not prove successful, depending on the severity of your clog

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