No turn signals

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Joined
Dec 28, 2014
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Location
Washington Twp. Mi
My Car
1972 Mach 1 Q Code
So all of a sudden my turn signals quit working. Neither side works. I checked the fuse, but it looks good. I have emergency signals and all other lights are working, including brake lights. I thought it was the flasher relay so I went and got another one. Still no signals. I even tried the emergency relay which I know works, but still no turn signals. I have a relatively new turn signal harness, so I’m not sure what is wrong.
If someone can give me some idea as to what might be wrong I will be very appreciative! Thanks
 
That's weird. Do you have LED bulbs in the turn signals? If so, it may be the wrong flasher, you might need one of these below. That or the polarity could be wrong. Just guessing but I assume they worked before. Your four ways work, correct? so bulbs are ok. Could be bad ground on the signal flasher. Guessing once again.
 

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Based on what you said, it sounds like it is down to the switch, a connector, or a wire is open to or from the flasher. I would suspect the new harness first. Breakout the multimeter. Do you have the electrical assembly manual? Chuck
 
The turn signals and the emergency flashers use the same wiring from the turn signal switch to the bulbs, so you know the wiring and bulbs are good. Like Chuck said get out the multimeter and check for voltage on both sides of the fuse, with the ignition switch on. Just because a glass fuse looks OK doesn't mean it's good. The fusible link in it may not be making contact with the metal end caps. The emergency flasher uses a circuit breaker, separate from the turn signal flasher, which uses the fuse.
 
+1 with Don on the fuse. Unless it clearly shows being blown the only true way to check a fuse is with a meter or test light. I have chased several ghosts over the years because of being too lazy to properly check a fuse.
 
That's weird. Do you have LED bulbs in the turn signals? If so, it may be the wrong flasher, you might need one of these below. That or the polarity could be wrong. Just guessing but I assume they worked before. Your four ways work, correct? so bulbs are ok. Could be bad ground on the signal flasher. Guessing once again.
No led turn signal lights
 
Is the fuse for the radio the same as the turn signal?
Yes, along with the backup lights and windshield washer. If your radio works, and has the original wiring, the fuse is obviously good. The next thing I would check is the new wiring harness, as stated many times, new doesn't mean good, a connector or wire connection may have pulled apart.
Circuit 296, white wire with purple stripe, provides power from the fuse to the flasher, circuit 44, light blue wire, runs from the flasher to the turn signal switch.
 
Yes, along with the backup lights and windshield washer. If your radio works, and has the original wiring, the fuse is obviously good. The next thing I would check is the new wiring harness, as stated many times, new doesn't mean good, a connector or wire connection may have pulled apart.
Circuit 296, white wire with purple stripe, provides power from the fuse to the flasher, circuit 44, light blue wire, runs from the flasher to the turn signal switch.
Ok thanks Don, it must be something in the harness then.
 
I am not sure if you have a schematic or not for the 71-73 Mustang. One of the attached files is a snippet for 1973 Mustangs that I annotated that covers the turn signal and 4-way emergency flasher circuits, all the way back to the power feeding the circuits for both, including the fuse block (see both pages 1 & 2) and a circuit breaker in the Relay Bar area of those Mustangs. I attached some other files that cover the Relay Bar area in detail in case you need it.

The 73 schematic is largely the same for 71-72 Mustangs, with some minor differences that ought not impact your circuits re: turn signal and 4-way emergency flasher operation. If you feel this schematic is not appropriate for your car (71 or 72) let me know and I will put together a snippet from earlier schematics.

I hope this is useful to you.
 

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Ok I have found the problem. I have a loose wire in the turn signal harness. I wiggled the harness around some and they started working again. I did do this before but they still wouldn’t work. I still need to pinpoint the problem but at least I know where to look. Electrical problems are my week point when it comes to cars.
Thanks again for all the replies and info on this problem! You guys are great!
 
I am not sure if you have a schematic or not for the 71-73 Mustang. One of the attached files is a snippet for 1973 Mustangs that I annotated that covers the turn signal and 4-way emergency flasher circuits, all the way back to the power feeding the circuits for both, including the fuse block (see both pages 1 & 2) and a circuit breaker in the Relay Bar area of those Mustangs. I attached some other files that cover the Relay Bar area in detail in case you need it.

The 73 schematic is largely the same for 71-72 Mustangs, with some minor differences that ought not impact your circuits re: turn signal and 4-way emergency flasher operation. If you feel this schematic is not appropriate for your car (71 or 72) let me know and I will put together a snippet from earlier schematics.

I hope this is useful to you.
Thanks very much for sharing these great wiring diagrams for 71-73 Mustangs. -Wanted to ask can you still purchase the 158/159 switch relays above the glovebox on the relay "Panel".? I know my door buzzer stopped working after i replaced the turn signal switch....With 51 year old wiring it could be many things why my turn signals/fuel gauge and wipers do not operate. The wiring diagrams will help and will work on testing with a test light and multimeter and replace the 158/159 relays to start with...The flashers work,horn works,headlights work.-Thanks very much for the help Vintage auto lovers.-
 
I am not sure if you have a schematic or not for the 71-73 Mustang. One of the attached files is a snippet for 1973 Mustangs that I annotated that covers the turn signal and 4-way emergency flasher circuits, all the way back to the power feeding the circuits for both, including the fuse block (see both pages 1 & 2) and a circuit breaker in the Relay Bar area of those Mustangs. I attached some other files that cover the Relay Bar area in detail in case you need it.

The 73 schematic is largely the same for 71-72 Mustangs, with some minor differences that ought not impact your circuits re: turn signal and 4-way emergency flasher operation. If you feel this schematic is not appropriate for your car (71 or 72) let me know and I will put together a snippet from earlier schematics.

I hope this is useful to you.
Thanks very much for posting all the great wiring diagrams for 71-73 Mustangs and wanted to ask if my wipers not working along with fuel gauge,turn sugnals,etc could be related to a bad turn signal "Relay" switch and is this switch located on the "Switch-Relay" tray above the glove box.-Thanks very much.-Joe K.-
My 4-way flashers work fine along with the headlights and Horn. I think my factory am/fm radio is burned up and my heater motor is more than likely burned up as well being over 50 years old.-I will be more than happy to have working turn signals and wipers again so i can run the car back through the Delaware DMV this spring when i receive my new title and registration.-Looking to replace all the relays on the tray above the glove anyways as i'm in the processs of restroing the car anyway.-Thanks for all the help classic vehicle owners.-Joe K.-
 

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