Intermittent failure of turn signals
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Mountain Pass
Joined: Mar 2008
Posts: 166
Likes: 38
From: SW GA
Intermittent failure of turn signals
So I recently replaced the MFS and the signal flasher thinking the electronic one had failed. Everything worked for about a week and now it has quit again. I have studied the wiring diagram and I do not have a clue what could be fouled up. Truck has not been butchered as I found it w/ less than 95K original miles. Been driving it for right at 2 yrs this July. The emergency side works fine so I know the bulbs are good as is the ground or they wouldn't work. I have verified w/ test light that power is making it to the flasher socket in fuse panel. i've swapped em. flasher (original wagner flasher) to the turn signal side w/ no change. I am at the point where I need to just turn the signal on and start wiggling everything from the trailer plug (could be a tee splice issue) to the brake light switch and the ignition switch. Fuse has checked in the fuse panel so I am about out of ideas. Anyone got anything else I should inspect?
Hotshot
Joined: Jul 2020
Posts: 10,400
Likes: 2,606
From: Near Salt Lake City
Who made the new multi-function switch?
I had to put 3 Autozone ones in my buddies Lincoln before we got pissed and found a NOS Ford one on Ebay
His would do the same thing, work then not work and was plugged in good
You might check the plugs on the back of yours, as that is the most common problem IMO
Sometimes those wires get pulled out of the connector, and the connector would be in place, but the pulled out wires would not make contact
Intermittent flashers are common too, swap your TS flasher with the one for the hazards, the hazard flasher generally never gets used, and they are usually like brand new
I had to put 3 Autozone ones in my buddies Lincoln before we got pissed and found a NOS Ford one on Ebay
His would do the same thing, work then not work and was plugged in good
You might check the plugs on the back of yours, as that is the most common problem IMO
Sometimes those wires get pulled out of the connector, and the connector would be in place, but the pulled out wires would not make contact
Intermittent flashers are common too, swap your TS flasher with the one for the hazards, the hazard flasher generally never gets used, and they are usually like brand new
Thread Starter
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Mountain Pass
Joined: Mar 2008
Posts: 166
Likes: 38
From: SW GA
Who made the new multi-function switch?
I had to put 3 Autozone ones in my buddies Lincoln before we got pissed and found a NOS Ford one on Ebay
His would do the same thing, work then not work and was plugged in good
You might check the plugs on the back of yours, as that is the most common problem IMO
Sometimes those wires get pulled out of the connector, and the connector would be in place, but the pulled out wires would not make contact
Intermittent flashers are common too, swap your TS flasher with the one for the hazards, the hazard flasher generally never gets used, and they are usually like brand new
I had to put 3 Autozone ones in my buddies Lincoln before we got pissed and found a NOS Ford one on Ebay
His would do the same thing, work then not work and was plugged in good
You might check the plugs on the back of yours, as that is the most common problem IMO
Sometimes those wires get pulled out of the connector, and the connector would be in place, but the pulled out wires would not make contact
Intermittent flashers are common too, swap your TS flasher with the one for the hazards, the hazard flasher generally never gets used, and they are usually like brand new
Lead Driver
Joined: Jun 2021
Posts: 5,219
Likes: 805
The new switch is an Autozone one and it was not local. I had put an unknown switch from JY in about 6 months ago only because the stalk had a plastic door that kept falling off. It had no markings and I snagged it because it looked nearly new. I still have it so I may direct it and determine what is going on. I already tried swapping the em flasher which was original ford (made by wagner) and it made no change. I will check the wires in the connector as that is a possibility due to the tight angle the wiring is subject to.
If you HOLD the switch in the direction with a bit of force, does it work?
Ive had where I need to operate the lever at the speed I want it to blink and thats from the column cancel cam (pre 92 columns only)
I used to have that problem intermittently, i have since lost the problem, I think the only thing ive done is pulled the large connector on the cab, cleaned terminals ,and reseated and also possibly cleaned up body grounds and the frame ground.
Thread Starter
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Mountain Pass
Joined: Mar 2008
Posts: 166
Likes: 38
From: SW GA
FIXED!I I pulled the switch and checked the circuits 44 w/ 9 & 3 for left side and 5&2 for right side. With switch activated those circuits were connected. So then while unplugged i verified pin 44 in the plug was not getting power from the flasher(new). Unplugged flasher and w/ key in run, I am getting power on one terminal. Pop in an electronic one and it starts working.
Last edited by generalee; May 24, 2026 at 03:05 PM.
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