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Emergency flasher 1967 Fastback

Remco Steen
New User
Posts: 3
Joined: 02/14
Posted: 02/13/14 02:21 PM

I have a 67 Mustang fastback and since I have it (15 years), I have the following electrical problem.
My hazard flashers dont work. My brake lights work fine and all the turn signals are also o.k.
When I pull the hazard lights knob, nothing happens. But if I then step on the brake pedal, my rear brake lights/hazards come on illuminating continuously together with my both front turn signal lights ( also not blinking, but illuminating continuously). When I release the brakes, all lights go out.
Years ago I changed the emergency warning flasher and brake pedal switch, but that didnt help. I checked the voltage on the flasher unit, and it gets 12 volts (permanent).
I hooked up a new turn signal switch to my underdash harness this week, but also then the problem is present.
I also renewed the front parking light units recently.
Grounding of the taillights is ok.

Anyone has an idea what the problem could be?

Regards, Remco (The Netherlands)  

Post Reply
Posts: 101
Joined: 10/13
Posted: 02/14/14 02:32 AM

first a wayne secret... i have a bunch of test lights..  one that i ONLY use on lighting and turn signal work looks like this...  but i modified it.. i swapped out the tiny bulb for a 211-2 bulb..  and i am very careful to NOT use it for more than a few seconds with the bulb on.  the 211-2 bulb gets REALLY REALLY Hot as it draws enough current to make the turn signal or hazard flashers work by just probing them..   i had it hooked up to positive on the clip one day and walked away to answer the phone.. it slipped and touched ground.  the bulb came on ..i smelled melting plastic.. doh!!!! it was all melted.. at least there was no carpet in that car at that point.

HF 30779 Zpsc0772e7e

let me describe how flashers work inside...

there is a piece of spring steel that has a slight bend.. its has a coil of wire around it..  

when you activate the circuit.. the current flows thru the coil winding and heats up the curved metal.. this because the metal is laminated out of two different metals with different expansion rates UNBENDS.. the unbend opens a set of contact points cutting the power to the circuit. the metal cools and snaps back.. making contact and completing the circuit again..  heating the spring until it snaps open again...

the flasher does NOT like to work when plugged in backwards..

swap flasher locations. usually #552 flashers are used in the hazard position. there are a bunch of different flasher numbers...

i am thinking that your hazard flasher is either plugged in backwards or bad..

you can also check for power into the turn signal switch.. let me look at the wiring diagrams.

the wiring from the hazard flasher to the turn signal switch connector is not marked. but it is white and RED going thru the connector and up to the switch..

is your hazard flasher remotely mounted in the glove box??? or on a separate dash knob????  so..

probe the hazard flasher.. do you get power on one wire with it disconnected..

with it connected and you probe the other side..  do you get power there..  when you probe the white and red wire on the column side of the turn signal connector do you have power there????

according to my diagram.. the hazard fuse also powers the blue and black wire to the clock.. but NOT the brake light switch as it is in many other cars..

the stop light switch is powered via the green and red wire from the headlight switch.. and that also supplies power via a yellow wire into the turn signal connector that is for the horn button..

the green wire is the brake light switch output to the turn signal switch

the turn signal wire is BLUE..

i should know all these by heart as i just helped a friend do the collapsible column swap from a 68 torino to his 66 fairlane 500.   i actually send him out and i spliced together a curved connector to the proper 66 fairlane connector so he could swap them back  if he wanted and i did not have to cut any wires..

don't have a 211-2..   look at the courtesy lights under the dash.. please don't touch them if they have been on.. the bulb lens is quartz as i recall.. so it can get instant FRY the fingers HOT..  dome lights .. back seat lights in the C pillar also use these bulbs.. .. you can get pointed versions out of a lot of european cars.. use washers and cut spring on each end to center them in your customized test light..

please post how it works out.. i drop thru here several times a day usually.. or night.  

Post Reply
Posts: 101
Joined: 10/13
Posted: 02/14/14 02:36 AM


perhaps this will help..  

Post Reply
Remco Steen
New User
Posts: 3
Joined: 02/14
Posted: 02/14/14 08:09 AM

Hai Wayne!
Thx for all the info. Next two weeks I don't have time for the car  Frown  , but after that I'll be into investigation again. If I find it, I'll let you know....

Regards Remco  

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