Turn Signal Switch Wiring Question

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don4407
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Joined: Mon Oct 20, 2014 6:47 pm

Turn Signal Switch Wiring Question

Post by don4407 »

Hello, I could use some assistance with the turn signal switch wiring. I'm using a 63? Corvair steering column in my 31 Model A Ford hot rod build. I would like to retain the original Corvair turn signal mechacnizeim but I have no clue of how to wire it. Attached is a photo of the switch plug, can anyone tell me witch pin goes where? Is the male portion of the plug available? The horn button photo is to ID the column year because I'm not sure. Thanks
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IMG_3531.JPG
IMG_3529.JPG
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bbodie52
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Re: Turn Signal Switch Wiring Question

Post by bbodie52 »

What follows is an explanation of the turn signal and brake/tail light system in a 1962 Corvair. The 1963 schematic is very similar. Hopefully this explanation and these wiring diagrams will provide a good starting point for you...

BRAKE LIGHT CIRCUIT FUNCTION
With reference to the TURN SIGNAL SWITCH in the first schematic diagram below, the 20p and 20v leads route to the engine compartment Left and Right Stop/Turn Signal lamps. These same bright lamp filaments provide BOTH Stop Lamp AND Turn Signal functions. When the Turn Signal lever is off, BOTH of the 20p and 20v lamp wires are internally connected within the turn signal switch to the 20n wire coming from the Stop Lamp switch at the brake pedal. Stepping on the brake pedal applies voltage to the 20n lead that is connected to the turn signal switch. The voltage passes through the turn signal switch, and on to BOTH the 20p and 20v wires, and then on to the rear tail lamps to illuminate the bright filaments in both lamps.

TURN SIGNAL CIRCUIT FUNCTION
When the driver activates either the left or right turn signal, that specific connection that is normally wired within the turn signal switch to the brake light (20n) lead is temporarily disconnected. It is then switched to the turn signal function, and intermittent on/off flashing voltage from the 20y lead is cross-connected to either the left (20p) or right (20v) lead, depending on whether the left or right signal was switched on by the driver. The unused turn signal/brake lamp bulb remains connected to the 20n wire coming from the brake pedal, so that the side that is not flashing as a turn signal will still function as a brake light. When the turn is completed and the turn signal is cancelled, the turn signal lever returns to the OFF position, and the brake function connection is restored to BOTH tail lights.

You can see that everything that is connected to the tail light bright filaments is routed through the turn signal switch. The brake light switch depends on the routing of electricity through the turn signal switch. When the turn signal switch is not activated, brake light voltage can pass right through it to the tail lights. When the turn signal switch is activated, control of either the left or right bulb is taken from the brake light switch and temporarily given to the turn signal switch, so that flashing voltage can be applied to the appropriate rear tail lamp (and to the matching front turn signal lamp).

TROUBLESHOOTING
Since the turn signal switch is common to BOTH the brake and turn signal functions, neither will work if the turn signal switch or connections to the tail lights are bad. If neither the brake or turn signal lights ever works, the fault is in the turn signal switch OR the connections to the tail lights. If the turn signals work but the brake lights do not, the fault would be with the brake light switch or its wiring. You must determine, by using a voltmeter, if the voltage directed to the 20p and 20v leads is actually getting out of the turn signal switch. If you see that brake or turn signal voltage coming out of the turn signal switch, but the lights still don't come on, the the problem is further back, toward the rear lamps, with either a bad connector, bad wiring, or a bad ground at the tail lamp sockets (assuming that the bulbs themselves are OK). You must continue to trace the brake light voltage, if you see it coming out of the turn signal switch leads, to find out just how far it is getting, and where it stops.

TURN SIGNAL SWITCH CONNECTIONS
When looking at the turn signal switch in the schematic below, you will see six pins. The left two pins are connected to the front lamps in the trunk. These function as turn signal lamps only. The right two pins are connected to the rear lamps in the engine compartment. These function as BOTH turn signals and as brake lamps. The middle two pins are the source of power for the lamps. The top-center 20y lead provides intermittent flasher voltage to the turn signals (front and rear) when the turn signal lever is activated by the driver. The bottom center 20n lead provides brake stop lamp voltage to the rear lamps only, whenever the brake pedal is pushed and the brake stop lamp switch is closed, to allow voltage to pass through it.

TO ENLARGE EITHER DIAGRAM, CLICK ON THE PICTURE WITH THE LEFT MOUSE BUTTON
1962 Turn Signal & Stop Lamp Wiring (Passenger Compartment).jpg
1962 Turn Signal & Stop Lamp Wiring (Engine Compartment).jpg
For comparison to the 1962 schematic diagrams (above), I have included the 1963 diagrams (below, shaded in turquoise). A copy of the applicable section of the 1962-1963 Corvair Shop Manual Supplement to the 1961 Corvair Shop Manual is also attached.
1963 Corvair Instrument Panel and Body Wiring Diagram
1963 Corvair Instrument Panel and Body Wiring Diagram
1963 Corvair Engine Compartment Wiring
1963 Corvair Engine Compartment Wiring
Attachments
1962-1963 Supplement - Chevrolet Corvair Shop Manual - Section 8 - Electrical Systems.pdf
1962-1963 Supplement - Chevrolet Corvair Shop Manual - Section 8 - Electrical Systems
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Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible
don4407
Posts: 5
Joined: Mon Oct 20, 2014 6:47 pm

Re: Turn Signal Switch Wiring Question

Post by don4407 »

Thanks so much for the schematic and information , it gives me a place to start.
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