Brake lights turn signal issues

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morevair
Posts: 49
Joined: Mon Oct 30, 2017 7:07 pm

Brake lights turn signal issues

Unread post by morevair » Sun Dec 03, 2017 12:23 pm

Hey All,

I'm having some lighting issues and was hoping to get some help figuring out the issue...
1966 Corsa...
tail lights work,
front signals work,
backup lights work,
plate light works,
brake light don't work,
rear signals don't work,
Changed the bulbs, they appear good...

Any help is appreciated...

jimsmith2354
Posts: 2
Joined: Fri Jun 16, 2017 1:04 pm

Re: Brake lights turn signal issues

Unread post by jimsmith2354 » Sun Dec 03, 2017 1:59 pm

I would suggest going after the turn signal switch contacts with cleaner.

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bbodie52
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Re: Brake lights turn signal issues

Unread post by bbodie52 » Sun Dec 03, 2017 3:54 pm

morevair wrote:Sun Dec 03, 2017 2:23 pm

I'm having some lighting issues and was hoping to get some help figuring out the issue...
1966 Corsa...
tail lights work,
front signals work,
backup lights work,
plate light works,
brake light don't work,
rear signals don't work,
Changed the bulbs, they appear good...


Any help is appreciated...
brake light don't work
rear signals don't work


You are looking for a common thread that would affect both the rear turn signals AND the rear brake lights. The rear turn signals and the rear brake lights utilize the same bright filament in each 1157 bulb on both sides of the vehicle. The taillights in each of those sockets utilize the other filament in each 1157 bulb. Both use the same socket on each side for a ground return, so you know that the ground connection for each socket is good because the taillights work.

The schematic diagram below is for a 1965 Corsa. I don't have a combined schematic for the 1966 Corsa. The wiring for both model years is essentially the same with the exception of the color codes, so the color codes I mentioned in the schematic will probably not match the wiring color codes in your 1966 Corsa.

Left-click the image (one or two times) to enlarge it for better viewing or "Pan & Scan"...
1965 Corvair Corsa Full Schematic (Rev. D).jpg
1965 Corvair Corsa Full Schematic
CORVAIR COMBINED WIRING SCHEMATIC DIAGRAMS
:link: viewtopic.php?f=225&t=12968

In the diagram, the wire labeled 20 B/Y (20gauge black with yellow stripe) can be found connected to the left side tail and directional lamp. This is the wire that powers your left side turn signal/stop lamp. The other wire, labeled 20 BRN/T (20gauge brown with tan stripe) is extended from the left tail lamp to the right tail lamp, and powers both tail lamps. The right side turn signal/stop lamp is powered by a wire labeled 20 DG (20gauge dark green). The two sides are wired individually because of the need to be able to control the turn signals individually.

The rear brake lights both have a common point of origin at the stop lamp switch that is activated by the brake pedal (connected to switch post B+ in the image below). With the turn signal switch in the off position, the connecting strips between the B+ post and the left rear post (LR) and the right rear post (RR) are normally connected to pass the voltage from the stop lamp switch at the brake pedal straight through the turn signal switch and on to the rear filaments in the 1157 bulbs. Activating the turn signal for right or left temporarily interrupts the connection on the selected side so that is no longer is in contact with the B+ post. Instead, a connection strip moves to come in contact with the turn signal voltage (TS+) that originates at the fuse block from the turn signal flasher. The same motion also pushes the connection strip into contact with either the right front (RF) or the left front (LF) post, so that the intermittent (flashing) on/off voltage from the turn signal flasher is connected to both the front and rear 1157 bulbs on the selected side. The other side remains in contact with the stop lamp switch at the brake pedal for the rear 1157 bulb that has not been reassigned temporarily to the turn signal function. This would allow a driver who was following behind to see a flashing turn signal on one side and a continuous stop lamp indication on the other side at the same time, which would occur if the Corvair driver was applying the brakes in a turn.

Since both of your front turn signals are functional when activated by the turn signal switch, you can assume that the turn signal voltage at the TS+ post is being properly provided by the flasher in the fuse block, and that the turn signal switch mechanism is establishing the proper connection between TS+ and either RF or LF to take care of the right or left front turn signal. You also know that the connection between the turn signal switch in the bright filaments of the rear 1157 bulbs is never making it to those bulbs, regardless of the power source (stop lamp switch or turn signal flasher). While there could be a problem internally within the turn signal switch, I would recommend checking the multi-connectors in the circuit path first. If you look at the schematic diagram you will see a curved eight pin multi-connector below the fuse block in the diagram. This curved multi-connector is the connection point on the steering column between the turn signal switch and the rear 1157 bulbs (20 DG and 20 B/Y). This curved multi-connector is one possible circuit interruption point. The two wires continue on and pass through a 12 pin multi-connector behind the dashboard that connects to the rear wiring harness. The two wires continue on towards the rear of the car and pass through yet another 12 pin multi-connector in the engine compartment.

If you have a multimeter, you can separate the two halves of the plastic multi-connector in the engine compartment and check for brake or turn signal flasher voltage on the firewall side of the multi-connector at the appropriate pins. If you detect brake light voltage coming into that connector when someone steps on the brake pedal, you know that the circuit is good all the way to that connector. Check for corroded or bent/damaged pins within the connector shell that would be causing a circuit interruption at that point. If you do not find voltage there, you will have to check further forward at the two connectors that are behind and under the dashboard. If your testing fails to locate stop lamp voltage or turn signal voltage at the curved connector on the steering column, your problem is likely within the turn signal switch itself and you will have to remove the steering wheel to access that switch and examine/replace a faulty turn signal switch.

Late Model (LM — 1965-1969) Corvair, the "guts" of the turn signal switch are buried in the steering column.
Image
Late Model Corvair Instrument Panel Wiring Connector.jpg
Late Model Corvair Instrument Panel Wiring Connector
1965-1969 Corvair Engine Compartment Wiring Harness Segment - Multi-pin Connector.jpg
1965-1969 Corvair Engine Compartment Wiring Harness Segment - Multi-pin Connector
1965-1969 Corvair Engine Compartment Wiring Harness Segment - Multi-pin Connector.jpg (34.19 KiB) Viewed 140 times
1965-1969 Corvair Engine Compartment Wiring Harness Multi-pin Connector.jpg
1965-1969 Corvair Engine Compartment Wiring Harness Multi-pin Connector
1965-1969 Corvair Engine Compartment Wiring Harness Multi-pin Connector.jpg (33.79 KiB) Viewed 140 times
:link: http://www.corvair.com/user-cgi/catalog ... IN&page=87
Image

Image
Part number C862: 65-66 & 64-65 FC DIRECTIONAL SWITCH
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

morevair
Posts: 49
Joined: Mon Oct 30, 2017 7:07 pm

Re: Brake lights turn signal issues

Unread post by morevair » Sun Dec 03, 2017 6:02 pm

Brad,

Thanks for the great information... I pulled the wheel and inspected and cleaned the switch, looks can be deceiving but it look to be in good shape... I've order a new engine harness (the original on is a bit crispy) so I'll start trouble shooting with a meter after the new harness is in. Thanks very much...

morevair
Posts: 49
Joined: Mon Oct 30, 2017 7:07 pm

Re: Brake lights turn signal issues

Unread post by morevair » Sun Dec 03, 2017 9:48 pm

Brad,

Beginners question ( which I am) how do you separate the electrical connections ? I see the main connection on the engine harness has some push tabs to disconnect ( although one pushes and the other one doesn't...Murphy's law) but a lot of the connectors I don't see any "release" mechanism... are they just "yank" ? I don't want to break anything more than I have to... (I thinks I broke my horn with the steering column disassembly... Oh well.. live and learn)...

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bbodie52
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Re: Brake lights turn signal issues

Unread post by bbodie52 » Mon Dec 04, 2017 7:41 am

ImageImage

Most electrical multi-connectors are keyed in some way so that they can only be plugged in with a specific orientation. They also have one or two locking tabs to secure the two halves of the plastic shell together. The locking tabs are sometimes difficult to depress and a small flat bladed screwdriver may help.

The aging multi-connector in the Corvair engine compartment is usually the most troublesome. It is exposed to heat, vibration, and moisture that can cause corrosion internally between some of the metal components that can cause a breakdown in electrical continuity. Some of the circuits are live and not controlled by an electrical switch, so some caution must be taken when cleaning or testing the electrical contacts when the two halves of the multi-connector have been separated. You may choose to disconnect the negative battery terminal if you are cleaning or straightening the internal connectors to prevent an electrical short.

With the curved connectors disconnected at the steering column, and ohm meter can be used to check for proper electrical continuity by carefully identifying each of the wires connected to the turn signal switch and then checking to see if the proper connections have been established as the turn signal switch is moved to each of its three possible configurations. For example, on the 1965 Corvair wiring harness the 20 B/W should show continuity with both the 20 B/Y (left rear brake light) and the 20 DG (right rear brake light) terminals with the turn signal switch in the center (neutral) position. Moving the turn signal switch to activate the right turn signal should show continuity between the 18 PPL (turn signal flasher input) and both the 20 DG (right rear) and the 20 DBL (right front). Moving the turn signal switch to activate the left turn signal should now show continuity between the 18 PPL wire switch terminal and both the 20 B/Y (left rear) and the 20 B/LBL (left front) terminal. The schematic diagram should help you to determine the purpose of each of the wires (stop lamp switch input or turn signal flasher input for source voltages, and the appropriate outputs for the left and right, front and rear bulb connectors. Proper use of and ohm meter to check continuity through the turn signal switch can be done without having to dismantle the steering wheel and steering column to access the turn signal switch mechanism.

If the turn signal switch connectors check out with an ohm meter, each of the remaining multi-connectors in the circuit would have to be checked to determine which multi-connector may be causing a loss in electrical continuity. Shorted or melted wires or cut wires in the wiring harness are also possible, but less likely to have this type of physical damage.

It is important to understand what "normal" looks like in any electrical circuit by carefully studying the schematic wiring diagram. If you understand how the circuit is supposed to operate, it makes it easier to troubleshoot and diagnose the cause of a problem using logic and a multimeter.

Image
Brad Bodie
Lake Chatuge, North Carolina
Image 1966 Corvair Corsa Convertible

morevair
Posts: 49
Joined: Mon Oct 30, 2017 7:07 pm

Re: Brake lights turn signal issues

Unread post by morevair » Sat Dec 09, 2017 3:05 pm

Thanks for the info... I'm in luck, one of our local Corvair enthusiast , who is also and electrical Engineer, has offered to help me troubleshoot the problem... Man Corvair People are the BEST!!!

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