... or almost everything you need to know to install/connect turn signals. You see these asked about all the time; 'how do I connect my turns on my '58 Whazzit?' and the general answer is usually 'look up the diagram on the net and go from there'. If you're somewhat wiring savvy, that may be enough but doesn't do much for the guy that doesn't own a Whazzit. So what if you have a oddball column/switch and can't find an exact diagram, or the switch is a service replacement with different colors (don't scoff, I've seen this), the number of wires in the car don't match the column, faded colors or you're colorblind? Or just 'electrically challenged' and intimidated by all the wires? Let's try to clear the mystery.... When I said 'almost all', I'm not going to get into the really oddball stuff or European vehicles, I'm talking about units that are designed to use the rear brakes lights as the rear turns also and use a 'standard' two or three wire flasher. Most aftermarket turn signal units for early cars and pretty much all US cars originally equipped with signals are designed this way, but there are variations in wiring as the switches get newer and features were added. So lets talk about basic function. All these switches work basically the same, and there's a consistent logic in how the switching is done. You will find different numbers of wires though depending on switch features or design, so that's a good place to start; what wires you may find. First I'm going to number each wire and identify it's function (not all switches will have all wires), then I'll go through how to identify each wire using a continuity meter. If you have a late-model column with 'other' functions on it (cruise, wipers, etc), you need to separate those out. Note that these numbers are entirely arbitrary and unlikely to match however you identify your wires but are merely to show what connects to what when the switch is operated. The numbers: 1. Brake light power. This wire will come from your brake light switch. 2. Left rear brake/turn. 3. right rear brake/turn. 4. Left front turn. 5. Right front turn. 6. Turn signal power. This wire will come from the turn flasher ('L' terminal on a three wire flasher). 7. Indicator light left. 8. Indicator light right. 9. Horn. 10. Emergency flasher power. This wire will come from the emergency flasher. 11. Indicator light power. This wire will come from the turn flasher ('P' terminal on a three wire flasher). 12. Shift indicator light (some 'automatic' columns). Identifying the wires. Now let's get the meat of it. If you have fewer than six wires out of the switch, you have a turn-only switch and it isn't connected to the brake lights. Got six or more? Read the whole post and make sure you do this in the order shown or you can get hopelessly confused. Let's go... Six wires. This is your most basic switch. To identify the wires, start with the turns 'off'. You should read continuity between three wires only, and no continuity to/between the others. These are wires 1, 2, and 3 although we don't know which is which yet. Turn the switch to 'left'. One of these three will no longer read to the other two, this is wire 2. Turn the switch to 'right' and 2 now reads to one of the original three, but one won't read to the other two. The one that doesn't read is wire 3. That makes the remaining wire wire 1, or brake light power. I'll note here that no matter how many wires your switch has, this is the test to find the brake lights. You'll only find one group of three wires with the switch 'off'. To find the rest of the wires, turn the switch to 'left' again. You'll have continuity between 1 and 3 for brake, and between wire 2 and two of the other wires but not to 1 or 3. These are wires 4 and 6 although we don't know which is which yet. Note these, then turn the switch to 'right'. Now you'll have continuity between 1 and 2 for brake, and 3, 5, and 6 for turn. The one wire with no continuity to anything is wire 4, wire 6 is common to both left and right and is turn signal power, and all the wires are identified. This is the basic 'identifying test' that is done on any turn switch; any additional wires are simply added functions. In this case, if you want dash indicators for each side, connect those to wires 4 and 5. If you only want a single indicator for both sides, use a three wire flasher and connect the light power wire to the 'P' terminal on the flasher. I'll note here that a three wire flasher is only needed if you're using it to drive a dash indicator light or lights, otherwise a two wire flasher is all that's needed (sized for the lamp load of course). I'll add here that if you want/need a single dash indicator light but have an aftermarket fuse panel that won't accept a three wire flasher or don't want to add the flasher/wiring, there's a couple of ways to 'cheat' this so it works. If you use a standard 4W incandescent lamp for the indicator, then connect the wires going to the front turns to each side of the lamp (left one side, right the other) without a ground wire. The indicator light will get it's ground through the 'unused' front lamp, but the voltage drop through the small lamp is great enough that the front lamp won't light up or will glow very dimly. This won't work with a LED. As an alternative or if a LED is wanted, you can run a ground to the lamp then install a diode in each wire from the front turns before connecting both to the other side of lamp to prevent feedback into the side not 'on'. Got more than six wires? Seven wires. If you have a seventh wire and have an aftermarket switch with a built-in indicator light, this will connect to the 'P' terminal on a three wire flasher (wire 11). If you have a OEM type switch, this will likely be the horn wire (wire 9). If the horn goes through the switch, you should have a 'brush' that wipes on the steering wheel. This wire should not read to any other wire no matter what position the turn switch is in and if the steering wheel is installed with a working horn ring, should read to ground (the column) when the horn is pressed. More than Seven? At this point you're adding features. If you have emergency flashers it will be obvious. You may have separate wires coming off the switch for dash indicators, possibly even separate power for them. To find these, check like this, making sure you check each wire to all others: If you have two separate dash indicator wires, one of them will likely read continuity to wires 2, 4, 6 when the switch is on left, the other will read to 3, 5, 6 on right. These may read to their respective 'front side' wires of 4 and 5 all the time. If the wire size for 4/5 and 7/8 are the same, either one can be used for the front turn light. If you find a smaller gauge on one, use that for the indicator. If you still have an 'extra' wire and these don't read to the 'side' wires, they may have a separate power feed from the flasher 'P' terminal. Check to see if you have continuity between 7/11 (when 'on' left) and 8/11 (right) and no continuity to any other wires. Separate indicator power is rare on a OEM column, and won't be found if the switch has emergency flashers built in. This will require a three wire flasher if you want to retain this circuit, otherwise you can connect wire 11 to wire 6 and eliminate the need for a three wire flasher. If you have emergency flashers, when the switch is 'on' you'll have continuity between 2, 3, 4, 5, and 7, 8 (if present) as well as to one more wire, and this wire will be the power wire from the emergency flasher, wire 10. With the flasher 'off', this wire should not read to any other. Make sure this switch is 'off' while doing any prior checks. You might have a ground wire, but that should read to the metal column parts only, not to any other wires. If the column was out of a automatic-equipped vehicle, you may have an indicator light for gear position. This wire will connect to the dash lights. If the checks are done in order, this will identify the wiring on any switch. Do keep in mind though that switches do fail, so if you're using a used column and have issues, it may be the switch. Particularly look at columns that came out of vehicles that have done towing duty or may have had a camper installed; the extra load does shorten switch life. I'll add that if you're using a three wire flasher, the terminals are marked and must be connected correctly; 'X' is 12V power in, 'L' is load and goes to the turn switch, and 'P' is for indicator lights only. I'll note that this is 'generic' information, and while likely accurate for 99% of the US-built column switches out there, how the switches are connected to the OEM lights in the car may vary. Things like 'special' flashers, additional indicator lights on fenders or scoops, side roadway lighting when turning, sequential rear lights can have widely varying methods of factory wiring so you'll probably have to do additional research for the specific car with those features. Questions, comments welcome!