At first glance, the STS-1 Sequential Turn Signal System kit appears to be very simple. There are two separate electronic units that have 5 wires each. The wires are of various colours and the units are sealed in some type of plastic or vinyl material. There is also a bag included that includes some electrical wire, various connectors and some tie wraps. There are quite good instructions included and the schematic diagram seems very thorough and straight forward. The one oddity with the schematic is however that it is missing nearly all of the wire colour labels. Those are easily had from another page of instructions included in the kit.
I will be installing the unit in my 1978 Newport. I am certain that the wiring procedures will be nearly identical. There are basically two ways to install the unit. The first way would result in the signal lights sequencing when activated. The second way results in the turn signals AND brake lights sequencing. I am not crazy about messing with the brake lights because of safety and legal issues but since they simply sequence once and then stay on, it doesn't seem like a big problem. One of the biggest reasons to install it the second way is that it is much easier and requires no wiring outside of the trunk.
The Newport does have three bulbs in each tail light assembly but the centre one is not normally a signal light. This can easily be overcome because in her wisdom, Ma Mopar has fitted the centre light with the same, twin filament socket that the inner and outer lights have. The only shortcoming is that the centre light does not have both wires installed so I needed to get another one from another car (handy 77 NYB parts car in the yard) and install it into the centre socket.
Installation: I will be describing here only one side of the installation because both sides are identical. The principle is quite simple. As far as the stock wiring goes in the car, there is only one wire that powers the signal lights. (remember I am talking about one side only so, in all, there are two, one for each side. Remember that because I won't be taking the time to remind you again.) The installation of the STS-1, goes like this.
Sequenced Signals AND Brake Lights: 1. Twist the ends of the gray and red wires together and attach them to the signal light wire that feeds the inner bulb. (do not cut the car's wire at this point.) 2. Cut the wire that goes to the centre signal light bulb and connect the bulb side of that wire to the white wire from the STS-1. (wrap the other end of the signal light bulb wire up in tape so it will not short on anything) 3. Cut the wire that goes to the outer signal light bulb and connect the bulb side of that wire to the blue wire from the STS-1. (wrap the other end of the signal light bulb wire up in tape so it will not short on anything) 4. Connect the black wire from the STS-1 to any suitable ground point (I used one of the mounting studs for the tail light assembly) 5. repeat for the other side of the car.
Sequenced Turn Signals Only: 1. Connect the grey wire to any point in the turn signal wiring that goes to the FRONT signal bulb. What you need here is a point that has turn signal power ONLY, not brake lights. There is normally no source for this at the rear of the car so you will have to connect it either under the dash or at he front of the car. See your FSM or local IML wiring guru for which wire to tap into. Do not cut the signal wire you tap into, just use a Quick Splice Connector as described on Page 4 of the directions. 2. In the trunk again, connect the red wire to the signal light wire that feeds the inner bulb. (use a Quick Splice Connector here too, do not cut the stock wire) 3. Cut the wire that goes to the centre signal light bulb and connect the bulb side of that wire to the white wire from the STS-1. (wrap the other end of the signal light bulb wire up in tape so it will not short on anything) 4. Cut the wire that goes to the outer signal light bulb and connect the bulb side of that wire to the blue wire from the STS-1. (wrap the other end of the signal light bulb wire up in tape so it will not short on anything) 5. Connect the black wire from the STS-1 to any suitable ground point (I used one of the mounting studs for the tail light assembly) 6. repeat for the other side of the car.
Basic Suggestions: 1. Leave your wires as long as is practical. Short wires are very hard to work with. 2. Use shrink tube or at the very least black electrical tape to seal all your connections, even the Quick Splice Connectors.
Adjustment: There is an adjustment that you may have to make. You need to be sure the signal flasher gives the STS-1 enough time to sequence through all three lights in one flash before it shuts off and flashes again. The sequence needs to be this... Flasher on - STS-1 inner, middle, outer, Flasher off...repeat. The STS-1 that I installed takes less than a second to light all three signal lights. The flasher was sped up slightly because I added the third signal light bulb to each side. I found that this caused the outer bulb to light for a very short period. There are two ways to resolve this. You can replace your flasher unit with a heavy duty one. These do not depend on the total resistance of the signal light bulbs to determine the flash rate. You can also try to adjust the existing flasher unit to slow it down a bit. There are good instructions in the kit for doing the latter. To do this, simply take the cover off the flasher and bend one of the contacts outward just a little. I recommend just replacing the flasher with a heavy duty unit.
When you've completed all this, you should have a nifty 3-way set of sequential turn signal lights on your favorite Mopar. ENJOY!