MagSport
Senior Member
For those of you wanting to install an aftermarket keyless entry system or remote start or a combination of the two, the wiring diagrams depending on the year can be a little tricky to determine and even more tricky to wire up properly. To help with this I've decided to write this thread to consolidate all of the information I used to install a Megalarm 250 remote start/keyless entry system in my '99 Ram.
Useful Wiring Information:
I found a pdf on the internet that was very helpful for my install and seems to have very useful information on the wiring colors for these aftermarket systems in Rams from 1992-2005. The only inconsistency I found was that for the lock/unlock wires in the 1999 diagram, the orange/purple and pink/purple are actually orange/green and pink/green. This may or may not carry over to other years since I cannot verify only having one truck. That information only applies to a factory installed, power door lock system. If an aftermarket door lock system is used, then the wiring will be soley reliant on on the wiring included with the aftermarket door lock motors.
The PDF with the wiring information is attached to this thread.
Door Lock Wiring:
Our factory installed power door lock systems use a 5 wire system. This basically means that the switch reverses the polarity of the current depending on if you are locking or unlocking the truck. I found this wiring diagram for general 5 wire systems on the12volt.com and used it to wire the aftermarket remote start interface. For most aftermarket keyless systems, two wires are used to signal unlock and lock pulses. It is necessary to wire in two relays to act as a "switch" to reverse the polarity depending on if the system sends a positive/negative pulse to lock or unlock.
Depending on the wiring diagrams sent with the aftermarket keyless system, the alarm- out puts will be designated by the system's installation manual. For Megalarm 250's, the wires are blue and green. The blue wire sends a (-) pulse for unlock and a (+) pulse for lock while the green wire sends a (-) pulse for lock and a (+) positive pulse for unlock. In the diagram provided by the12volt.com, the green wire in this system would be installed on pin 86 of the left relay and the blue wire would be installed on pin 85 of the right relay. For 1999 Rams with factory power locks, the lock wire is the orange/green wire and the unlock wire is the pink/green wire. Since the central timing module is so close to the work area and contains both of these wires, I used this location to splice in my wires. The CTM as its called, in 1999 Rams, is located in the right side of the knee bolster area:
It has two connectors on the bottom of it, one green, one white. The white connector contains both the lock and unlock wires needed to splice. It is neccessary to SPLICE, not cut, these wires. If these wires are set up like a standard 5 wire door lock, the unlock function of the fob WILL NOT WORK. It will actually lock the door instead of unlock it. Be sure to splice pin 30 of the left relay into the Orange/green wire on the ctm harness and splice pin 30 on the right relay into the pink/green wire. I repeat, do not cut the wires. Ground both 87a pins on each relay.
Lastly, ensure pins 85, 87 (left relay) and pins 86, 87 (right relay) are connected to constant 12v+.
It should be noted that if factory power locks are present, then a factory security system is also present. For '99 Rams the system is armed when the doors are locked (via switch or key fob) and are disarmed when the light green/orange wire in the drivers side door harness is grounded. If your remote start does not have a disarm (-) pulse output then it is necessary to connect the light green/orange wire to the same wire that is connected to pin 86 of the left relay in the12volt.com wiring diagram. Other wise, every time you use the key fob to lock and then unlock the vehicle, when the door opens the security system will go off.
Remote Start Wiring:
The aftermarket remote start/keyless system used will provide an installation manual corresponding which wires in it's harness goes where. The PDF attached to this thread will have the color codes for the wires that will be needed to connect to. For example: My megalarm 250 system has a purple wire in it's harness that must be connected to the starter wire to remote start the vehicle. The starter wire in the ignition harness is yellow. I spliced the purple wire into the yellow one. The ignition harness on our trucks follows down the steering column from the steering wheel to the main wiring junction that has to be disconnected when the dash is removed. It has a little black plastic sleeve that holds it to the steering column that can be popped open and let the ignition harness fall. In the ignition 1, ignition 2, starter wire, horn wire, 12v+, and accessory wire, are all in this ignition harness.
And those are the major things that should be considered for any aftermarket keyless/remote start system. Other little things like parking light output, domelight output, and stuff like that can vary from system to system so they were left out here but they can easily be seen in the PDF and are also available anywhere online if you look. Any questions can be posted to this thread and those of us who have done them can respond here in an effort to keep redundant posts off of the forum. Happy Ramming!
PDF
Useful Wiring Information:
I found a pdf on the internet that was very helpful for my install and seems to have very useful information on the wiring colors for these aftermarket systems in Rams from 1992-2005. The only inconsistency I found was that for the lock/unlock wires in the 1999 diagram, the orange/purple and pink/purple are actually orange/green and pink/green. This may or may not carry over to other years since I cannot verify only having one truck. That information only applies to a factory installed, power door lock system. If an aftermarket door lock system is used, then the wiring will be soley reliant on on the wiring included with the aftermarket door lock motors.
The PDF with the wiring information is attached to this thread.
Door Lock Wiring:
Our factory installed power door lock systems use a 5 wire system. This basically means that the switch reverses the polarity of the current depending on if you are locking or unlocking the truck. I found this wiring diagram for general 5 wire systems on the12volt.com and used it to wire the aftermarket remote start interface. For most aftermarket keyless systems, two wires are used to signal unlock and lock pulses. It is necessary to wire in two relays to act as a "switch" to reverse the polarity depending on if the system sends a positive/negative pulse to lock or unlock.
Depending on the wiring diagrams sent with the aftermarket keyless system, the alarm- out puts will be designated by the system's installation manual. For Megalarm 250's, the wires are blue and green. The blue wire sends a (-) pulse for unlock and a (+) pulse for lock while the green wire sends a (-) pulse for lock and a (+) positive pulse for unlock. In the diagram provided by the12volt.com, the green wire in this system would be installed on pin 86 of the left relay and the blue wire would be installed on pin 85 of the right relay. For 1999 Rams with factory power locks, the lock wire is the orange/green wire and the unlock wire is the pink/green wire. Since the central timing module is so close to the work area and contains both of these wires, I used this location to splice in my wires. The CTM as its called, in 1999 Rams, is located in the right side of the knee bolster area:
It has two connectors on the bottom of it, one green, one white. The white connector contains both the lock and unlock wires needed to splice. It is neccessary to SPLICE, not cut, these wires. If these wires are set up like a standard 5 wire door lock, the unlock function of the fob WILL NOT WORK. It will actually lock the door instead of unlock it. Be sure to splice pin 30 of the left relay into the Orange/green wire on the ctm harness and splice pin 30 on the right relay into the pink/green wire. I repeat, do not cut the wires. Ground both 87a pins on each relay.
Lastly, ensure pins 85, 87 (left relay) and pins 86, 87 (right relay) are connected to constant 12v+.
It should be noted that if factory power locks are present, then a factory security system is also present. For '99 Rams the system is armed when the doors are locked (via switch or key fob) and are disarmed when the light green/orange wire in the drivers side door harness is grounded. If your remote start does not have a disarm (-) pulse output then it is necessary to connect the light green/orange wire to the same wire that is connected to pin 86 of the left relay in the12volt.com wiring diagram. Other wise, every time you use the key fob to lock and then unlock the vehicle, when the door opens the security system will go off.
Remote Start Wiring:
The aftermarket remote start/keyless system used will provide an installation manual corresponding which wires in it's harness goes where. The PDF attached to this thread will have the color codes for the wires that will be needed to connect to. For example: My megalarm 250 system has a purple wire in it's harness that must be connected to the starter wire to remote start the vehicle. The starter wire in the ignition harness is yellow. I spliced the purple wire into the yellow one. The ignition harness on our trucks follows down the steering column from the steering wheel to the main wiring junction that has to be disconnected when the dash is removed. It has a little black plastic sleeve that holds it to the steering column that can be popped open and let the ignition harness fall. In the ignition 1, ignition 2, starter wire, horn wire, 12v+, and accessory wire, are all in this ignition harness.
And those are the major things that should be considered for any aftermarket keyless/remote start system. Other little things like parking light output, domelight output, and stuff like that can vary from system to system so they were left out here but they can easily be seen in the PDF and are also available anywhere online if you look. Any questions can be posted to this thread and those of us who have done them can respond here in an effort to keep redundant posts off of the forum. Happy Ramming!
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