This is a rather large post, trying to decipher everything. I'm trying my best to give credit where appropriate as well as explain the differences of the options that have been discussed.
Refer to this page to understand what gauge wire you need for the amps and wire length:
http://www.offroaders.com/tech/12-volt-wire-gauge-amps.htm This chart explains why certain wire gauges are used/recommended.
The gauge wire used and the fact that the current for the motors goes through the switches is the main reason we're having this discussion.
Scenarios of wiring power windows with key differences listedFactory - Problematic as we all know.
- Only one relay used, it provides 14 gauge power through the factory switches to the power window motors.
- Heavy current flows through switches which overtime cannot keep up to the task.
- 14 gauge power flowing to both motors at the same time is barely sufficient.
Painless Kit: Improvement on factory wiring adding 4 relays (like what ta78w72 / lee01 have discussed/documented)
- Removes window motor power from going through the switches.
- Purchasable plug-in play solution.
- Wires into the factory fuse box the same way the factory power windows is wired in.
- Includes ground wires from door to inside chassis.
ta78w72 Design: A design like the Painless 4 relay setup designed for DIY folks.
- Extremely cheaper than the Painless kit.
- Gives you the flexibility to wire it how you want, mount relays where you want, etc...
lee01 Design: A readable schematic version of what ta78w72 designed, with input from the forum. (For reference, this is the thread where Lee put together his diagram with help from ta78w72 and others others:
http://www.78ta.com/HTAF/index.php?topic=8202.0) This design is fully documented here:
http://www.78ta.com/HTAF/index.php?topic=40530.0
- Heavier gauge wire directly from battery with appropriate 30 amp fuse inline.
I believe the main difference between lee01 and ta78w72 is their opinion on where the power source comes from (direct from battery vs from fuse box).
angelo Design: That's me! Removes old relay. Not in the image is my recommendation on adding a fusible link if wired to the alternator.
All I did was recommend that the old relay is no longer needed, some folks agreed on my thought so I modified the drawing as such. I also recommend if running from the alternator to include a fusible link (engine side) in addition to a 30 amp fuse. I also advocate for 12 gauge wire (rather than 14) from the battery or alternator to the new relays. After the relays I don't see a problem with 14 gauge wire as the distance from the relays to each window motor is below the 7 foot maximum per the chart linked above. Providing 12 gauge to the relays should provide enough power that both windows can roll up/down. Otherwise you will have the situation when you do both windows at the same time that they slow down. If you do use 12 gauge wire, I highly recommend wiring it directly either from the battery or alternator, the fuse box was not designed to run 12 gauge wire out of the box, introducing a thicker gauge could cause the box to be a hot spot in the wiring.
Also, the Painless setup does not have the original relay, only 4 relays, 1 for each window each direction. So my edit would be the closest to the Painless design.
- Fusible link recommendation.
- No longer use original relay.
My drawing is to demonstrate that the old relay is not necessary. If you go this route, I would recommend tapping the wires directly into the fuse box (see other notes below) rather than hacking up the old relay wiring.
RecapAs far as 4 relays and adding ground wires to the doors are concerned, that is the consensus. Providing power to the relays and to the switches though is what is different. Here's a list of possibilities.
Window motor power:
- From fuse box: Use 14 gauge wire as factory intended (plugged into a BAT port in fuse box).
- From the battery: use heavier gauge wire to take advantage of direct current from battery.
- From the alternator: use heavier gauge wire to take advantage of current from the alternator and include a fusable link to protect the system from damage.
Power to window switches to turn relays on/off:
- Old single relay remains: This relay will simply not allow power to go to the switches unless the key is in the "on" position.
- Old single relay removed, using pink wire to switches: Wired as pictured to the pink wire, the switches will not see power unless the key is in the "on" position.
- Old single relay removed, using orange with black stripe wire: The switches will see power whether key is in the ignition or not (NOT RECOMMENDED).
- No need to worry about if you plug your switch power directly into the fuse box using a free IGN/ACC port.
Other notesFrom this specific posting 78ta included a picture (linked below) of the fuse box with the power window motor power, power window relay power, and power door lock power. (reference:
http://www.78ta.com/HTAF/index.php?topic=8202.msg86153#msg86153)
My ThoughtsI'm just trying to clear up the confusion since there are many ways to power the windows, I believe this outline lists the differences and a reader can decide on their own which is best for their ride.
I'm not completely sold yet on connecting the power to the alternator, but that's what the factory would most likely do. When I get the motor installed I will wire my windows that way with a fusible link and report back if that way works better or not.
I think if the factory used today's standards, they would have the 4 relays wired with 14 gauge wire to the fuse box. If the power windows were added by a professional shop, I think the 12 gauge between the battery to the relays would be used so the windows would have plenty of power to both work as fast at the same time.
