A Real Rap Module With 2 Rap Power Connections

DofD · August 10, 2009

Last year when I began planning for the the upgrades to my Tahoe (speakers, amps, sub woofer, video headrests, radar detector) my research turned up that there was no true RAP or accessory power connections available on the GMT900's. Reading through the electrical manual for the the GMT900's (for 08 model year) there was a diagram for a RAP module, but it wasn't implemented. It is true that there are lines that 12V and could provide RAP power, but these lines where typically part the GMLAN or other subsystems. I didn't want to (1) piggyback off another system where I could run into current limitations, and (2) use the GMLAN lines as a power source for accessories. Basically I didn't want to mess with and possibly cause issues with other systems. Further reading in the GMT900 electrical manual showed that there was an unused connector (X14) in the left side (under driver's side dash) junction panel that provided +12v battery, accessory voltage, and ground. Sounded like a good place to connect a RAP module.

Since we weren't going away for our summer vacation this year (which was last week to coincide with the wife's birthday) it seemed like a good time to build the module and perform the other upgrades on the truck (to be covered in a different thread). I didn't count on getting nasty ass sick though, which has put me way behind schedule on the installs (truck interior is still in pieces in the garage).

So... For the prototype of the RAP module here is what I needed.

Main Tools

- Soldering iron

- Utility knife

- Wire strippers

- Crimpers

- Rotary tool (Dremel): for making the mounting holes in the module box

- Hot glue gun

Supplies

- 18 gauge yellow wire

- 16 gauge red wire

- 16 gauge black wire

- 16 gauge blue wire

- 16 gauge green wire

- Project box

- 3 wire connector

- 6 wire connector

- 2 x standard 12v relay

- 4 x fuse holder

- Shrink tubing

- Solder

Wiring schematics

Diagram of Left I/P Junction Box

Diagram of X14 connector pinouts

The input connector has 3 lines: red (+12v battery), yellow (RAP control line), and black (ground)

The output connector has 6 lines: 2 x red (+12v battery), 2 x black (ground), blue (+12v RAP accessory power), and green (+12v RAP accessory power)

Where a blue, black and red makes one RAP bundle, and a green, red and black makes the other RAP bundle.

I used the Dremel tool to make the mounting holes in the project box.

I then mounted the connectors, fuse holders, and relay bases into the project box using the hot blue gun.

For the wiring of the individual connections I just followed the schematics.

After finishing wiring everything up I tested everything thoroughly using a 12v wall adapter to provide the input voltages. It worked perfectly, the output 12v battery had 12v, and the output RAP power lines (blue and green) had 12v only when the input RAP control line (yellow) had power.

Finished unit.

I haven't got this installed into the truck yet as I'm not to that point of the installs yet. But I'll have pictures of it installed when I get to that point.