Rap How-to On Nbs (keyed Accessory Power)

cgalford · July 30, 2011

I'm looking to add a female 12v accessory plug (cig lighter type) to my truck exclusively for my Garmin GPS, do I have to go the complete relay route or can I just tap pin 2 for the 15amp of power and ground it to the body (or pin 1)?

I appreciate the write-up and input.

You could just go to pin 2 without a relay but then you'd still have constant power and would have to remember to turn on and off the garmin. Pin 7 is Run/Crank feed at 10 amps.

If you don't want to deal with it I sell a pre-made plug-and-play harness with a cigarette plug for $34.99 shipped that take 30 seconds to install. PM me if you'd like more details.

Ranger0001 · September 3, 2011

The question of where to locate RAP (Retained Accessory Power) on the NBS trucks seems to come up often so I thought I would post this info for everybody.
RAP is available to us in the MBEC (Mid-Bussed Electrical Connector) located behind the instrument panel to the left of the brake pedal. The MBEC has 10 positions and the one we are going to us is X14. The problem is that RAP here is limited to only 300 milliamps but there are two other battery feeds in the location as well, one is 15 amps and the other 30. So to use the RAP power for anything but the smallest loads is going to require a relay.

Here are the parts you are going to need and the source that I purchased them from but they are available from many other sources as well.

3 Female GT 280 terminals Delphi Part number 15304711 Mouser part number 829-15304711

1 Relay pigtail Parts express part number 330-075

1 Bosch style relay Parts express part# 330-079

1 GM Connector 20791502 (optional)

Here is the relay harness, relay and connectors.

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There are 5 wires in the harness connected as follows.

White wire – Relay trigger positive – relay pin 85

Black wire – Relay trigger ground – relay pin 86

Blue – Constant 12v source – relay pin 30

Yellow – NO (normally open) circuit – relay pin 87

Red – relay pin 87a, this wire is not used and needs to be removed.

You will need to install the female terminals on the white, black and blue wires. Since I elected not to spend money for the GM Connector I went ahead and covered my connectors with shrink wrap. I may still pickup the connector but needed to get this done and hadn't had a chance to get to the dealer and didn't want to pay GMPartsDirect their freight charges. Here are my finished cable ends.

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Remove the cover to the MBEC, it looks like this

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Here is a diagram of the MBEC connectors; we need to use X14

A close-up of X14

The connections will be as follows

White wire to Pin 8 - RAP feed

Black wire to Pin 1 - Ground

Blue wire to Pin 2 or Pin 5. Pin 2 has 15 amps which was plenty for my needs. Pin 5 has 30 amps. - Battery feed

The remaining yellow wire will feed your accessories.

Enjoy….

Great post, I have only one problem with it. My truck is the 2007 Sieera GMT800. Can I do the same thing with my truck? I am trying to install an XM radio to the RAP circuitry. I've had my dash apart no less than 3 times looking for a place to tap into. I am currently using an accessory power connection, so when I turn off the key I lose power to th eXM radio and get a lot of static. Any help would be appreciated.

I read other post suggesting I use the sun roof power (no luck finding this), or tapping into the radio amp (haven't looked for that one yet).

Thanks, Mike

TmanOKC · October 22, 2011

Hi guys,

Im new to the forum and signed up to post a thank you to the OP for this thread.

I installed the relay and relay harness from parts express and the connectors from mouser ( i ordered 10) along with an ATM fuse holder on the yellow (or orange wire) to send remote turn-on power to my amp.

Eventually i will hardwire up my (near rearview mirror mounted) garmin gps and when i do i will run an extra set of wires up the pillar to hardwire a radar detector plug to the RAP power.

Great forum so far. Just got my 2011 Silverado 1500 Ext Cab with the 5.3L w/ 6spd (Regional Chrome Pkg with 20" Wheels).

Thanks,

TmanOKC

delallen · October 23, 2011

I did this mod a few weeks back and want to say "Thank You" to the the OP. Very detailed instructions and parts list.

jcolson · April 21, 2012

Diesail - thanks a LOT for this post ... I didn't use the same parts, but this post made it extremely easy to hookup my sirius stiletto2 in my silverado.

cujo8 · April 26, 2012

I'm just getting around to installing the RAP relay and associated wiring. I did check the GM Upfitter Site to check on another connector and discovered this Tech Bulletin covering added relays to the electrical system. I'm sure no one wants to void the warranty on any of the computers or control modules in their truck. Adding a 1N4003 diode across the windings of the relay will keep induced voltage spikes generated by the relay when it drops out might save you some hard earned $$$$.

Just a word to the wise. Read the Tech Bulletin.

Ted

I read the tech bulletin you linked to and it say's:

"This bulletin documents the recommended practice of installing of a diode to Aftermarket

Solenoids/Relays to Suppress Voltage Spikes (this is in the event Non-Automotive Grade

relay or solenoid has been used). This diode installation eliminates potential excessive

voltage spike."

so it looks like you only need to add the diode if you use a non-automotive grade relay. Is the Bosch 12VDC 5-pin relay SPDT 30/40A p/n-330-079 listed in OP an automotive grade relay? I'm thinking that it is an automotive grade relay and the diode addition would not be needed in this case, correct?

Thanks.

jsilerjr · April 26, 2012

Great Post .... I used to it power my two 7" LCD Headrest Monitors. It was easy and fast withe instructions you gave.. now I have have RAP power to the video system. Thanks

JS

jsilerjr · April 26, 2012

here is the product description from parts express, I would say , from reading this, it is automotive grade and a diode would not be needed ..

12 VDC Tyco 5-Pin Relay SPDT 20/30A (Formerly Bosch)

12V, 30A relay popular in automotive sound and security installations. Plastic housing with mounting tab. Tyco Electronics has acquired the automotive relay business of Robert Bosch GmbH and is now manufacturing this relay to the original Bosch specifications. SPDT, 20/30A. Equivalent to Bosch #0 332 209 150. Mfg. #V23234-A1001-X036. Made in Portugal.

Edited April 26, 2012 by jsilerjr

jsilerjr · April 26, 2012

I'm just getting around to installing the RAP relay and associated wiring. I did check the GM Upfitter Site to check on another connector and discovered this Tech Bulletin covering added relays to the electrical system. I'm sure no one wants to void the warranty on any of the computers or control modules in their truck. Adding a 1N4003 diode across the windings of the relay will keep induced voltage spikes generated by the relay when it drops out might save you some hard earned $$$$.

Just a word to the wise. Read the Tech Bulletin.

Ted

I read the tech bulletin you linked to and it say's:

"This bulletin documents the recommended practice of installing of a diode to Aftermarket

Solenoids/Relays to Suppress Voltage Spikes (this is in the event Non-Automotive Grade

relay or solenoid has been used). This diode installation eliminates potential excessive

voltage spike."

so it looks like you only need to add the diode if you use a non-automotive grade relay. Is the Bosch 12VDC 5-pin relay SPDT 30/40A p/n-330-079 listed in OP an automotive grade relay? I'm thinking that it is an automotive grade relay and the diode addition would not be needed in this case, correct?

Thanks.

Edited April 26, 2012 by jsilerjr

cujo8 · May 4, 2012

here is the product description from parts express, I would say , from reading this, it is automotive grade and a diode would not be needed ..

12 VDC Tyco 5-Pin Relay SPDT 20/30A (Formerly Bosch)

12V, 30A relay popular in automotive sound and security installations. Plastic housing with mounting tab. Tyco Electronics has acquired the automotive relay business of Robert Bosch GmbH and is now manufacturing this relay to the original Bosch specifications. SPDT, 20/30A. Equivalent to Bosch #0 332 209 150. Mfg. #V23234-A1001-X036. Made in Portugal.

I ordered and received my 12VDC automotive 5-pin relay SPDT 30/40A (p/n-330-079) and relay harness (p/n-330-075) from Parts Express and this relay/harness doesn't have diode protection. Just to be safe, I added a 3amp, 400PIV diode to the harness between white(85) and black(86) pigtail wires just behind the black socket to give the diode protection to this relay assembly (Diode stripe-end connector should be attach to the white #85. connector). The diode can be purchased for less than $2 from Radio Shack.

cujo8 · May 7, 2012

First off I want to thank the OP (Diesail) for the great write up on this topic. I basically followed his directions, but added diode protection to the relay harness just to be on the safe side. I now have switched 12V power for my on-board air compressor for my Air-Lift helper spring system. Thanks Diesail.

cujo8

stewart7225 · May 12, 2012

So how are you guys adding the diode protection in here? does anyone have a picture or a better description? I just finished installing this to run some LED lights and it worked perfectly!! Thanks to the OP for the great writeup.

cujo8 · May 13, 2012

My original directions posted above were:

I added a 3amp, 400PIV diode to the harness between white(85) and black(86) pigtail wires just behind the black socket to give the diode protection to this relay assembly (Diode stripe-end connector should be attach to the white #85. connector).

To add the diode to the harness, I used a small jewellers flat blade screw driver to pop out the white and black female spade connectors from the black 5-pin relay connector. I bent the diode leeds so that it matched the spread distance of the white and black connectors when they were in the 5-pin connector. I cut the diode connector leeds down a little. so the diode would just stand ~ 3/16 off the back side of the 5-pin connector where the wires exit the connector. I then soldered the diode leads to the brass wire crimp ends of the white and black female spade connectors on the inside edge. The orientation of the diode is important, so follow the directions in the previous paragraph. Then insert the white and black female connectors back into the 5-pin connector exactly as they came out, so that the white wire connects to the #85 connector on the diode.

jgriffin187 · June 11, 2012

I'm trying to hardwire my Garmin GPS and I'm hoping that someone can give me a little help on this one. I have all of the parts in the list above (including GM connector). I plugged everything in and the GPS powered up as expected when I turned the key. I disconnected the GPS and was running the wires where I wanted them (out of site) and as I was doing this the yellow wire hit a bolt under the dash and shot a quick spark (didn't realize that I still had the key on). Anyway, the GPS doesn't power on now, so I'm assuming that I blew a fuse somewhere? I checked the MBEC fuse under the hood and it looks ok. Any ideas?

Thanks,

Josh

Bill in Niantic · July 15, 2012

My original directions posted above were:

I added a 3amp, 400PIV diode to the harness between white(85) and black(86) pigtail wires just behind the black socket to give the diode protection to this relay assembly (Diode stripe-end connector should be attach to the white #85. connector).

To add the diode to the harness, I used a small jewellers flat blade screw driver to pop out the white and black female spade connectors from the black 5-pin relay connector. I bent the diode leeds so that it matched the spread distance of the white and black connectors when they were in the 5-pin connector. I cut the diode connector leeds down a little. so the diode would just stand ~ 3/16 off the back side of the 5-pin connector where the wires exit the connector. I then soldered the diode leads to the brass wire crimp ends of the white and black female spade connectors on the inside edge. The orientation of the diode is important, so follow the directions in the previous paragraph. Then insert the white and black female connectors back into the 5-pin connector exactly as they came out, so that the white wire connects to the #85 connector on the diode.

I have been using this setup since 5/10 with no problems, and with no diode. So the automotive relay seems to work just fine.