Car Stereos: RAP Tap - 2000 Buick Lesabre, amp fuse, fuse box

Question
QUESTION: I read in another question that you tapped into the RAP (Retained Accessory Power) in the fuse box location under the back seat.  What is the best way of tapping into that power location?  To go in from the fuse side? or find the wire coming out under the fuse box and tap into that way (certain color of wire or grid location)?  I found the RAP fuse but there seems to be no direct correlation between the front of the fuse box and the backside with the wires coming out.  

I'm trying to wire in a wired FM modulator with ipod/iphone charging capabilities into the RAP.

Thanks!

ANSWER: Hi Aaron,

In the LeSabre, I generally tap into the RAP relay, not the RAP fuse. I don't think the RAP fuse would work for your purpose; it's probably the supply fuse for the relay, so it would carry constant power.  

To tap the relay, I use a ATM fuse tap like this one:

http://ecx.images-amazon.com/images/I/31a-f52lPfL._SL500_AA300_.jpg

If you flatten it out, you can fit it over the terminal of the mini relay and press the relay back into position.  If I recall correctly, the output of the RAP relay is terminal 87.

You should be able to find the RAP output wire along with all the other wires that are bundled together at the fuse/relay box.  I've never looked for the wire, but it should be easy to identify with some time and a multimeter.  My guess is that the wire will be one of the thicker wires, and may be dark green or dark blue.  If you can locate the wire, you can tap this as an alternative to tapping the relay terminal.  Either way, you should put a fuse on your new wire, as close to the tap point as possible--a 3-amp fuse should be sufficient.

Hope this helps!

Brian  

---------- FOLLOW-UP ----------

QUESTION: After asking you my last question I started using the multimeter etc and did find the RAP fuse to be always on...thats when I found the relay, but wasn't sure where to tap exactly, but your answer helped.

I got it... I think :)  It was a medium sized dark blue wire coming out of the middle section grid at A6 behind the fuse box.  I just tapped that line after confirming it with the multimeter.  Is it normal for most car accessories to see 15 volts with the car running? due to the alternator?  

RAP car running = 14.97 volts
RAP car stopped/radio on = 12.70 volts
RAP car stopped/radio off <= 15 mV

Thanks!

Answer
Hi Aaron,

The standard alternator output voltage is 14.4 volts.  Yours does seem to be a little high, but I doubt it's enough too hurt anything.  Try revving the engine a bit and see if the voltage climbs any higher.  If it's going much higher than 15 volts, you might want to have your alternator checked.


Brian