03 P5 Wiring Issues....ADVICE!!

[zcast]

Ok, so without boring you with a 5 page rant of the problem with my stock HU not being fixed after 5 visits to the dealer, i want to just cut to the chase and get some work done. I've been holding off on installing my Alpine XM system until the Stock HU was fixed....well its not, but the Radio part works (not the cd changer) so I went ahead and installed it tonight.....here are my questions:


All the system consists of is an FM modulator, an XM receiver (not a head unit!), and an Antenna. The FM modulator needs a constant 12v, an ACC (switched Power) and a Ground. The Receiver needs constant 12v and ground. (Antenna needs nada!)

Anyway, so since I need to STAY AWAY from removing the stock HU and tapping into the harness for the wires I need, (since the dealer is still trying to fix it, and they are already giving me grief for knowing I intend to install an XM system), I need to find these wires elsewhere under the front dash. Here is where I came up with some things......please tell me if anything is wrong!


For the receiver, it was easy enough, I stuck the receiver in the trunck/hatch and tapped the 12v power off the factory sub harness. The ground wire wasn't long enough, so I just grounded it to the chasis.

The FM modulator was the hard part. Please understand i was in a rush, so my placement for someof these might not be ideal, but they SEEM to work for now.

First I needed constant 12v, which from talking to Crutchfield (where i bought the stuff) they informed me that that was Blue w/ Red stripe. First, I found this one in a HUGE harness that sits at the passengers feet behind the left kick panel. So I tapped into that one.

Next was the ACC switch (Pink w/ Black Stripe), where I found it coming down from the radio in the taped up bunch, so i stripped the tape off and tapped into that.

For the ground, I didn;t have anything good to tap to, so I threaded it onto a screw that holds a panel piece it. ( I know this is a problem!)

Anyway, so when I powered up, no go on the XM remote (which is powered off the FM modulator), So I moved the ACC tap to another location on the passenger side on a small 2 or 3 wire harness directly behind the glove box.

Powered it up, no go.

So then I moved the 12v constant to a 4 wire harness located directly behind the glove box, a little lower than the ACC tap.

Powered up....Good to Go!

I tested eveything, and all looks fine except......

when the A/C comes on, the display for the remote dims.....i think that is due to poor grounding and i will fix that when I have a better connector to attach to the body.

also, when I manually power the unit down (via the power button) and leave the car On, and then power it back up, it returns to the original station it was on......yet when I turn the car off, and power the unit back on, the unit defaults back to channel 1. Could that mean the constant power isn't tapped correctly, or maybe thats just how the unit works? Will the unit gain all the power it needs to run from the ACC wire, and the constant is for "memory"?

Any help would be appreciated!!

thanks

zcast

 

[Rider69]

Sounds like your constant power is .... not constant! And you definatley need a better ground.

Sorry to hear about all your problems with Classic. When I was doing my HU install, I went up to the one on the trail and asked the service guy to remove the old unit and they did it no questions asked. I have a single disk radio from my stock P5 available if you are interested?

 

[shinzen]

I am a former mecp installer- hope I can help you out a bit. First thing that I would do, if you have a couple of bucks is get a test light from carquest. You tapped into a switched power supply for your remote unit, and you MUST re-ground it- just pull up your carpeting a bit, use a flathead screwdriver to scrape down to bare metal, and check on the other side to be sure you are not hitting anything like a gas line or electrical harness on the other side. For your power situation get the handy dandy test light out, clip the alligator clip to a good ground source and probe carefully into wires to find a constant power source- there are two important things about this- do NOT PROBE ANYTHING WRAPPED IN YELLOW! That is your airbag system and you probe it and you could set it off and have to get it reset by Mazda. Second, when you find your power source, check it at every point of your ignition being off, acc, on, and start- sometimes when you think you've found a good one, it will actually go out when you turn the key to start which could be why you are having that remote reset on you. Hope that helps

 

[zcast]

i was looking for a "sniffer" or test probe, but couldn't find a decent one.....i have a decent multimeter, i will go check and see if that will work. Anyway, what do you find is the best way to ground to the chasis? I mean, i got a bare end (stripped wire) that I need to "attatch" to the body somewhere. I understand about stripping the paint and all, but ATTACHING it, what would you use. In past, I always tried to find a screw or something that went into the body frame, but where I am installing this, i cannot find anything accessible. So i need to ATTACH it to the body somewhere. The GROUND wire in the harness isn't very accessible, but the chasis is, so should i screw something into it, or what? Eventually, I will dress it up a little nicer in the back, but up front, it just need to get tapped in correctly.

zcast

 

[Ballard]

By my limited experience and other's comments, your display will always dim momentarily when the A/C comes on, your windows are operating...etc. That's just the way it is. Sorry.

 

[shinzen]

use a small self tapping bare metal screw, and make sure you use a connnector of some kind, a multimeter will definitely do the trick, and do NOT use the ground in the harness- the wiring in all cars, especially the mazda's is not great, and the ground in the harness is the first thing that I would avoid. The self tapping screws have what looks like a very small drill bit on the end of them, made to screw into metal- I would recommend not using a painted or black screw- it won't be as good of a contact.

shinzen