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Discussion Starter #1
Ok so I have been working on installing a 4 channel amp, 4 speakers, new deck into my 98 Jeep Grand Cherokee and I'm running into some problems.

I have a brand new kenwood deck installed X-395, I grounded it using the black ground cable that was behind the radio. I then routed a 6 channel RCA cable and a 9 conductor speed wire from the dash back to a brand new Alpine 4 channel amp in the rear. If you aren't familiar with speed wire its basically one bundled wire with 9 wires inside making it easy to run. On the kenwood harness I capped off the solid blue cable, and the blue/white I have used as my remote turn on(I don't have a power antenna), other than that just red and yellow 12v lines are hooked up. The speedwire is connected to my OEM speaker wiring via Metra harness and ran to the back to the amp.

Alpine amp is powered by 8 gauge fused wire straight to battery, I sanded down to metal around the driver rear seat bolt and used 8 gauge ground wire to ground it.

I hooked it all up, it sounds great, I start the car, it sounds great, THEN I decided I needed to use my headlights, click on parking lights, BUZZZZZZZZZZ, turn them off, silent, click on headlights, BUZZZZZZ, coming from JUST the passenger front door speaker.

This is what I can tell you I've done, it doesn't matter if radio is on/off, truck is on/off, RCA's disconnected from amp, power disconnected from amp, if the headlights/parking lights are on that speaker emits a loud buzz.

Troubleshooting:
-If I hook that amp channel up to any other speaker there is no buzz, likewise if I take that front speaker and move it to another channel on the amp, there is buzz, so it follows the speaker.
-I tried a different speaker obviously to rule the speaker out, same buzz
-If I cut the tie between speedwire and OEM wiring and hook speaker up to speedwire direct from amp, no buzz, so I think my speed wire is good and its on opposite side of truck than my power cables as recommended, as well as my RCA's.
-If I hook the speaker up to the OEM wiring at the harness, no buzz
-If I connect the speedwire to the OEM wire and touch the speaker to the respective splice, buzz
-If I disconnect power, RCA's, remote hook up, and just leave the AMP grounded with that speaker hooked up, it will buzz, but again no other speaker has an issue off the amp and another speaker on the same channel won't buzz. IF I remove the ground from the amp, the buzz goes away.

So that is where I'm confused, that my amp ground is somehow causing this only when the speaker is hooked up to the OEM wiring AND the speedwire, only for that one speaker, because somewhere the OEM wiring is grounded out on something but ONLY when the headlights are on, but that same OEM wiring at the harness with no amp hooked up, doesn't buzz.

Being that it works fine until I tie it into OEM wiring, I feel like its the OEM wiring to that door causing the problem, but still I think its wierd that it works fine until the headlights come on but I digress and I was going to rewire the door, but its a huge pain in the neck due to the molex connectors they use in the doors so I thought I would ask for any advice before I go through that hassle.

Any help or tips or troubleshooting would help and I can be sure to post back results.
 

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pretty good troubleshooting so far. If you remove the speaker from the door does the buzz go away? you can keep it connected, but don't mount the speaker. If it goes away, try another speaker there. Might be a bad speaker and grounding out to the frame and you're grounding it to the door which in turn grounds your amp. fun right?
 

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Discussion Starter #3
Thanks for the reply, if I remove the speaker from the door it still buzzes, if I try a new speaker in the door still buzzes, thats what got me moving up stream to where I pulled my deck, exposed that channels wires and started testing right off the harness and the speed wire. I checked the wiring in the molex/rubber boot of the door and it isn't torn or exposed, and its one solid run from the body side of the molex to the harness behind the radio with no access, I was going to attempt to try to snip them off where they enter the body in my kick panel and see if I can skip having to rewire the door and just extend those to the amp, but I didn't want to touch the OEM wiring without asking you guys if I have missed something obvious or come to the wrong conclusion

Edit:
Also since the 12v turn on is one of the speed wires, I of course disconnected that from the amp and headunit to eliminate it being the cause of the buzz, no change there.
 

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it sounds like you know exactly what it is. Running a new wire will fix it for sure. at least it sounds that way.
 

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Discussion Starter #5
Ok cool, thanks for the replies, I think I can dremel a little bit around the door connector and run a new line through it and the boot still cover it, hopefully so because it is a pain in the butt to manipulate anything in the door jamb area, so much for a painless install I was hoping for, lol but it sounds great just as long as I don't need to drive at night :)
 

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Discussion Starter #6
As I was thinking about this, there is one other thing I'm going to look at, I ran my RCA's and the speedwire on the passenger side of the truck, I tucked it into a track along the rails, well at the beginning of the rail and kick panel is the main fuse box, which is on the passenger side, so the speedwire is below the fuse box, the OEM wiring goes through a hole in the body above the fuse box, I wonder if this close proximity of both wires to fuse box manifests as only affecting that speaker and not the others.

I am going to pull the speedwire away from the fuse box area and test, though I'm not totally hopeful since the RCA's are over there and the spare set from the 6 channel is going to my sub amp that is having no problems with noise, and the 4 channel amp has no problem with noise either until the headlights are on regardless if the truck is on, so maybe something for the headlights draws alot of power from the fuse box, we will see.

These Grand Cherokees have a really wierd headlight system where its not on a relay its the knob, wiring, headlights, which is known to cause very poor output due to how its setup, alot of folks put in an HID style relay harness on the stock stuff just to bypass that, I have a spare one, perhaps that will be another idea as well.
 

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Discussion Starter #7
ok I did some more testing and this is really weird, Alpine 4 channel amp, if I move this speaker to Channel 1 no buzz, Channel 2 buzz, Channel 3 no buzz, channel 4 buzz. On my Kicker 2 channel subwoofer amp, if I put it on Channel 1 no buzz, channel 2 buzz

This is driving me nuts. Anyone have any other ideas or seen something like this before?
 

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Have you checked the fader/balance on the head unit to make sure you have not crossed speaker wires somewhere? On my recent install, the OEM wiring diagram for my car was not correct and when hooked up according the the diagram, I had L+ and R- on one side and visa-versa on the other. Needless to say you get sound, but cannot isolate one speaker at a time.

I would start by checking the ground to your headlight harness in the front of the vehicle first, it's normally toward the top of the front radiator support and has a habit of getting corroded.
 

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Discussion Starter #9
On your advice I decided to hook the deck back up, so I cut all the wires and rewired the deck to bypass the amp and everything to where the deck is running all 4 speakers. I double checked even triple checked I had matched the right colors together.. turn on my deck "Protect"

So I start cutting the speakers until I figure out that its the speaker wire that has been in question the entire time that is causing it to be in Protect.

I pull out my multimeter and connect probes to the door harness, 0 ohms, ok so far so good, so I go short that connection and touch the + and _ together and I get varying amounts of ohms, 3 or so.. which should mean thats a good wire right? I turn on my headlights and no change still reading ohms, and still 0L if I'm not touching them together.

That is where I'm at, still a bad oem wire?
 

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I pull out my multimeter and connect probes to the door harness, 0 ohms, ok so far so good, so I go short that connection and touch the + and _ together and I get varying amounts of ohms, 3 or so.. which should mean thats a good wire right? I turn on my headlights and no change still reading ohms, and still 0L if I'm not touching them together.
I don't understand what you are trying to say here, please explain with better detail.

Which part of the door harness are you checking (inside/outside or TOO/FROM) and what part did you "short" that has varying OHMS?

Does a new piece of speaker wire from the door speaker to the deck fix the issue?
 

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Discussion Starter #12
I hooked the multi meter probes up to the + and - plug where the speaker would plug-in at the door, went to the harness cut the metra harness, in my case the wire is grey / grey.black, so with just the probes in it reads open, like it should. Then to test for continuity I have always been told you "short" the wires so I touched the grey to grey/black with probes still in the plug in and I get varying ohms, which I thought meant that the wire is good? Remember that I also said the noise only occurs when the headlights are on, so I duplicated the test with the headlights on, again same results open when not shorted, varying ohms when shorted. But that wire puts my head unit into protect, and yeah bypassing the wire does work, I just found it strange that it "seemed" to read ok. The problem with running a new wire is that I have molex style door harness and the passenger kick panel is also the side where the fuse box is making it the most difficult fish job of any corner of the jeep so I was trying to avoid it if possible, but sounds like i'm stuck.


Thanks for that video link, but I have checked the boot area, no torn wires..yet..but I know its common, in fact I've fixed a power window wire on the other door like the video.
 

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I get varying ohms, which I thought meant that the wire is good?
NOPE...

You should get a constant value, and it should read almost a perfect zero, but sometimes resistance in the wire will show a .01 but nothing higher.


Hook your meter to one connection at the door where the speaker plugs in, then check for continuity at the other side of the wire where the metra harness gets connected, your meter should read zero, if it does not, you found the bad wire. It will probably be both sides.

Is there any other place in the boot that you can slide a new wire through?
It does not have to follow the same path, nor do you have to remove the bad wire, just bypass it and call it a day.

Also, if there are 2 sides of a molex plug that you can unplug, it may just be full of water which will cause the short you are having. if you find water, blow it out with some air and apply some di-electric tune up grease to both sides of the plug and then retest with your meter.
 
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