Ignition Wire on AVH-P4300DVD Problem

[izzbo 10+ year member]

I have a new Pioneer AVH-P4300DVD that I'm installing in my Hummer H3. I bought a Metra GMOS-01 so I didn't have to splice into the factory wire harness. I first hooked up the GMOS-01 to the Pioneer's radio harness and just wrapped the wires together and taped them w/electrical tape to ensure everything works before I solder and use the shrink wrap stuff. Everything worked great and I left it in like this for 2 days b/c I was waiting for a video bypass relay to come and didn't want to pull everything out twice. Well the last day the radio would randomly get a mute signal from the car (I needed to attach the mute wire b/c I have onstar and that mutes the radio) so I figured it was loose wires so I took it out and drove a day w/no radio.

Today the bypass came. I hooked that up and soldered all the connections and used the heat shrink for every connection. When I put the radio back in the car the radio is on all the time. I know the red wire is the ignition wire that should turn the radio off. I used a multi-meter to check the connection of the wire and I get a reading (the wiring was not hooked up in the car when I did this, I took it out and I am setting the meter to OHM X1K mode and touching the pins that connect to the red wire on each end of the GMOS-01 and I get a reading) and it seems fine.

My question is could I have messed something up heating the wire during soldering? There is a resistor on that wire. Could I have damaged that which is causing this issue? I didn't have anything plugged into the GMOS-01 or during the soldering though so I didn't over heat the GMOS-01 unit. And my other question is how can I diagnose if it's the radio, my wiring, or the GMOS-01? I put in the stock radio to make sure it wasn't the car and the stock radio behaves as it should. Can I use the multi-meter to see if a current is flowing through the red wire when plugged in? If so should it have nothing when the car is off and power when the car is on? Can I somehow test out the ignition wire manually?

Thanks in advance for the help. I'm just baffled on why it was working before and now isn't? I did see the other thread about a similar issue but I didn't want to hijack their thread.

- Jason

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[dumple 5,000+ posts]

if itst anyhting like my gm the red wire was acc and the yellow was b+

 

[accuab 10+ year member]

You could plug the harness assembly and see if you have voltage through your accessory wire when you turn the key on. Set the mm to dcv and connect the red to that pin and ground the black lead. If you don't see near 12v then something obviously is wrong.

 

[izzbo 10+ year member]

Thanks everyone for your suggestions. I'll try the multimeter w/the red wire and post my results. If anyone else has some suggestions about why this is happening please chime in also. The more info the better for me.

 

[accuab 10+ year member]

Thanks everyone for your suggestions. I'll try the multimeter w/the red wire and post my results. If anyone else has some suggestions about why this is happening please chime in also. The more info the better for me.

This should work as far as I know but I am not completely sure about the onstar retaining harness. But without power with the key on to the acc wire, you will not get the power to turn on the unit. Since it worked when you had everything just twisted and taped, you know the harness is in working order. If you don't get power through the acc wire, check it at the factory wiring then work your way back until you find the culprit. Your factory wires should all be good since you said that you reinstalled the factory unit and everything worked as normal. If there is a fuse, double check that you didn't blow it.

 

[izzbo 10+ year member]

Thanks everyone who replied. accub, I think my issue is opposite what you are thinking. The problem is that the head unit is always on and doesn't turn off when I turn off the car. As I said in my previous posts it was working as it should initially then stopped working when I soldered the connections so the radio is always on.

I checked the connection w/a multimeter sure enough the red ignition wire has 12V going through it when the car is off. Am I correct in thinking that is should have no current when the car is off, right? The yellow wire (the constant 12V( is also powered all the time. The car wiring is good b/c I can remove the GMOS-01 harness and put the sock head unit in and works as it should. My guess is that something happened w/the GMOS-01. The car's stock harness plugs in to that and then the wires on the GMOS-01 connect to the pioneer harness. I don't think it is the wiring I did b/c it is extremely simple. 95% of the wires that I have to connect are the same color and the others are obvious. And since the stock unit works nothing is wrong with the car's wiring. And I imagine the radio works. Since there is constant power via the ignition wire that leave the harness. Is my guess that something is up w/the GMOS-01 correct or does anyone see another possible culprit?

Thanks in advance everyone!

 

[accuab 10+ year member]

Yea I guess I missed that somewhere. You could add a hot wire from the fuse box on a fuse that is only hot when the key is on like you would do for an amp.

 

[izzbo 10+ year member]

I do have an extra Bussman add a fuse lying around that I could use for this but it really irrates me that I can't use the wire on the GMOS-01. The GMOS-01 has all the wires you need to hook up everything right there and it did work at one point. Has anyone every used a GMOS or similar unit and had troubles? It's just sooooo strange that it worked until I soldered the connections. I can't wrap my head around what could have happened. It so simple to hook up a monkey could do it. The GMOSes are actually very cool b/c you can add any aftermarket item w/out touching your stock wiring harness. It makes for a very clean install. And I'm putting all the stock stuff back in when I sell the truck so the cleaner the install the easier it is for me in the long run. Thanks again for all your guys help!

 

[accuab 10+ year member]

I've used plenty of harnesses similar to that one just never one that retained onstar. Maybe you could try to just run a wire from the fuse box and see if that is your problem. I just don't see why it would work fine until your soldering unless you switched the wires somehow but it seems you have checked everything. I would lean more towards that harness since your stock head unit works fine. Did you check the factory wiring(nothing connected to it) and see if both power wires have power all the time. I have read there are a few cars that have to be different because of this similar situation of both being hot all the time and they end up splicing a wire under the column. I'm not familiar with the hummer but I would think it would be like the rest of the gm products.

 

[izzbo 10+ year member]

accuab, thanks for helping me with all my questions. I really appreciate it. What's the best way to test the car's wiring harness wires? Do I have to remove a piece of the insulation or can I stick the probe right into the end of the wiring harness? The reason I ask is b/c I tried that (sticking the probe into the end of the harness where the said wire is connected to) and when I touched it to the car frame I blew the radio fuse so I must've messed something up.

 

[I Like Waffle]

did you buy one of the cheap AVH p4300s off ebay? Theres a seller whos got them for like 300 bucks selling them as new but theyre really used/refurbished. I Bought 5 of them and returned every one.

 

[accuab 10+ year member]

Yea you should be able to probe the pin and ground the meter and see the voltage without blowing a fuse.

 

[izzbo 10+ year member]

No I bought a new one on amazon for $370. It's the GMOS that is having the issues b/c there is definitely power going through the ACC wire at all the time. My new GMOS-01 arrived yesterday so I'm trying the new one out today. I'll update the thread so everyone knows what I find out.

 

[izzbo 10+ year member]

I hooked up my existing wiring to the new GMOS-01 box and it works as it should. So somehow with in 3 days and disconnecting it once the GMOS-01 went to crap. But here is that catch. I bought one of those video parking break bypass relay's pre-made off of ebay. I did this b/c the pre-made one was the same cost as going to radio shack and buying a 12V relay. When I was trouble-shooting my original GMOS-01 I disconnected that from the wiring b/c it was the only new thing I added between when the radio was working and when it wasn't. I didn't reconnect this when I tested out the new GMOS so that is my next step. I can't see how this would damage it (it's simply a 12 V relay w/a ground wire, a wire connected to the radio's parking brake wire, and a wire connected to the amp's remote control wire - when the remote wire gets voltage it trips the relay and the parking break wire gets voltage so the radio thinks we are in park). I'm hooking that back up today so we'll see what happens.

 

[izzbo 10+ year member]

Well I added the video bypass switch and it is working fine. I used the same wiring harness but just plugged it into the new GMOS-01 unit. Thanks everyone for your help with this! This is a great forum and really helpful. I am still having trouble with the mute signal though. This was an issue when I first installed it. I'm going to look through the forum archives to see if I can find a thread w/a similar problem and if not I am going to post a new thread on it. Thanks again everyone!