Lost reception on radio

[emti309]

So a few months back without warning my radio lost reception on all stations except the very local stations and a strong signal from 30 miles away. Now if I drive into the big city of Columbus, Ohio I get all my stations back but as soon as I leave my stations disappear into static. So my question is is this a radio problem or an antenna problem. Also been having problems with the 6 disc CD changer not wanting to play CD's keeps saying check disc. Please Help.

 

[The_Roadie]

97% chance it's the antenna. 3% chance my statistics are wrong.

Disk issues are often dirt on the mechanics. Get a CD cleaning disk that has a little brush embedded in it. Or blow in some compressed air. Or disassemble the entire unit for a thorough cleaning. (much more annoying work).

But I'm not the audio guy. They should be arriving soon.

 

[emti309]

Thanks Roadie I should have mentioned that I have used canned air and I have also taken the raio out of the dash and reconnected everything at least I think I have.

 

[BRomanJr]

Thanks Roadie I should have mentioned that I have used canned air and I have also taken the radio out of the dash and reconnected everything at least I think I have.

Since you have had it out, I would suspect the antenna connection did not "snap" back in properly and fell out causing your reception issue.

If this started before you took it out, (thought you may have taken it out for the disc problem) the wire could be damaged, It's unlikely that the antenna went bad.

 

[The_Roadie]

I had a Civic antenna coax damaged at the bottom of the antenna above the driver's feet, and replugging and inspecting at the radio end was no help.

 

[emti309]

I did take the radio out after I lost reception. Now my question if anyone knows is the antenna plug a plastic snap in or a metal connection? Because I don't remember taking off and putting back any metal connections. Also I was having a serious vibration problem at the time which later turned out to be the drive shaft. I found this out when it snapped.

 

[Envoy_04]

I did take the radio out after I lost reception. Now my question if anyone knows is the antenna plug a plastic snap in or a metal connection? Because I don't remember taking off and putting back any metal connections. Also I was having a serious vibration problem at the time which later turned out to be the drive shaft. I found this out when it snapped.

Should be a metal connection (looks like an oversized headphone plug). Pull the radio again and make sure the coax is actually plugged into the radio, if you didn't hook the antenna back up then that could definitely be your issue, and the coax is hanging out in the dash somewhere if you forgot to hook it back up.

 

[emti309]

Is it possible it vibrated out?

 

[Envoy_04]

Is it possible it vibrated out?

The one on mine snapped in place pretty firmly, but it's very possible that it vibrated out maybe if it wasn't plugged in all the way. Definitely worth checking it out.

 

[emti309]

OK so update went out took it out of dash again antenna wire firmly in place removed it checked for corrosion none place firmly back into it's home checked all other connections started vehicle still sh**y signal dunno what to do at this point I need a radio I dont want to buy a aftermarket if it is an antenna problem and if its an antenna problem would rather just fix it mind you who don't know the ends of the antenna on my vehicle are in the back side glass.

 

[The_Roadie]

Long run of coax from the front to the rear glass. Did you inspect the whole length?

Have you tried sticking a wire coat hanger in the back of the HU?

View attachment 33897

 

[emti309]

I am not sure where the coax runs to inspect it or I would any info would be greatly appreciated.

 

[The_Roadie]

I have the later cowl antenna. You could always add one of those.

Or: Just start at the destination end of the coax. Surely you can see it there? Remove interior panels as needed to follow it back to the source. I don't know if it goes up to the headliner or down to the door sills, but those are about the only two ways to use the cabin to get from the front to the back. It's an exploration project - most folks don't know where things go when they start out. You could take pics and be the first to document it!

 

[emti309]

I could do that since the antenna is in the back glass on both sides I guess I just need to pick a side.

 

[Texan]

Some of the older cars had a cell phone/on star antenna in the rear. Don't know if
it was used for radio. The antenna plug on the radio was known as a RCA jack.

 

[emti309]

Yeah I have the OnStar antenna on the glass but the actual radio antenna is built into the back side glass on both sides

 

[mrwitty_1]

Drop the glove compartment door down and look behind it, my 2002 Envoy has an antenna connection behind there, also can be seen by removing the left end dash cover. Just a thought. Good Luck

 

[emti309]

Drop the glove compartment door down and look behind it, my 2002 Envoy has an antenna connection behind there, also can be seen by removing the left end dash cover. Just a thought. Good Luck

I did this saw the antenna wire no connection though can you take a picture so I know what I am looking for.

 

[emti309]

ok so I did some looking at the two back glass and one has like 6 wires running trough it while the other only has 2 does anyone know where I should start.

 

[The_Roadie]

Antennas are coax while the multiple conductor one (on the passenger side?) is regular wires. You need only bother tracing coax.

 

[BRomanJr]

ok so I did some looking at the two back glass and one has like 6 wires running trough it while the other only has 2 does anyone know where I should start.

Glass Antennas can be passive or amplified, because you see it on both sides there is probably a multiplexer/amplifier hidden somewhere (I'll guess C pillar on passenger side, and the wires run in the headliner). Have you checked fuses? it could be on some obscurely named fuse, may need to check the wiring diagram to find its location, name and number, and most importantly, if it exists.

 

[emti309]

I have checked everything but the fuses as u said the antenna runs through the headliner. So if anyone has a fuse diagram and location as to which fuse box it would be greatly appreciated. If this doesn't work I think I will be trying an aftermarket radio.

 

[The_Roadie]

I don't have a 2002, so my factory shop manual is useless to you. Never heard of a 2002 having an amp needing power, but I don't know it all. Check in here: http://gmtnation.com/f23/need-service-manuals-get-them-here-371/

In 2004, the antenna is a whip on the cowl. Guaranteed passive. I highly recommend buying a cheap cowl antenna and testing your head unit with that. Or stick in a coat hanger as was previously suggested.

An aftermarket radio won't be a rock-bottom cheap diagnostic technique, since you'll also have to do the research here or at your vendor and buy an adapter, or else your radio power will be under full manual control and won't shut off automatically.

 

[emti309]

TY Roadie somewhere along the line I missed the coat hanger in the back of the HU. As soon as I find a metal coat hanger I will do this.

 

[emti309]

Ok went and took radio out of dash again and disconnected antenna. Place metal fly swatter what I could find and guess what nothing but what I have been getting. So does this mean its the head unit? Also unfortunately the fuse diagram was useless as it was not relevant to my model year there must have been some changes.

View attachment 34017

 

[BRomanJr]

Ok went and took radio out of dash again and disconnected antenna. Place metal fly swatter what I could find and guess what nothing but what I have been getting. So does this mean its the head unit? Also unfortunately the fuse diagram was useless as it was not relevant to my model year there must have been some changes.

View attachment 21652

Make sure "fly swatter" does not touch the case of the headunit or anything but the inside terminal of the antenna socket. (looks like it is touching the case?)

 

[emti309]

I tried several different ways and yes sometimes it was touching and other times it wasn't I was experimenting.

 

[Mark20]

Do you have some sort of FM transmitter for sending audio from a MP3 player or such to a radio? You can verify its working with a known good radio and then place it right by the headunit. Antenna or not if the transmitter is right next to it, the headunit will receive some signal. If nothing, then I'm afraid to say its probably dead but not necessarily un-repairable.

 

[emti309]

Unfortunately I don't but my sister has a spare radio from a car she used to have I am going to get the installation parts for it I have a friend who will put it in for me and hopefully I will get my radio back

 

[jsheahawk]

Ok went and took radio out of dash again and disconnected antenna. Place metal fly swatter what I could find and guess what nothing but what I have been getting. So does this mean its the head unit? Also unfortunately the fuse diagram was useless as it was not relevant to my model year there must have been some changes.

View attachment 21652

It's a silly question, but is that fly swatter coated in plastic?

I tried several different ways and yes sometimes it was touching and other times it wasn't I was experimenting.

Ahhh...college.

Jared

 

[Mark20]

Even if it was, when you get it close enough to the center pin of the radio antenna port it will couple some signal in.

 

[emti309]

No actually it was painted but I removed the paint to make sure I was making good contact.

 

[Bill05EnvoySLT]

No actually it was painted but I removed the paint to make sure I was making good contact.

IIRC , you said it pulled in strong signals? the rest are what fuzzy? seem to go in and out?

If you really wanted to test the head unit, i would suggest using an aftermarket antenna plugged directly into the back of the factory head.. and if that works then you know its the factory Antenna system in trouble. if not then the head unit is defective. it happens.. I cant see the aftermarket antenna being much..

Metra Electronics Stock/ANTENNAWorks universal 14 in. removable black conductive rubber mast side/roof mount antenna for 1 in. hole split ball 54 in. cable (AW-US03R) | Antenna | AutoZone.com

This may be an option since its 10.00 and may even be able to return it if it doesn't work..

 

[coolasice]

View attachment 34039

look here. http://parts.nalleygmc.com/showAssembly.aspx?ukey_assembly=437265&ukey_product=2804491

schematic:
View attachment 34040


There is also a service bulletin for this... 05-08-44-016a
http://www.google.com/url?sa=t&rct=...=ioHBa5TCsE0GXpdp4wZO1Q&bvm=bv.64367178,d.cWc

 

[coolasice]

This might help too:


Diversity Antenna System
Description and Operation

This diversity antenna system is comprised of 3 glass mounted antennas, a radio antenna module, and an FM impedance matching module (Radio Antenna Buffer). The primary AM and FM antennas are an integral part of the right rear quarter glass and are connected to the radio antenna module. The secondary FM antenna is an integral part of the left rear quarter glass and is connected to the FM impedance matching module. The radio antenna module processes the antenna reception signals and phase aligns them to create one strong signal. The FM impedance matching module boosts the secondary antenna signal and transmits it to the radio antenna module.

The following information lists the most probable cause of the concern to the least probable cause followed by the appropriate test for that condition. If the test leads to the replacement of a component, always inspect for a poor connection before proceeding with the replacement. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Important: Perform the Antenna System Test and test the antenna coax cable prior to performing any of the following tests. Total resistance from end to end of center conductor should be 0.20 Ω or less.

Poor Reception on Both AM and FM Bands

The radio antenna module is not grounded properly. The module grounding screws should be clean and tight. The antenna module ground is either a chassis ground or a ground strap. Measure the resistance from the antenna module base plate to a good ground. Resistance should be 0.20 Ω or less. Find and correct the condition if the resistance is out of specification.
The antenna enable signal is not present at the radio antenna module. This could be caused by an output failure of the radio or an open/shorted antenna enable signal circuit. In order to test the antenna enable signal circuit, the radio must be ON and tuned to the FM band. Disconnect the radio antenna module. Measure the voltage from the antenna enable signal circuit of the radio antenna module to a good ground. Voltage measured should be near B+. If the specified voltage is measured, test the antenna enable signal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. If no failures were found, replace the radio. Refer to Radio Replacement for service procedure.
The FM composite signal circuit to the radio antenna module is open or shorted to ground. Test the FM composite signal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.
The feed coax at the radio antenna module has been inadvertently swapped with the FM impedance matching module crossover coax. Ensure that the feed coax, marked with a yellow band, is in the correct socket on the radio antenna.
Improper retention of the antenna cable in the floating retainer. Poor or no connection with the radio will result when the radio is installed if the antenna cable is not properly attached in the floating retainer. Inspect the antenna cable for movement in the floating retainer. Replace the antenna cable if movement is found.
Defective radio antenna module. Replace the radio antenna module. Refer to Radio Antenna Module Replacement for service procedure.

Poor Reception on AM Band Only

Defective AM antenna.
Defective radio antenna module. Replace the radio antenna module. Refer to Radio Antenna Module Replacement for service procedure.
The antenna enable signal is not present at the radio antenna module. This could be caused by an output failure of the radio or an open/shorted antenna enable signal circuit. In order to test the antenna enable signal circuit, the radio must be ON and tuned to the FM band. Disconnect the radio antenna module. Measure the voltage from the antenna enable signal circuit of the radio antenna module to a good ground. Voltage measured should be near B+. If the specified voltage is measured, test the antenna enable signal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. If no failures were found, replace the radio. Refer to Radio Replacement for service procedure.

Poor Reception on FM Band Only

Defective primary or secondary FM antenna
The antenna enable signal is not present at the radio antenna module. This could be caused by an output failure of the radio or an open/shorted antenna enable signal circuit. In order to test the antenna enable signal circuit, the radio must be ON and tuned to the FM band. Disconnect the radio antenna module. Measure the voltage from the antenna enable signal circuit of the radio antenna module to a good ground. Voltage measured should be near B+. If the specified voltage is measured, test the antenna enable signal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. If no failures were found, replace the radio. Refer to Radio Replacement for service procedure.
Defective radio antenna buffer. Replace the radio antenna buffer. Refer to Radio Control Module Replacement for service procedure.
Defective radio antenna module. Replace the radio antenna module. Refer to Radio Antenna Module Replacement for service procedure.

 

[emti309]

I am struggling as to what to do at this point. I am almost 100 percent sure that its the head unit after using the coat hanger test and only being able to get 2 stations and the one Columbus station that puts out a strong signal with some static this is status quo. Now I have a new free radio from my sister its a nice Panasonic aftermarket radio that she had in her car before she totaled it. All I need is to get the installation kit and harness which I priced out at $20.00 now that wont give me my steering wheel controls but that would cost me and arm and a leg. So Should I just buy the harness just a few dollars and the antenna adapter and try that then permanently install or continue this chase down the rabbit hole.

 

[coolasice]

I am struggling as to what to do at this point. I am almost 100 percent sure that its the head unit after using the coat hanger test and only being able to get 2 stations and the one Columbus station that puts out a strong signal with some static this is status quo. Now I have a new free radio from my sister its a nice Panasonic aftermarket radio that she had in her car before she totaled it. All I need is to get the installation kit and harness which I priced out at $20.00 now that wont give me my steering wheel controls but that would cost me and arm and a leg. So Should I just buy the harness just a few dollars and the antenna adapter and try that then permanently install or continue this chase down the rabbit hole.

It would cost nothing but 15-20 mins to narrow down the problem with a multi-meter...

 

[emti309]

It would cost nothing but 15-20 mins to narrow down the problem with a multi-meter...

I am confused as to where to use the multi meter as I understand I have to turn radio on and disconnect the antenna radio module which I have no idea where it is if its in the headliner I don't think I wanna tear it down to test If I am wrong please feel free to correct.

 

[coolasice]

I am confused as to where to use the multi meter as I understand I have to turn radio on and disconnect the antenna radio module which I have no idea where it is if its in the headliner I don't think I wanna tear it down to test If I am wrong please feel free to correct.

Judging by the pictures, the antenna module ground strap is attached to the back of the hook on the passenger side rear. I bet if you remove the c pillar you would see it.

 

[coolasice]

What was your outcome?