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Discussion Starter · #1 · (Edited)
Does anyone know why my 2002 deville WINDOW antennas would have a bad recption.
Can hardly get FM reception...or very faint signal. Replaced both roof signal boosters or antenna fiters but to no avail...I herd that if you are more than
50 km away from radio station it would not ome in to clearly..is this true?
Sometimes when I drive over top of bridges the reception is almost none.

thanks for any help...maybe I have a faulty radio or ground wire somewheres
 

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Discussion Starter · #3 ·
I replaced both antennas DOME amplifiers in top of roof ( front & back )...however taking the front antenna and unplugging it nothing changes but it severely changes the reception quality when I unplug the back window antenna.
Could it be my Radio that would be the problem
 

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If its any help my 98 Deville with a power antenna on the right rear 1/4, the FM radio reception is also horrible.
I though I found the problem when I discovered the antenna was not fully extending but after I took care of that problem it made no difference.
 

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Try pulling the radio out of the dash and hooking up a cheap old school mast antenna to the back of the radio (Radio Shack used to carry them) and see if your reception improves. This will possibly tell you if it's an antenna issue or a radio issue.


This probably has nothing to do with the poor reception especially this time of year. But there's a bulletin on the rear window defoggers causing static.

Poor Radio Reception or Radio Static/Increased Interference with Rear Window Defogger On or Some Rear Window Defogger Grids

Poor Radio Reception or Radio Static/Increased Interference with Rear Window Defogger On or Some Rear Window Defogger Grids May Be Inoperative (Diagnose and Repair Rear Window Defogger Heating Grid) 1997-2001 Cadillac Catera
1997-2002 Cadillac Eldorado
1997-2004 Cadillac DeVille, Seville
2003-2004 Cadillac CTS


Condition

Some customers may comment that the radio has poor reception or radio static/increased interference when the rear window defogger is turned on. Also, some rear window defogger grids may be inoperative.
Cause

This condition may be due to microscopic cracks in the electrically heated grids of the rear window defogger. These cracks may cause electrical interference when the rear defogger is on and this could affect radio reception.
Background

The addition of vertical grid lines to the heated back window defogger circuits has made it difficult to detect broken defogger grid lines. In the past, it was a simple matter to use a voltmeter to check the continuity of each grid line in order to locate a non-functional line. New design back windows have two vertical grid lines that connect all of the horizontal grid lines together, thereby providing alternate routes for the electrical current to follow. This makes the old test method ineffective.
Materials Required


  • Permatex Quick Grid, P/N 15067, or equivalent
  • A small ball of fine steel wool Type 00, or
  • Optional -- A strip of liquid crystal heat sensitive paper, 51 mm x 305 mm (2 in x 12 in) or similar size (Contact Edmund Scientific at 800-728-6999 for part number CR30723-70 or go to www.scientificsonline.com), or
  • Optional -- A portable infrared thermometer, GE-46819, available from Kent-Moore (1-800-345-2233), or equivalent.
Correction

There are three distinct zones across the back window that must be checked. They are:

  • the driver's side outboard of the two vertical lines
  • the passenger side outboard of the two vertical lines
  • the central zone that falls between the two vertical lines
To detect a broken grid line in any of the above three zones and to isolate the exact location of the break, perform the following:


  1. Start the engine and turn on the back window defogger. Important

    The first place to check should be the driver side segment 2 to 3 lines up from the bottom about 380-385 mm (15-15.2 in) from the buss bar.

  2. Take the ball of fine steel wool and twist one end to a point. Move the point slowly across each grid line. Be sure to start at the far side of the zone and move it to the opposite side of the zone. When you bridge the grid line break with the steel wool, you will see a small spark. Repeat the test over the same area to be sure you have accurately located the break. Mark the exact location of the grid line break. Repeat this portion of the test for each grid line. If you do not see a spark at any point, it is possible that there are two breaks in the same line and zone. Close visual inspection using a magnifying glass may be the only way to locate breaks in this case.
  3. The following are provided as a alternative way to detect a non-functional grid line. If available, use in addition to the steel wool.
    1. Method using liquid crystal heat sensitive paper.
      1. Important

        The first part of the test must be completed quickly before the entire surface of the back window becomes warm.

      2. From outside the vehicle, place the heat sensitive paper (dull surface in contact with the glass) against the top driver side grid line. Start the engine and turn on the back window defogger. A distinct color change will take place at each conductive grid line. Repeat for the bottom grid lines until they have all been checked in the driver side zone.
      3. Repeat the process for the passenger side and center area zones.
      4. If no color change is noted for a grid line, place a crayon or china marker check mark beside it. Mark each grid line in the zone where it is non-conductive and therefore not heating up. More than one broken grid line may be found.
    2. Method using a portable infrared thermometer.
      1. Start the engine and turn on the rear back window defogger.
      2. From inside the vehicle, start at the top driver side grid line and slowly run the portable infrared thermometer vertically down the rear window contacting each grid line. You should be able to see a district variation in temperature readings.
      3. Mark each grid line in the zone where it is non-conductive and, therefore, not heating up. More than one broken grid line may be found.
      4. Repeat the process for the passenger side and center area zones.
  4. Use Permatex Quick Grid, P/N 15067, or equivalent, to repair each broken grid line. Follow the manufacturer's instructions.
  5. Wait 24 hours before turning the defogger on, or the repair can be fast cured using a heat gun, 260°C -- 371°C (500°F -- 700°F). Hold the heat gun within 25 - 51 mm (1- 2 in) from the repair point for 2 to 3 minutes.
  6. Recheck the grid line with the heat sensitive paper or a portable infrared thermometer to ensure that the line is now functional and that the repair was successful.
 

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Discussion Starter · #7 ·
thanks guys...I try the old antenna replacement with Radio Shack one...but the same problem persisted...seems like its a ground issue...when I pass on an overpass the signal fades almost out...like my car doesn't ground or is not grounded properly...absolutely no change when I unplug the fron windshield antenna...man what a dull day without a good radio...gonna check FREQUENCY READINGS on front
antenna this weekend and see if front antenna is busted again...was replaced but doesn't seem to work
 

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At this point it sounds like you will need a FSM if you don't already have one. Here's the D&O of the antenna system if you haven't already seen it. Good Luck on you quest grab a satisfactory signal from the air.


The diversity antenna system uses both front and back windows with an integral antenna built between the glass layers of the windshield and as an applique to the rear glass. Any damage to the antenna requires replacing the glass.
A diversity antenna system is designed to deliver the best radio signal reception possible. Two antennas are used to form a diversity system. The primary antenna is part of the rear window and looks similar to the defogger grid. This antenna receives both AM and FM signals. The secondary antenna is part of the front windshield and receives only FM signals.
The antenna reception signals are sorted out by the radio antenna module. The radio antenna module is enabled when the radio is turned on. When the AM or FM band is selected on the radio, the antenna module connects the rear window antenna directly to the radio. In addition, when the FM band is selected an enable signal is sent to the antenna module. Superimposed on this enable signal is the strength of the signal being received by the radio tuner. The antenna module now performs two functions. It switches between the front and rear antennas, monitoring the radio signal strength and combines both signals and phase aligns them to create one strong signal.
 

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Discussion Starter · #9 ·
well...it sounds like I may have shhorted the Radio itself...I have no AM signal at all...and the front windshield antenna is none....so the radio is not functionning properly....I had my car boosted about a year ago...and sparks flew...this could have shorted my radio especially the Antenna components in the radio then ????
Gonna buy a Used deville Radio...and try this....150$ at Junkyards.
 

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If plugging the old school antenna in didn't help it may very well be the Radio.

Keep in mind when purchasing a Radio that the radio requires the VIN# to be programmed into it the radio by the dealer or it will not work (theft deterrent). Most dealers will require the VIN of the car that it came out of so they can verify that its not stolen. Call your local dealer to see what they require to program the radio.
 

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Discussion Starter · #11 ·
thanks for that VERY GOOD information regarding the VIN #, "00 DEVILLE"
I really think the TUNER is out of alignment on my Radio or shorted out.

Will post a note when I have a good radio....thanks again for the replies.

charlie
 
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