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Radio Antenna Testing and Replacement
 

Pelican Technical Article:

Radio Antenna Testing and Replacement

Nick Czerula

Time:

2 hours2 hrs

Tab:

$300

Talent:

****

Tools:

DVOM, T25 Torx

Applicable Models:

BMW X3 Sport Utility (2004-10)

Parts Required:

Antenna booster or module

Hot Tip:

Disconnect battery before working with electronics

Performance Gain:

Repair faulty antenna

Complementary Modification:

Install aftermarket radio

Most electrical components on BMW X3 models require programming using an advanced BMW scan tool when replacing. With that said, don't feel you can't replace these items yourself. You also have the option of swapping out used items, which will at times work with programming. I don't have experience with this method, due to my access to a BMW scan tool, but it is something to consider. I have been told programming of used items isn't always required, so this may be an option, but I cannot vouch for it working 100% of the time. If you have experience with used part installation, please share your experience as it will help the Pelican Parts community.

BMW X3 models can come equipped with up to four antenna systems depending on vehicle options.

FM/AM radio (roof antenna/rear window antenna), Digital radio (roof antenna/rear window antenna), navigation system (roof antenna), telephone (roof antenna) additionally: Bluetooth antenna in steering column trim panel for mobile telephone connection.

Two versions of the roof antenna (FM1) are available depending on optional equipment. In the basic version, the AM and FM antennas are integrated in the roof antenna. On option heavy models, the roof antenna can house the mobile phone antenna, AM/FM antenna, GPS antenna and the SDARS antenna.

The high-frequency radio station signals are received by the rear window antennas (VHF, FM1, FM2, FM3). The antenna amplifier / diversity module is located on the rear hatch above the rear window. There are separate amplifiers for AM and FM signals. Both antenna amplifiers are supplied with direct current when the radio is ON.

The signal quality of the currently selected FM antenna (FM1 to FM4) is evaluated and assessed in the antenna amplifier / diversity module. FM antennas are selected depending on whether the signal quality of the received radio station deteriorates in connection with the active antenna or remains strong. When antennas are switched, no interruption is heard. This function allows the greatest FM signal to be used at any given time.

If you have static in FM or AM, the problem may be an amplifier, diversity module or one of the antennas.

Remember your car may have been serviced before and parts replaced with different size fasteners used in the replacement. The sizes of the nuts and bolts we give may be different from what you have so be prepared with different size sockets and wrenches.

Protect your eyes, hands and body from fluids, dust and debris while working on your vehicle. If working with the electrical system, disconnect the battery before beginning. Always catch fluids in appropriate containers and properly dispose of any fluid waste. Recycle parts, packaging and fluids when possible. Never work on your vehicle if you feel the task is beyond your ability.

Our vehicle may vary slightly from yours as models do change and evolve as they grow older. If something seems different, let us know and share your info to help other users. Questions or want to add to the article? Leave a comment below. When leaving a comment, please leave your vehicle information.

In this tech article I will show you how to replace the antenna amplifiers and antenna diversity module. I will also show you how to locate an open circuit in the antenna window grid or module connections.

The antenna diversity module in mounted to the tail gate (red arrow).
Figure 1

The antenna diversity module in mounted to the tail gate (red arrow).

The antennas amplifiers (red arrow) are mounted to the sides of the tail gate, left side shown, right is similar.
Figure 2

The antennas amplifiers (red arrow) are mounted to the sides of the tail gate, left side shown, right is similar.

Remove the tail gate trim panel.
Figure 3

Remove the tail gate trim panel. See our tech article on tail gate trim panel removing. To replace one of the antenna amplifiers, start by unplugging the electrical connectors (red arrows). Squeeze the release levers and pull the connectors straight out to remove. Then remove the T25 Torx screw (yellow arrow) along with the amplifier. Left side shown, right side amplifier is similar. When installing, be sure to align the plastic pin with the hole in tail gate (blue arrows).

To replace the antenna diversity module, start by unplugging the electrical connectors.
Figure 4

To replace the antenna diversity module, start by unplugging the electrical connectors. For the coaxial connectors, press the release tab (yellow arrows) and pull it straight out. If your vehicle has a connector (blue arrow) above the coaxial connector, it pulls straight out

Working at the right side of the module, pull the electrical connectors straight out (red arrows).
Figure 5

Working at the right side of the module, pull the electrical connectors straight out (red arrows). When removing the top connector, it is best to use a pick to release the tab (yellow arrow) then remove it. This way you don't accidentally pull the soldered wires off the glass (blue arrows) if too much force is used or you slip.

Then loosen the T25 Torx screw (red arrow) and remove with the module at an angle, pulling the mounting tab out of tail gate (yellow arrow).
Figure 6

Then loosen the T25 Torx screw (red arrow) and remove with the module at an angle, pulling the mounting tab out of tail gate (yellow arrow). Replace with new, then code using a BMW scan tool.

To test the rear window antenna grid, start by disconnecting the black electrical connectors at each amplifier.
Figure 7

To test the rear window antenna grid, start by disconnecting the black electrical connectors at each amplifier. Then, connect the test leads of your DVOM to each electrical connector (red arrows). Set your DVOM to Ohms, the rear glass should have about 2-5 Ohms (yellow arrow) of resistance. Any more and you could have a faulty window grid.

To test for a break or high resistance in the window grid, connect one lead of your DVOM to one of the antenna amplifier connectors.
Figure 8

To test for a break or high resistance in the window grid, connect one lead of your DVOM to one of the antenna amplifier connectors. Then use the other test lead to touch different areas of the grid (red arrow) until the place of high resistance is found. When testing the grid, your resistance should be about the same as it was in the previous step.

To test one of the antenna amplifiers, measure Ohms through the amplifier, should be close to zero Ohms.
Figure 9

To test one of the antenna amplifiers, measure Ohms through the amplifier, should be close to zero Ohms.

There are connections at the rear glass that go directly to the diversity module.
Figure 10

There are connections at the rear glass that go directly to the diversity module. The wires should have about 2-5 Ohms. Connect your DVOM to each wire (one at a time) (yellow arrow), and measure along the grid (red arrow). Look for open spots, infinite resistance.



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Page last updated: Sun 12/10/2017 03:11:21 AM