Rear Defroster interferes with FM radio???

[nra0707]

I noticed this morning that when the rear defroster is turned on, it causes the FM signal to become snowy and staticky. Has anyone else experienced this?

[jst2878]

me too. i just put on the ipod for the frosting duration

[kevinkay]

Old thread, but this just started happening to me.
Anyone know the cause?
I am thinking there is a rip or "leak" in the defrosting grid that gives off electrical current that will cause interference?

[Qsilver7]

Originally Posted by kevinkay

Old thread, but this just started happening to me.
Anyone know the cause?
I am thinking there is a rip or "leak" in the defrosting grid that gives off electrical current that will cause interference?

Since the radio antenna on the SAVs & Tourings is in the rear right (cargo area) glass...I'd definitely check all the amp/trap circuits (#4 & #2) as well as the suppression filters (#7s). The cables that run to the radio antenna is #5 & #6 in the diagram below.

Unlike the sedans where the rear defrost & radio antennas as both incorporated into the same (rear window) glass...the SAVs & Tourings may have wiring that has come loose or fasteners that have come loose and the wires are running next to something that is causing interference. (this happened on my 540iT...I had horrible FM reception...then one day while messing around in the right rear panel...I pushed some wires out of the way while the radio was on and the static stopped).

RealOEM.com * BMW E53 X5 4.4i SINGLE PARTS F ANTENNA-DIVERSITY

[kevinkay]

I can't find the suppression filters!!??

there is one on each side, Looking behind the 2 back compartments (what I call my "trunk" - fix a flat, tools, bungie cords, qt of oil - all hide back there), even pulled up the floor, can't find them!

[Qsilver7]

I believe they are behind everything...when you pull all the components out.....they are behind the back insulating panels...between that and the metal. If you still see panels....then you haven't gone deep enough.

In fact, this was just discussed a few weeks ago, and if you scroll down to post #9...you'll see animage of item #4 inthe diagram...which is also mounted behind all the panels and is next to the metal: http://www.xoutpost.com/bmw-sav-foru...e-antenna.html

[kevinkay]

THANKS for the help-
I found the suppression filters and the amp
They are both in the upper tailgate.
My problem is fixed. (at least for tonight)
First I cleaned both suppression filter connections (static still with defrost)
Then I cleaned all connections on the amp (static still with defrost)
Then I disconnected ALL connections from amp - including the connection that directly connects to the 2 terminals of the defrost (top maroon connector in photo). STILL static with defrost (with no power to glass field) and curiously the radio still worked fine without defrost pressed (with no antenna hook up?).
Then I pulled the 30amp fuse for the rear defroster and NO static when rear defroster pressed (but rear defroster not working).
Then I noticed a clicking when the rear defrost was pressed, traced it back to a relay in the back cargo fuse panel. Pulled the relay, put back the fuse, no static in the radio when defrost pressed (but defrost not working?).
Finally, put back the relay
1. no static in radio when defrost pressed
2. no "click" when defrost pressed
3. I need snow or frost to make sure the defrost is still working
4. I have a bad relay or just loose connection in relay or fuse?

[kevinkay]

Update....back to being problematic.

what I thought was antenna wires in the suppression filters is actually the 12v feed into the defroster field. Pulling either one kills the static (but also the defroster)

I am back to thinking its a tear or leak in the foil field.

[BMW BOB]

Anybody ever fix this issue. I just bought one with the same issue. The last owner thinks it started when they installed a new heater panel a few years back.

[kevinkay]

I still haven't figured it out.
Last I thought was breaks in the grid so I went through and tapped strips of aluminum foil anywhere I thought there could be a leak or break - did'nt help.

another clue - In my case the radio goes static when the defrost button is pressed and lit, BUT stays static even after the timer had turned off the rear defrost and light. I have to hit the button again- turn it on, then turn it off for the radio to clear.