2007 Rear Window Defroster Kills Radio Reception?
 

This Accord has one of those Shark Fin antenna that is located on the centerline of the vehicle's roof just in front of the rear window. I'm told that is the XM radio antenna. I've read that the AM/FM radio antenna is located in the rear window.


When I turn on the rear window defroster the FM radio reception drops to near zero...just a hiss coming through the speakers. When I turn the defroster off and the FM radio returns to normal.


WTH? Is this normal?

There is a pre-amp for the antenna feed that may be defective. It is behind the C-pillar trim (rear window trim?). Shop manual did not mention any way of testing the pre-amp.

good luck

Thank you sir for the advice. As a guess, I would say the pre-amp is working because reception of weak FM stations even in deep fringe areas is excellent. As long as I never turned on that rear window defogger, I rated this radio as among the best factory stock receivers I've had in a vehicle.


Does the manual suggest that the defogger killing reception points towards a fried pre-amp?


Did the manual specify which side of the car it was located?


I've read on the net that cars that have had aftermarket window tint removed 'may' have had either the antenna wires or defogger wires damaged in the removal process.


There's no evidence this vehicle had aftermarket tint and all elements of the defogger were working last Friday morning when Ohio had a good frost in my area.


In years past, defogger wires and antenna wire were sandwiched in the laminate of the glass. A body man that works in my factory told me that due to delamination issues the wires were now located on the inside surface of the glass. I'll check that out tomorrow and take a magnifying glass to the wiring runs.

Manual does not provide any diagnostics that I found, however I did not perform an in-depth search.


I don't have manual w/ me (on road) to review, however I was unable to determine location in my brief review of problem.


Have you investigated whether problem is related to alternator performance (heater on but engine off). If noise level is much better, alternator is likely source of noise. It may be a defective rectifier or possibly damaged noise filters on the alternator.


I have an MDX w/ antenna in rear side window and provides terrible reception (very lmited range). I like the idea of embedded antennas but the implementations are not ideal.


I've become an XM fan after my first TSX w/ this feature.


good luck

The reception gets killed with or without the engine running and with any of the combination of the various climate control settings.


It seems to be strictly an interference issue with the rear window defogger.


Anyone remember way back when...when General Motors laminated the AM/FM antenna into the windshield and every time the wipers were used and passed over the antenna wires the reception signal would drop out? When it rained the radio would get turned off and an 8-track or cassette tape (Am I dating myself?) would get slammed into the tape drive to eliminate the insanity of a modern radio that was sabotaged by the attempt to eliminate a system that worked since the days of Marconi...the antenna mast.


The Accord's problem reminds me of that bit of engineering genius.


And putting a pre-amp in the C-pillar? Behind all that trim? Brilliant.

I read your post in regards to this problem about the rear window defogger and the radio interference and saw that there was no solution posted . After some research on the EXACT same problem on my 05 Honda civic coup I found 3 possible solutions to the static problem. The first one I was told that works was to have the rear window replaced as it was explained to me there was a defect in certain rear windows antenna/defogger systems and by replacing the the rear window it fixed the problem. 2nd solution I was given was to replace the antenna booster box located on the passenger side behind the plastic cover by the rear window. Both of these solutions seemed a little drastic since basically the radio system works until you turn on the rear defogger with the radio. My solution which I haven't tried yet is going to be to install a couple of capacitors into the circuit by the booster box to help filter out any RFI generated by the defogger once turned on . It should be a relatively simple install with a multi meter and cheap quick fix once I receive my parts order from Ebay . ....
I hope this info helps you out ! Ill keep you posted on my experiment .

Honda1701, Thanks! Please do keep me posted on your capacitor solution and let us know 'where', inline, and on what wire you install the caps if successful.

After owning this '07 Accord for a few years I have turned on the rear window defroster a few times without killing the radio and turning the reception into static noise, but I would estimate that 99% of the times I have used the RWD with the radio turned on the reception goes to static.

Agree that replacing a window glass or booster amplifier is a bit extreme.