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Old 01-25-2013, 05:48 AM
bsell bsell is offline
Black Squared
Location: Western Germany
Join Date: Apr 2008
Posts: 421
Mein Auto: 1998 535 COSMOSSCHWARZ ME
Most clear schematic I've seen...

Originally Posted by QSilver7 View Post
Or it could be simply be the wires that are running to the rear windshield have dropped or are too close to one another and is causing the static.

Drop open the cover on the left side of the trunk and look for the bundle of wires that work their way to the rear windshield (that are also associated with the antenna in the rear window). Manipulating these bundles (while the radio is on) may reveal which wires are too close to each other.

You can see the antenna wiring (#5 in diagram below) that runs from the amps in the C-pillar:

(this illustration shows the e38's IHKA control panel...but the e39's IHKA panel is wired up basically the same way)
So my radio reception is good but I have no rear defrost...yet the side mirrors defrost just fine.

Took the C pillar covers off to find I have neither power or ground (via test light) to the heating elements and the ground into the driver's side module is good but no ground to the grid.

So are both controllers most likely shot? Edit, saw on another post that you have 10 minutes to verify power before it stops applying juice (to prevent overheating) and the rear defroster turns off when system voltage falls below 12.2V. I did see a brief flash on the power side, then checked system voltage and found it at 12V, even with the battery charger assisting. (Left this info for others' use in the future.)

Quit being a baby (it's below freezing today) and opened the garage, started the car and viola, power to the grid but no ground to the grid.

Took apart the FM amplifier to find the solder blown off the ground lead where it joins the PCB. A couple minutes finding the soldering iron, applying heat & new solder and now there is ground to the grid. I just hope the original solder job was weak from the factory, otherwise the next time it might burn up the PCB...

This is a 1998 (Feb build) Euro 535IA.


Last edited by bsell; 01-25-2013 at 07:12 AM.
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