MAKG1
Touchdown! Greaser!
- Joined
- Jun 19, 2012
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- 13,411
- Location
- California central coast
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Display name:
MAKG
OK, the BMW is developing some interesting electrical behaviors, and I'm having some trouble finding the source(s). It's a 2000 323i (e46) sedan with a stick and "base" ("business CD") radio with no CD changer nor amplifier in the trunk. It seems to be something in back, but everything I can find makes no difference.
1. Backup lights inop. Bulbs are good.
2. Rear defogger inop. I can measure a good voltage drop across the grid, but it doesn't evaporate anything and doesn't get warm. The relay light does turn on.
3. Poor radio reception. Doesn't matter if the rear defogger is on or not. If I disconnect the antenna feeds from the diversity module, all reception goes away entirely. All electrical connections to the rear glass look really good.
4. Headlights intermittently drop out for a split second.
5. Right rear and right front lights-out indication trips intermittently and then goes away with no intervention.
There are no discernable drivability issues and the check engine light is not on. I haven't checked for pending codes. Cranking is normal, so it isn't a dead body ground (there is no separate engine block ground to the battery in this vehicle -- it ALL goes through the body). I can find no substantial corrosion anywhere on the vehicle.
I've taken both the C pillars off to clean grounds for the diversity module and wave trap (using electrical contact cleaner). I've cleaned the battery ground (in the trunk). What I haven't done is check out the alternator and engine block ground, as I'm now starting to suspect I have a voltage regulation problem.
Any pointers from someone more familiar with these very complex electrical systems than I am?
1. Backup lights inop. Bulbs are good.
2. Rear defogger inop. I can measure a good voltage drop across the grid, but it doesn't evaporate anything and doesn't get warm. The relay light does turn on.
3. Poor radio reception. Doesn't matter if the rear defogger is on or not. If I disconnect the antenna feeds from the diversity module, all reception goes away entirely. All electrical connections to the rear glass look really good.
4. Headlights intermittently drop out for a split second.
5. Right rear and right front lights-out indication trips intermittently and then goes away with no intervention.
There are no discernable drivability issues and the check engine light is not on. I haven't checked for pending codes. Cranking is normal, so it isn't a dead body ground (there is no separate engine block ground to the battery in this vehicle -- it ALL goes through the body). I can find no substantial corrosion anywhere on the vehicle.
I've taken both the C pillars off to clean grounds for the diversity module and wave trap (using electrical contact cleaner). I've cleaned the battery ground (in the trunk). What I haven't done is check out the alternator and engine block ground, as I'm now starting to suspect I have a voltage regulation problem.
Any pointers from someone more familiar with these very complex electrical systems than I am?