I have a 2002 X5 4.6is, built 02/02. This model is pretty loaded, including NAV, DSP, CDMA Telephone, etc. It has several minor, but annoying and puzzling electrical issues: Intermittent AM radio failure - About 10% of the time, while on the AM band, a tuned station will play for 1-2 seconds, then disappear. Then there will be no AM reception and no station will tune. Meanwhile, FM band works fine. If I power the radio off, then on again, the same behavior will occur - the station wil come on, produce audio for a second or two, then disappear. This behavior is completely random; there is no correlation between failure and internal/external/operational temperature, vibration, or anything. And as noted, it only occurs part of the time. Intermittent vent fan while car is off - Perhaps 2% of the time, after I've turned the car off, removed the key, and walked away from the vehicle, I will hear the ventilation fan come on and off at varying speeds for a varying duration. Center console monitor out completely - About six months ago, for a period of about 2-3 weeks, the center console monitor (and all its associated functions i.e. radio, NAV, etc.) went blank and inoperable. Specifically, it would operate normally for about 30 seconds after the car was turned on/started, then drop out. The other associated behavior during this time was a constant draw on the battery which would kill it after 2-3 days. Inexplicably, this behavior suddenly ended, and hasn't occurred in the past several months. NAV DVD stays on - While the car is off and key removed from ignition, the NAV DVD box at the rear of the car intermittently but continuously operates. The red "power" lamp illuminates, and you can hear the DVD spinning up and down in the unit. Then it will stop for awhile, and seemingly at random start up again - all while the car is off and key in my pocket. I have attempted to have these problems serviced, but the typical diagnosis/treatment has been to simply replace X, Y and Z boxes at costs of thousands of dollars and hope that solves the problems. For example, I have been told to replace the "final stage" unit and the entire NAV system. I wish to get a more diagnostic approach to the problems. They all seem to be related to the center console monitor; I expect there should be some diagnostic way to detect incorrect current draws or isolate and identify the electronics involved. Any ideas?
I can't speak to the other problems, but if the suggestion about the "'final stage' unit" was in response to the blower fan having a mind of its own, that was an accurate diagnosis. The final stage resistor is a key component in the fan speed control circuit. As it fails you lose partial or total control of the blower speed, including during the HVAC self-diagnostic routines that run after you shut off the vehicle. Around 2000-2002 they were known to fail prematurely in some models--I know the E46 was affected but I suspect it was hit-or-miss across all models that shared the same part. I had one die under warranty, its replacement headed south about 100K miles later and the third one--judging by the beefier heat sink on the updated part--will probably outlast the rest of the car. If the blower behaves normally while driving, you might not need to replace the resistor pack yet. It's normal for the fan to run as you described, for short periods, from time to time. If it continues for more than a few minutes, I'd think about replacement soon. (An FSU failure during the diagnostics can ramp the blower to full speed when you're not around and kill your battery overnight...guess how I know.)
Not sure where you live, but if you are in a cold climate I am guessing this problem will resurface once it gets warmer out. I once had a car that the radio display would work at start up and then fade out as you describe in the summer months (or not at all on hot days). During the winter it was more dependable. Sorry I can't offer any real help.
NotTheStig: Thanks for the good info re the FSU. I gather it should be normal for the HVAC self-diagnostic routines to run for a few minutes after vehicle shut-off... but for how long? No more than 5 minutes? 10 minutes? granthr: I live in southern California; warm climate. I can try leaving the car out in the warm sun and see if that causes any specific behavior... Thanks and keep those ideas coming...
