An Audio Question... BMW E39 '98 528i/5

[Ed CT]

Hey, all,

I'm trouble-shooting my audio system for only some of the speakers working. I've traced it back to somewhere BEFORE the amplifier.

1. What exactly is the "Head Unit" - is it the unit with the cassette deck? the MID? or is there something else hidden in the dash. I searched and couldn't get a definative answer.

2. And, more specifically, from where do the "Head Unit ... Outputs (+,-)" originate. These are pins 1 thru 4 and 14 thru 17 on the amp's 26-pin connector.

Thanks for any help. If I resolve this thing, I'll post the fix, since I've seen multiple questions on the boards regarding the problem of some speakers not working.

[Ed CT]

FIXED! But, it's not logical...

After trouble shooting the thing on & off for a few weeks, I think it's resolved by replacing the amp.

All the testing that was done pointed to the head unit being the culprit: This included replacing the original amp - a Loewe unit - with another OEM Lear amp to see if that fixed it., But the same problem persisted, that being the right rear speakers and some of the front mids & tweeters not working. the wiring connections all checked out good. So, the logical conclusion was that it was a bad head unit.

I bought a used head unit & amp, thinking that all I needed was the head unit (the amp was a deal so I bought it, too). Just for the heck of it, I put the used amp in to see what would happen. This amp was an Alpine, and it worked - all speakers are working, albeit some of the tweeters are faint.

So, there are at least three different OEM amps in the E39s - Lear, Loewe, and Alpine. Looks like the Alpine outlived the other two. I may try out the head unit at some point just to see if it makes a difference in the speaker quality. I'll report back if anything new happens.