YES!! THE DIVERSITY ANTENNA problem HAS BEEN DEFEATED! see inside!

[Cobra Jet]

Well, I know EVERYONE has an issue with their BMW diversity antenna when installing an aftermarket stereo system... and I believe that bmwpower and myslef have finally DEFEATED the "reception issues"!!!!

Here is what we both did and it WORKS 100%, with CRYSTAL CLEAR STEREO RECEPTION...

The stock BMW stereo harness incorporates a WHITE wire for the DIVERSITY ANTENNA. This wire runs as such:

1) Main stereo wiring harness TO STEREO
2) from the main wiring harness TO THE DIVERSITY ANTENNA
3) from the diversity antenna TO THE FACTORY AMP

In order to get PERFECT stereo reception from an aftermarket stereo you NEED TO DO THIS:

A) on the back of *most* aftermarket stereos, there is a BLUE/WHITE lead. This lead is commonly referred to as the POWER ANTENNA lead...

B) take the WHITE wire from the BMW STOCK HARNESS and connect it to your BLUE/WHITE (POWER ANTENNA) lead coming off the back of your aftermarket stereo.

C) in the trunk, DISCONNECT the WHITE WIRE from the stock stereo harness. You do NOT want this END of the WHITE WIRE hooked up to anything at all. DO NOT CONNECT it to your amp, DO NOT connect it back to anything. All you want to do is tape up the end of it and just tuck it back away behind the trunk liner/panel.

D) Be sure your coaxial antenna lead coming from the CAR is hooked/plugged into the back of your STEREO.

E) test the stereo/radio reception BEFORE re-installing the head unit back into the dash. With the car turned to "ON", you should be picking up any radio station in your area. With the car turned on and RUNNING, you should STILL be picking up any radio station in your area and the reception should be CRYSTAL CLEAR.

We both have our aftermarket stereos (both Alpines) installed this way and both of our head units (the one in his 535i and my M3) pick up radio stations EXTREMELY CLEAR with NO other issues.

I think what the problem is, if you look at the BMW factory wiring diagrams, it shows the white wire hooked into the stereo, it then goes into the diversity antenna, then goes into the BMW factory amp. Well, most stereo install shops AND the "do it yourself" installers will do exactly the same install, follwing all of the wiring diagrams.. Which, if you do look at the wiring diagrams, it may be correct on paper to follow the same route & install procedure - BUT, for whatever reason, the diversity antenna does NOT work the same way when installing an aftermarket amp/stereo when following the factory wiring diagram layout.

If you have the WHITE wire in the trunk hooked up to your AFTERMARKET AMP, disconnect it completely and just tape it up. As long as that WHITE wire is hooked up at the AFTERMARKET HEAD UNIT to the BLUE/WHITE wire (power antenna lead) coming off the head unit, you should be getting PERFECT stereo reception when listening to AM or FM!!!!

The ONLY other thing that will affect the head unit from not picking up CLEAR reception after doing the above is:

1) Your rear window tint (if applicable) has metallic particles in the tint itself. This WILL interfere with the diversity antenna, since the antenna does run through and is imbedded in the rear glass.

2) Your connections at the actual diversity antenna distribuiton block may be LOOSE. The only way to access this distribution block is to remove your DRIVER'S side rear interior C-pillar panel. This panel is not the easiest to remove, but with ease and PATIENCE, you can remove it. Once removed, check the connections and make sure the coaxial cables and wires going to the diversity antenna block are SECURE.

I hope all of the above was helpful and I can say that our radio reception is GREAT! So, the above procedure DOES WORK.

:

[2pak]

im a little confused... isnt the blue/white wire from the alpine, i have one too (7894) connected to the blue wire on the bmw harness and that allows for powering the system..... i may be confused since i did it a year ago. also, define crystal clear reception, i think my reception is pretty good although it tends to be rough one 1 station.... could u take a look at my thread about my stereo install tmrw and see if u can give me any advice... your writeup and pics that u posted today are a big help

[Cobra Jet]

on the back of the Alpine (most of them) - there is a SOLID blue wire AND a blue/white wire (this wire is blue with a solid white line on it).

The SOLID blue wire from the Alpine is your amp turn on lead.

The BLUE/WHITE wire from the Alpine is your power antenna lead.

In the BMW factory harness, the DIVERSITY ANTENNA wire is SOLID WHITE. This is not to be confused with the black coaxial antenna lead.. that is totally spearate from the WHITE wire...

I don't recall what the blue wire is on the BMW harness, I don't have a wiring diagram in front of me at the moment...

To have the antenna hooked up properly, you should have your Alpine's BLUE/WHITE wire hooked directly to the BMW's WHITE wire.

For amp turn on, you should have your Alpine's SOLID BLUE wire going to your aftermarket amp (if running one).

At the moment, I just cannot picture what the blue wire would be in the BMW harness....?????

If you do a search on my user name (ID) here on the site, and just search in the Car Audio forum, you will come across a large post that I did a while back, probably like last year sometime. In that posting, I have detailed almost everything there is to detail about my complete stereo install (more so that the current thread I have with the pictures of it)... There is alot of useful info in my old post to help you out. I'll search for your other post and review your issues.

[Drea///M3]

OK I'm in a different boat; I'm still using my factory amp so I can't cut the white wire(which is the remote turn-on wire for the stock amp). I just finished installing my Nak CD400 and I get horrible reception....REALLY HORRIBLE reception. It can't be the antenna b/c it was just working 10mins before I hooked up the Nak unit. ALSO I can't hook up the antenna wire from the aftermarket headunit b/c when I turn off the tuner, it grounds the antenna and therefore turns off the stock amp which turns off all my speakers...I need a sure fix for this b/c I want to find out if it's my connection(s) or if it's my headunit. PLEASE HELP!!!!!!

I just found this while looking for my "fix."

Different fix?

[Drea///M3]

OK I just had a theory...If you look at Cobra Jet's "fix" and the other "fix" I posted they both have "more power/current" going solely to the antenna amp. CJ's fix has the power going to the speaker amp totally cut off, so all the power/current is going to directly to the antenna amp. The unofficialbmw.com's fix has the power/current re-directed from the speaker amp back to the antenna amp.

[bmwpower]

The link to the fix you listed should work, however the C-pillar is VERY hard to remove and often breaks in removal.

I would run a new wire (~16 gauge) from the headunit's remote turn-on to the factory amp. Make sure the white factory harness wire (behind the headunit) is connected to the power antenna lead on the headunit and DISCONNECTED from the amp.

This is exactly what Cobra Jet did in his install.

[Drea///M3]

OK I'm going to try that....Well I'll try to disconnect the white wire from the stock speaker amp(without damage) first to see if I get better signal...I'm dreading the day I run 2 sets of RCAs to the trunk....And now this....Why can't things just be easy with these cars?: :

[bmwpower]

Using factory equipment is always a PIA. You have to figure out how the factory system is put together before you start throwing new components into the mix.

That's why I always put in aftermarket stuff and wire it up separately (most of the time).

[Drea///M3]

But it still seems like this diversity powered/amplified antenna thing would be and issue no matter what..Now since I've been looking intot his thing I've read about the floating ground "issue," which sounds logical, but should I worry? Some say no problems, but others have said sometime down the line say their headunits' amps get fried. Oh brother what next?

[2pak]

bringing this thread back from the grave.... can i do this if im using both my factory amp and a jl 300/4 aftermarket amp at the same time..... just like drea..... ( i dont know why drea says the remote turn on wire from the factory amp is white though, i think its blue)

[Kenshiro]

On e46's, they're using a VW antenna adapter that sends +12V up through the antenna lead. I'm pretty sure it'll work on E36 too... going to get one next week from Sounddomain.com

[ASCH MAN]

I just used the regular harness that I got with the radio. I think people are not connecting the amp turn on lead from their radio, to the white wire in the harness. I have never had a problem in the several radios that have been installed in E36's with reception of an aftermarket radio.

[2pak]

audioman,

what you are saying would mean the radio wouldnt come on at all... i read that link that drea put up... about how the power antenna on the aftermarket headunit isnt hooked up, which is exactly what cobra is saying.... my questions is simply if i go ahead and connect the power antenna wire to the white wire from the harness and then disconnect it from the connector plug going into the HK amp.... this is what cobra jet is saying but i dont know why drea is saying that he can't do this because he still has the factory amp which i do to... maybe drea doesnt have anything else besides the factory amp and i was just misunderstanding what he was saying. I will try it tmrw and let you guys know. Worst case scenario is that i end up wasting a precious butt connector.

[jel014]

Hi,

I'm wondering if we disconnect the white wire going into the amp in the back, does that mean the amp won't turn on anymore? I just installed a clarion unit, and i'm getting bad radio signal. I suspect its the same problem as what CJ posted. Just want to make sure that if i do CJ's fix my amplifier in the trunk will still turn on.

Thanks,
James

[bmwpower]

You still need to run a new turn on line from the radio to the amp.

[patrick S]

if you think you have current draw problem why dont you use tiny relay? aftermarket stereos have different treshold on reception unit. also aftermarket units have more sound quality whitsh will bring up any receiption problems that you never noticed with original units. for example an expencive alpine unit will give poor stereo (it will switch between stereo and mono) but cheap pioneer will not have this problem

[chooks1234]

Will this procedure help with AM radio reception, too? I just installed an Alpine 9507 and get no AM reception. I don't listen to it alot, but I like to catch sports radio or a sporting event every now and then...

[NiTE]

I thought the blue/white wire from the alpine goes to the blue wire on the harness...?

[WK446]

Phil,

I want to thank you *very much* for coming up with the diversity antenna fix.

I searched high and low through the archives sifting through tons of information pertaining to this problem.

I recently had my audio system professionally installed and the installer insisted that a) the radio problem existed and b) that I basically had to live with it. He suggested adding an antenna booster, but conceded that it probably would not help too much.

I went back to the shop about a month later and showed him the instructions you included in your thread. After about 15 minutes of tinkering, the installer returned.

The installer's response was, "I'll be dammed...." (Insert crow eaten joke here)

The radio reception is perfect on FM as well as AM!

BTW, my head unit is a JVC KDSH99 so your fix is not confined only to Alpines!

THANKS AGAIN SO MUCH!:

[2pak]

i just installed a system in my car and did this and my radio reception sucks... it goes in and out... when i move my antenna adaptor to a certain spot its perfect but it goes out then after i move it.... this sucks.

[oraph]

quick question...
is this needed for the non HK audio systems.. for example on the 95 M3s?

[Jayhox]

I also have a follow-up question:

I am about to install a Clarion DXZ845MC headunit in a '96 M3 with the HK amp. Can/should I do the procedure described in the first post of this thread?

Thanks!

[alexrh]

Any pictures of this fix?

Anybody knows where the stock amp is in a e36 convertible?

[David.Dunbar]

Is this an issue with the vert antenna? What the hell is a Diversity Antenna anyway? I am about to install a Nak and still want AM reception. I also listen to FM for about 2 minutes each day when I am in the parking garage and can not see Rock & Roll (XM satellites)

Any pictures of this fix?

Anybody knows where the stock amp is in a e36 convertible?

The stock amp in the vert is behind the rear seat on the drivers side. You can grasp the seat back on both sides of the center divider and pull and it will tilt forward. The amp is in front of the roll over protection cavity and is tough to see with the material in the way. Check this link that has pictures and a description of putting an aftermarket amp in the rollover cavity (that is because he did not have the rollover option). http://home.att.net/~ebaines/e36_stereo_upgrade.htm

Dunbar

[NHenson1]

the blue/white wire on any aftermarket radio is amp turn on. the solid blue is power antenna lead. i am 100% sure, i install stereos for a living and i put systems in cars every single day. not that it makes a huge difference, but it will mess up anyone that doesn't know if they attempt the fix.