BMW E91 Diversity Antenna Module Voltage Test Troubleshooting

If your remote fob key doesn’t open and lock the car & comfort access doesn’t work. Then it could the wiring that runs to the trunk lid that is broken. It could also be that water has got into your diversity antenna and fried the microchip. I had both! The wires from an old Apple laptop power adaptor are what I used to repair mine, standard wires are too brittle and will break again.

[@DevinGoodwinlv]

is there a part 2 to the video? it kinda ended a bit too quick

[@xmagic4516]

My car lose the 12v tension from the top first wire after 1-2 minutes. I mean if is activated from that button,it will work but if you leave it for like1-2 mins,it loses…
Tried with another unit and it does the same thing. Maybe both units are dead.
Any suggestion pls ? Checked the battery from the remote,it stays like 2,96-3v.
A deep looking at the cables ?

[@danlongson8719]

My first cable is nowhere near battery voltage. Is this most likely cable damage as i have already replaced diversity antenna

[@larsmadsen8678]

I got 0 volts on everything but nr4.. is it fair to guess that I have broken cables?

[@rikobananas6]

At the point when I shot my video I had already replaced the wiring. The broken wire or water ingress caused the failure of my diversity antenna. Replace the wiring first then see if your fixed, if not then next phase is check the voltages on the antenna

[@rikobananas6]

If you just pull back where the grommets seal to the body and then give a pull on each wire individually you’ll probably find the broken wires pull out

[@linus5699]

Is the second wire for output signal? I have O volts , and not sure if it is a broken wire problem, or diversity antenna problem.

[@cognote]

Hello! thanks for your video... I have checked the readings with the voltmeter and are very similar to your "good" unit... shall I give it a go and replace the module still?... its driving me nuts not having the rm operational....

[@rikobananas6]

Check everything else first like your remote battery. Have you already replaced the wiring?

[@lewisgarrott5389]

mine only works near the trunk..what should I check?

[@OmarShaffi]

Both of my fobs are not working and all fuses seem fine. I’ve opened up the diversity antenna and looks pristine and dry no corrosion etc. I tested the voltage on the pins you did and only had one live with around 4v.
Is this the supply side and is it likely that the wiring near the hinge has been ruptured?

[@rikobananas6]

I would investigate your wiring.

[@christerbakken1026]

My car dosent activate when i push the button. Do you know what may be the problem?

[@rikobananas6]

Most likely the wiring is broken between the body and the trunk door

[@bassiebassie1658]

My 4th is also reading almost 5v, but does it really need to be 12v?

[@rikobananas6]

You may need to replace the wiring at the hinge before you test your diversity antenna

[@rikobananas6]

In the video I say 4th wire but I’m actually meaning 4th pin(3rd wire) Sorry.