Cutting the Cord

If you’ve got a Z3, chances are you’ve also got a RADAR detector. I’ve got an old BEL detector (no V1 flames please, I know Valentine makes the best detector, but the BEL does just fine for me). I’ve had two problems with the detector placement:

Trying to find a secure place where the detector doesn’t rattle

Trying to find a source of power for the detector

I solved the first problem by simply velcroing the detector to the dash. The problem then becomes the power source. I’ve had the car about four months now and I was getting tired of using the cord to the cigarette lighter. In addition to being unsightly and somewhat rattle-prone, the cigarette lighter is hooked up to unswitched power. This means you need to remember to shut the detector off and turn it on every time you leave and re-enter the car.

Not fun.

I originally thought I could tap into power easily, but it turns out to be quite an ordeal. I tried to get power from the main bank of fuses in the engine compartment, but could not figure out an easy way to run a wire through the firewall. Eventually, I decided to use the power from the head-unit of the stereo and a ground from the cigarette lighter. The job takes about three hours. You need to be somewhat handy, need a working knowledge of automotive electrical connections and must be small enough to crawl into the driver’s footwell. Here’s how you can do it too:

Before you begin.

Get a box or container which you can put the screws in. Figure out some way of labeling the screws, they are all different shapes and sizes. Also make sure you have the 5 digit radio code you will need to reactivate the radio. Expect the job to take 2 to 3 hours. READ ALL DIRECTIONS FIRST!

You’ll need:

a phillips head screwdriver

a wirecutter

two tap-in connectors (Radio Shack 64-3052A)

several miniwire clips (Radio Shack 278-1668)

several connectors (optional – Radio Shack 64-3049A)

a 2mm allen or the BMW tool (a 5/64″ hex key)

at least 2 replacement BMW screw head covers

a seven foot wire to run from your detector to the power source

a white, dry-cleaners type coat hanger

electrical tape

a multimeter (optional,

lots of patience

First prepare the car by taking it apart.

Take the top down.

Look in the driver’s footwell and find two small rubber heads securing the front of the console.

Remove the rubber heads by hooking them with a stout paperclip-end from the bottom (the part that faces down). You should be able to hook them then pull out to remove them. They will resist. Be persistent. This will expose the screw head.

Remove the upper screw first, label it “upper”. Then remove the lower, label it “lower”. (Yes, they are different sizes)

Remove the radio:

Be sure you have the 5 digit reset code to reactivate the radio before you disconnect it.

Flip open the two small doors on either side of the radio to expose a small allen nut (It’s actually not an Allen nut, BMW sells a $16 tool to unscrew it, but a 2mm Allen wrench worked for me).

Screw the nut counterclockwise until it stops.

Repeat with the other allen nut

gently pull the radio towards you.

At the back of the radio, remove the antenna plug

Use a screwdriver to gently push up the “locking collar” for the other connections. It goes up about 1/2 inch, but does not come off. If you do this successfully, the entire back plug unit will come off. Otherwise, gently rock the entire connector back and forth, pulling backwards to remove it.

The radio is now disconnected.

Remove the shift knob by pulling straight up – be careful! You can hit yourself in the nose when it comes loose!

Remove the shifter boot – same process as the hand brake (except the “clips” are on the sides).

Remove the foam collar which surrounds the shift knob (Take a minute to note how it goes back in)

Push from below to pop the lighter out

Crawl under the driver’s dash – you will what looks like two large, black screw heads.

Rotate them 90 degrees and they should fall out.

Now remove the large plastic piece which goes around the pedals. You’ll need to pull it “backwards” (towards the back of the car), then push forwards again to get it loose. I ended up fighting with it for quite a while, but it eventually comes out.

Next, run the wires from the detector to the power source.

Cut the dry-cleaner’s hanger into a bent piece about a foot long. You’ll be using it to snake the wires through the defroster vents

Sitting in the Driver’s seat, start at the right most of the driver’s vents and manipulate the hanger till it comes out of the left most vent.

Tape your detector power plug (connected to the cord) to the hanger and snake it back through the holes.

Use one of the mini-clips to secure it to the dash. This prevents the cord from falling into the vents when not in use.

Run the rest of the wire to the A-pillar.

You can just push the wire into the crack which leads to the door.

Just below the console, pull the trim from the door-sill to allow you to run the wire into the console.

Put the trim back into place

Run the wire along the bottom of the dash, securing it with the mini-wire ties.

Feed the wire up around the side of the center console.

Feed the positive lead to the opening for the head-unit.

Feed the negative (ground) lead to the opening for the lighter.

Now Connect the Wires

If you have plugged in your detector to see how it will fit with the wire you ran, please disconnect it now.

Disclaimer – I used a multi-meter to identify the source of switches positive power for the radio. It was the purple/white wire which leads to the plug. If you have a multi-meter, I would advise double checking on your car. BMW may change the wiring harness from year-to-year.

Use the Tap-in connector to connect the positive line to the purple/white lead of the radio harness. You should immediately hear a little voice telling you that you have just voided your electrical warranty.

Disconnect the lighter from the two wires.

Use the tap-in to connect to the brown (unshielded) lead which runs to the lighter.

If you have a multi-meter, turn the car to Accessory and check for proper power at the detector plug. If you don’t have a meter, you should plug in your detector (risking frying it if you have made the wrong connection).

Now put everything back together

Assuming everything went well with the detector test, you are now ready to close up the patient.

The cigarette lighter is tricky to get back in. Before reconnecting it and reinserting it, you must first move the orange collar from the top to the bottom of the unit.

You do this by pushing out (from the inside of the unit) on both the little “wings” at the same time. This requires a little manual dexterity or a lovely assistant.

Once you do this, you can move the orange ring down to the bottom of the unit:

Reconnect the wires to the lighter unit.

Insert the unit into the dash, aligning the small cutout on the left with the tab of the orange collar.

Press in on the collar, it will seat itself, then press the lighter in which will also seat itself.

Before putting the shifter back together, turn on the lights and make sure the small bulb which illuminates the lighter is still in place. If not, re-seat it (it goes to the right of the lighter when looking at it from above, it just fits into a small hole next to the lighter.)

Reinstall the foam collar, shift boot and knob.

Reconnect the head-unit and put it back into the dash, securing with the allen wrench.

Re-screw the console screws and put the new screw heads on.

Reinstall the foot-pedal guards.

That’s it! You can now connect your detector, it will turn on when the ignition is turned on. Now go find your cigarette lighter (or lighter plug) and put it back in! You’ve cut the cord!