Keyless Entry Installation

318i Modification -
Keyless Entry Installation

Many E30s have problems with door locks. Mine were starting to stick. The passenger side door lock didn't respond at all to the key and the driver's side lock was starting to get problematic. On some days, I'd have to turn the key several times to get it to unlock or lock. My trunk lock is the only one that works perfectly.

While researching how to fix door locks, I ended up looking at keyless entry and alarm systems. Personally, I hate using the key to get into the car. My key has no light in it and at nights I really have to feel around the lock to make sure I don't scratch up the car. I asked the E30 forum on how well the Stellar kits are for the E30 and how difficult the installation is. A member by the name of Chris325/325i says that he installed keyless entry for $30 - which is significantly less than the $100 Stellar keyless entry system. Inquiring further, I learn that installation is very simple and that I can buy the keyless entry system on eBay. From the eBay seller "mypushcart" I ordered the Omega Research Keyless Entry REC-43T. The seller said that the kit will come with instructions on how to install it into an E30. I couldn't wait and I ordered it at the hefty "Buy-It-Now" price of $25.

When I received the system, I was surprised how simple it was. For my application there are only four wires to connect: 12v, Ground, Unlock, and Lock. There are some other features such as trunk open that I am not going to use. Below are the instructions on how to install this unit into an E30. I decided to mount it in the trunk rather than in the driver's side foot well area.

One warning with this modification. Make sure that at least one of your door locks is fully reliable. If the battery ever dies, the keyless entry system will not work and if none of your door locks are reliable, you will be unable to get into your car. For me, my trunk lock is 100% reliable.

Tools/Supplies Needed:
Utility Knife
Soldering Iron/Electrical Tape
Wire Taps/Crimp Tool
Double Sided Tape
In-line fuse carrier
1A fuse

Click on the thumbnails for larger pictures.

Here is a picture of the unit.

Remove the tail light bulb carriers by turning the knobs on the back and carefully pulling them straight out of the tail lights. Pull back the trunk lining near the rear trunk lock to expose the wires. Also remove the plastic trim that covers the battery.
I used a knife and cut away the material that was protecting the bundle of wires. As you can see, I used the knife to strip back insulation to test wires.

Unfortunately the wire colors in the wiring diagram given by the vendor did not match any of the wires in my car. This may be because the wiring diagram was meant for the driver's side foot well. I grabbed my trusty multimeter and found out what wire was what. Luckily, you can benefit from my work. Connect the wires as follows:

Trunk Wire
Wire Function
Omega Wire (connector)
Brown Ground Black (white)
Green & Black Lock Green (red)
Green & Purple Unlock Blue (red)
See below 12V Power Red (white)

I was unable to find a constant 12V wire in this bundle so I ran one over to where the battery and put in an inline fuse with a 1A fuse. I intend to run this wire over to the power antenna or the truck light wire that is near driver's side trunk hinge. I just need to make sure they are constant 12V.

As you can see, I soldered these connections. I used the knife to strip back more insulation on the wire and then soldered on the keyless entry wire. As an electrical engineer and a car enthusiast, I will not rely on crimp connections.

I bandaged up the wire bundle with electrical tape. Don't be stingy. Replace the trunk liner and tail light carriers into the tail lights. Stretch the receiver's antenna out along the trunk area to give maximum remote range.
Double sided tape secures the unit to the trunk wall near the battery. When the plastic trim is replaced, the unit is totally hidden. Beware that if your trunk leaks, this is a bad spot. I may end up moving up upwards behind some trunk lining, but as far as I can tell, my trunk is water tight.


What is not to love about this system. The cost is great and the functionality is great. I would like it if the interior lights went on when I unlocked the door with the remove, but that is a project I will get to in the future. The range is pretty good. Since the antenna is in the trunk the range is dependent on what angle I am approaching the car. Overall, I am very happy with my $30 investment. In the future I will find a way to have the interior lights go on for a few moments when I unlock the car.

One more concern is about double locking your car. I read that if you double lock the doors with the key and then use the keyless entry, you might damage your locks. I haven't confirmed this and haven't tried, so beware.



Disclaimer: I am not a professional mechanic. Information this page should be used at your own risk and discretion. Different models and model years may be different than my 1991 318i. Read: If you screw your car up following my instructions, sorry. Isn't it sad that in this sue crazy world you have to put a disclaimer on your web page?