Remote Central Locking, Keyless Entry Upgrade (86 BMW e24)

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TimU
Posts: 280
Joined: Tue Dec 14, 2021 2:16 am
Location: Sydney

Remote Central Locking, Keyless Entry Upgrade (86 BMW e24)

Post by TimU »

The BMW E24 is fitted with a factory key operated central locking system. I wanted to add a cheap, key fob/remote to the existing system rather than change it out for a full aftermarket system.

I chose a Steel Mate 386M unit from my local Jaycar Electronics shop (Australia). It cost $50 and comes with 2 remotes, the receiver/central locking module and a very large wiring harness.

The system is advertised as “Universal”, with 2x discrete-looking fobs and includes some good features like 2x Aux Outs for window winders and a boot release trigger. The range seems reasonable, but I haven’t had a chance to test its activation distances yet.

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Installing a remote central locking system into an E24 SHOULD be pretty straight-forward.
The car has all the hardware needed to easily retrofit a remote unit to the factory central locking system.

Unfortunately the Steel Mate 386M instructions are woefully inadequate and made the installation harder than it otherwise should have been.

There are 2 main issues to deal with when trying to fit this particular system into the E24:

1. Totally inadequate instructions that were written for a different system.
2. The 386M sends a +12V pulse to the door locks, however the E24, like many cars, needs to see a GROUND pulse to activate the central locking module.

Dealing with issue 1 was frustrating and time-consuming, but this article will fix that problem for you, dear reader.

Issue 2 was compounded by issue 1, but was easily solved with a pair of external change-over relays to convert the polarity from +12V to GROUND. To get to this solution, I needed to learn there was no other way to configure the unit to send a GROUND pulse out of the box.

Read on for installation instructions.
A formatted PDF of these instructions is attached here for posterity. Other Parts and Tools needed:
• 2x SPDT change-over relays
• Male & Female Insulated Spade Terminals
• Terminal Crimper
• Wire Stripper
• Wire Cutter
• Digital Multi-Meter
• Philips head screwdriver
• Masking tape for labelling wires
• Felt tape for wrapping wires
• Electrical tape for insulation


Steel Mate 386M Remote Central Locking Module

This unit is cheap enough and highly functional, however the included wiring diagram and instructions are rubbish.
They are made for a different unit which includes actuators, whereas this unit just has bare wire ends for connection to the car’s existing Central Locking components.

The instructions below should replace the included instructions.

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BMW E24 Central Locking Control Unit (CLCU)

RHD car shown.
Located above/behind the Glove Box.
Accessible when Glove Box straps are lowered.
Better access when glove box is removed.

Remove 2 screws at the top of the L-Bracket to access the CLCU behind.
Remove 2 screws on the face of the panel to release the CLCU.
Unplug the wiring harness and set the CLCU aside.

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BMW Factory Central Locking Control Unit
P/N: 61311380302 [RealOEM Link]

Supersedes:
61311373323 (11/01/1982 — 06/23/1997), Exchangeable retrospectively
61311367873 (09/01/1980 — 11/15/1983), nonexchangeable retrospectively
61311363806 (05/01/1977 — )

Also found on the following vehicles:
3' E30   (12/1981 — 02/1994)
6' E24   (10/1975 — 04/1989)
7' E23   (01/1977 — 11/1989)

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BMW uses a GROUND pulse system to activate the door actuators.

Grounding any of the Lock/Unlock wires (pins 6, 7, 8 or 9) will Lock or Unlock the doors, fuel door and boot.

The new remote central locking module will tap into Lock and Unlock wires of the doors or boot actuators.

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Installation Options

Two common tap-in points are:
1) At the central locking control unit loom under the dash
2) At the boot release actuator

Installation Option 1: Central locking control unit loom under the dash

I chose Option 1, being a central location with easy access to the Window & Sunroof wires for another project (a Viper 535T One Touch Window Control Module).

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Installation Option 2: Boot release actuator
The boot release actuator (in the boot) is an easy install location if you don’t need to access Window or Sunroof wires.

Permanent 12V is available from the Fuel Flap lock and the Left/Right indicator wires are easily accessible at the tail lights.

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Install Guide

1. Find a permanent +12V supply voltage.
I found a handy one at the terminal block behind the glove box and tapped into the wire.

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2. Tap into the Lock and Unlock wires on the CLCU loom
Refer to the table above for wire colours and functions.
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Any of the Lock/Unlock wires (pins 6, 7, 8 or 9) can be used to Lock or Unlock the doors, fuel door and boot.

In this photo, I have tapped into the UNLOCK wire for the doors and the LOCK wire for the boot.
Why?
I originally tapped into both wires for the boot (you can see the black strip on the YL/BK wire to the right), but I fried the internal UNLOCK relay on the CLCU with a mistaken wiring configuration before I worked out the correct wiring diagram of the stupid instructions. ](*,)
The boot now remotely LOCKS correctly, but I need to use the key to unlock it. A replacement CLCU is on my list.

Relays
Wire up your relays to convert the 12V trigger polarity to GROUND.
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Indicator Flashers
Locate and tap into your Indicator Wires.

I used the wiring loom under the steering column because it was easy for me to get to now and in the future.
Pass the indicator wires from the remote unit over the centre console to connect to the indicator wires.
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In this picture, the BU/RD and BU/BK wires on the left are our target.
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Mount your hardware
The plastic CLCU shroud is the ideal location to mount your new hardware.

• There is plenty of room behind the shroud
• It keeps all your wiring nice and short
• It keeps all your Central Locking hardware in the one location for future troubleshooting

Mount the relays to the bottom of the plastic shroud for the CLCU.
In these photos, I’ve accidentally installed the screws in the wrong direction (back-to-front). :roll:

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Mount the Remote Control box to the side of the shroud.

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Tidy up your cabling and mount it all back together.
Here you can see:
• The red 12V wire running overhead to the left
• The single GROUND mounted wire to the L-Bracket screw at the top.
(Ignore the screws poking out in the wrong direction)

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Optional Add-Ons:
I installed a pair of Viper 535T Window Automation Modules as part of this same project.
(Separate write-up)

Those units were mounted inside the HandBrake housing, so I ran the Window Close and Trunk Trigger wires from the Remote Central Locking box along the transmission tunnel.

These Window Automation Modules allow me to:
• Close the windows and sunroof when the car is remotely locked.
• Vent or Fully Open the front windows via the Boot Release trigger by holding down the UNLOCK button on the remote for 2 secs.

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Before Cleanup, Oh my…
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Pro Tip: Tapping into wires
Avoid using vampire taps or T-taps!
You *WILL* have one fail at some point which will force you to rip through your system to find the issue.

The method below will give you a better, stronger connection that will never fail.
  1. Strip the wire at the point you want to make a join.
  2. Poke a hole in the wires. A multi-meter probe works well.
  3. Make a short “stand-off” wire from the same wire as you will be joining. Use insulated female terminals to aid installation, removal and to avoid any accidental short-circuits.
  4. Expose ~2cm of bare wire, twist into a point.
  5. Insert the stand-off wire into the hole of the main wire and wrap the tail around the exposed wire.
  6. Optionally solder the joint, but it’s not necessary.
  7. Insulate with electrical tape.
  8. Label your wires!
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Attachments
A formatted PDF of these instructions is attached here for posterity.
04/1986 635csi Euro spec
Australian Delivered, RHD
Pod
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Re: Remote Central Locking, Keyless Entry Upgrade (86 BMW e24)

Post by Pod »

A great 'how to' posting - well done and thank you. Personally, I like the deadlock facility which I presume this locking system cannot utilise?
TimU
Posts: 280
Joined: Tue Dec 14, 2021 2:16 am
Location: Sydney

Re: Remote Central Locking, Keyless Entry Upgrade (86 BMW e24)

Post by TimU »

Hi Pod, sorry I missed your earlier reply.

Correct, the deadlock feature is 100% mechanical and cannot be triggered by the central locking system - remote or otherwise.

Deadlock requires a manual turn of the key in the lock and electrically disconnects the central locking system to disable its function.

I'm actually not keen on the deadlock system. It doesn't provide any greater security than the standard lock and causes all sorts of problems if it malfunctions.
04/1986 635csi Euro spec
Australian Delivered, RHD
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