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gshaw

Posted 16/3/2006 3:43 PM (#120984)
Subject: Tony's Electrical bits (see CONTENTS in first thread)

MP Admin

Posts: 8747
5000

Location: Greater London \ Essex

CONTENTS (so far)

Alarm
Central locking (inc. Maplin motor wiring)
3As to 5As conversion
Electric Windows
LED Indicators

Photos/Schematics

First Schematic gives details of

C_locking
Radio
Windows - but see Windowssection for full detals
Alarm - but see 3As to 5As conversion for full details

1.0 ALARM SENSITIVITY

I found that to lock/unlock (arm/disarm) my Ascot R100 etc you have to stand very
(very) near to the car to use the transponder (fob). Even then a second blip may
have been required.

1.1 5AS ALARM

On investigation it was found that on the 5AS alarm, the aerial was buried in the
wiring harness to the alarm. The length was only approx 110mm. Colour White/Yellow.

This is very bad RF practise. You don’t bury an aerial in effectively a copper shroud.

So I removed this wire and replaced it with one 346mm long. This is half wave length
for the nominal transmit frequency of 433MHz. I dressed the wire behind the heater
and cassette box held in place by tie wraps and to stop snagging etc etc.

The length does not have to be that accurate – say +/-10mm.

With this little modification, I can now lock/unlock (arm/disarm) the car with a range
of about 20ft and can be done through my lounge window.

1.2 3AS ALARM

With respect to the 3AS alarm – this has a coaxial connection using coaxial cable.
Importantly this cable is not buried in the harness. The length of this cable is just
over 346mm so need not be modified. Again for slightly better response it can be dressed,
like the 5AS Ae behind the heater and cassette box.

1.3 SELF DIAGNOSTICS -- 5AS ALARM -- FROM THE ROVER RAVE MANUALS

The anti-theft alarm ECU contains a self diagnostic feature which tests and confirms
inputs to the ECU. When in this mode, normal functionality of the ECU is suspended.

The following procedure must be followed to enter self diagnostic mode. The procedure
must be completed within 5 seconds.

• With driver’s door closed, press the sill button down
• Move the ignition switch to the on, then off and then on position
• Lift the driver’s door sill button.

Successful entry to the self diagnostic mode is confirmed by a brief operation of the
vehicle horn. The engine will become immobilised and the MFU will emit a two tone sound
to confirm that the engine is immobilised. Failure to enter the self diagnostic mode
indicates that the ECU is not receiving sill up or down or ignition switch input.
A spare vehicle key will be required to test the key barrel switches.

The following inputs can be tested and confirmation of receipt of the input is confirmed
by a brief flash of the LED in the instrument pack...

Sill button
Press the driver’s door sill button down, the ECU will immediately move the sill
button up to unlock the doors.

Driver’s door open
Open the driver’s door to activate the switch on the ’A’ post.

Passenger and rear doors
Open the passenger and rear doors to activate the switch on the ’A’
post and the ’B/C’ posts.

Bonnet open
Open the bonnet to activate the bonnet open switch on the bulkhead.

Tail door open switch
Open the tail door to activate the boot open switch in the tail door
latch.

Key barrel switches
Operate the driver’s door key barrel switch using the spare key.

Self diagnostic mode is exited by moving the ignition switch to the off position.

1.4 PICS

Apart from pic. of 5AS alarm, I have also included trace of transponder response taken
on a Spectrum Analyser at work. This was my fob. This is basically amplitude shift keying
i.e. power on power off to produce the code. (Well --- someone maybe “vaguely interested”
in this one!!)

2.0 CENTRAL LOCKING CHECKS

The standard Rover door actuators (made by Rockwell) are known to be problematic and are
expensive to replace. Maplins do a much cheaper version.

WIRING FOR ROVER CONNECTOR TO MAPLIN MOTORS

When replacing Rover motors for Maplin ones you'll need to solder the original c\l connector onto the Maplin item, wiring is as follows...

DRIVER
Pink/purple ---- white
Purple-----------green
Orange----------- blue
Orange/purple----brown
Black------------black

PASS
Pink--------green
Orange------blue

The main problem is with the driver’s door actuator. This has two sensing wires back to the alarm. If the
sensing is not working and the alarm does not have that earth signal from the door actuator
it can put the alarm into undocumented (funny) modes and hence difficult to arm/disarm the alarm.
The LED also does not flash correctly. I had one system where the central locking started
pulsing – off - on - off - on etc.

Firstly disconnect the driver’s central locking door harness by the right side of the fuse box. (Quite awkward to get at.)

Referring to my drawing, the five wires in that connector are:-

Orange ---> pos/neg power to actuator from alarm
Pink ---> pos/neg power to actuator from alarm
Orange/Purple ---> sensing back to the alarm
Pink/Purple ---> sensing back to the alarm
Black ---> earth used by the sensing

On the female connector (car side); with a DMM, check that the black earth wire does go to earth. If a poor
earth then check connection under bonnet at earth bonding point by washer bottle. The earth
wire is taken to this point. If that is OK then :-

Connect an earth wire to the Pink/Purple lead. If the earth is good in that harness then a
simple 5cm jumper lead can be used to that black earth wire.

Sit in the car and close the door.

Now activate the alarm using the fob. The passenger door and boot actuators should work and
the alarm should correctly function arm/disarm etc and the LED should flash correctly. If
all this is ok then it means that the driver’s door actuator has gone u/s.

If there are still problems with the central locking then disconnect, in turn, the passenger
door actuator and the boot actuator and try again with all doors closed. At least now the
alarm should correctly function.

If the driver’s door actuator is faulty, until you get a new one, leave that shorting wire in
place. It will do no harm. On cars with no central locking where that Pink/Purple wire goes
into the alarm a black earth wire is permanently fitted in lieu. Again see my drawing.

3.0 3AS TO 5AS ALARM CONVERSION

This schematic details the conversion from 3AS to 5AS alarm. The internal picture of the
alarm shows how to wire the relay into the alarm for the horn circuit.

PHOTOS - SCHEMATICS

Click the link below the thumbnail to see a h-res image.

Click for hi-res version

tonyb

Posted 16/5/2006 11:55 AM (#143304 - in reply to #120984)
Subject: RE: Tony's 3AS to 5AS Guide and Remote Central Locking Tweaks

Electrical genius

Posts: 1310
1000

Location: East Devon

THIS SCHEMATIC DETAILS THE WIRING CONNECTIONS FOR ELECTRIC WINDOWS

(WindowElec_CD_01.gif)

Attachments
----------------

WindowElec_CD_01.gif (97KB - 361 downloads)

tonyb

Posted 4/11/2006 12:23 PM (#200938 - in reply to #120984)
Subject: RE: Tony's 3AS to 5AS Guide and Remote Central Locking Tweaks

Electrical genius

Posts: 1310
1000

Location: East Devon

LED FLASHING INDICATORS

If LED bulbs are fitted then the current drawn by them is much lower than conventional
bulbs. If the all bulbs are changed ie front, back and side the current is reduced from approx
4Amps to about 200mAmps, so the flasher unit now thinks there is a blown bulb and the flash rate
is doubled.

This problem is very easy to overcome.

In the flasher unit there is an IC that monitors the current via a shunt resistor in series with the
relay. There is a finite voltage drop across that resistor that is compared with a reference voltage
in the IC. If that voltage drop is too low, due to lower current being drawn due to a blown bulb
then the flash rate is doubled.

It looks like there are two variations to this flasher relay unit. Pics shown. One has a link from
the 12V power to the relay and the other has a strap direct to the relay.

Because the value of that resistor is very very low ( 30mOhms) it is actually the wire link in one
and the strap in the other type.

So how to overcome the problem.

A good voltage drop is wanted so why not 0V / ground.

To achieve this just cut the track between pin 7 of the IC and relay and leave it floating. This
works. But it is not very good practise to leave IC pins unterminated / floating so I have tied
mine to the 0V ground with a 4k7Ohm resistor. Any value will do between 1kOhm and
10kOhm. As can be seen I got mine direct from Farnell but Maplins would do a similar. Without
checking I think it is +/- 1% and ½ watt. But tolerance is not that important or power rating.
You may be able to get one from your local radio/TV shop.

PS I have not fitted LED bulbs but just thought I would have a look at the problem.

PS PS Please do not add comments to this thread as this sticky is getting rather messy now.

tony