e30 voltage drop needed for alarm

General E30 related discussions -
Please put technical questions in E30 Tech Help forum below

Moderator: martauto

Post Reply
User avatar
aarc
E30 Zone Newbie
E30 Zone Newbie
Posts: 228
Joined: Sun Oct 26, 2008 11:00 pm

Mon Mar 31, 2014 10:24 pm

Hi all in the process of installing a toad alarm Ive taken out the door switch to connect a voltage drop earth cable to activate the alarm on entry. There are two wires at the door switch I was wondering wich one cable should I attach the voltage drop cable to?? Please and thanks
Image
User avatar
aarc
E30 Zone Newbie
E30 Zone Newbie
Posts: 228
Joined: Sun Oct 26, 2008 11:00 pm

Tue Apr 01, 2014 9:45 am

Anyone ??
Image
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49358
Joined: Mon Jan 10, 2005 11:00 pm

Tue Apr 01, 2014 9:50 am

Doesn't matter in the slightest. Each pin switch is two identical switches.
User avatar
bdx
E30 Zone Newbie
E30 Zone Newbie
Posts: 197
Joined: Sat Mar 14, 2009 11:00 pm
Location: N. Ireland

Tue Apr 01, 2014 10:24 am

One wire is for interior light, other wire permits operation of electric windows with door open and ignition off.

For volt drop you want interior light.

Touch each wire in turn to earth, it will be the one that operates interior light.
User avatar
aarc
E30 Zone Newbie
E30 Zone Newbie
Posts: 228
Joined: Sun Oct 26, 2008 11:00 pm

Tue Apr 01, 2014 10:59 am

Ah excellent thanks for that mate cheers
Image
Speedtouch
Old Skooler
Old Skooler
Posts: 14020
Joined: Tue Feb 14, 2006 11:00 pm
Location: Canterbury

Tue Apr 01, 2014 11:00 am

As Brian says, they are two identical pin switches, that when the door is open, connect the cable to body earth. So, it shouldn't matter which you use.
///M aurice
ECU Upgrade EPROM Chips, £40 posted within the UK. Note these are not Zone chips.
viewtopic.php?f=6&t=279421
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49358
Joined: Mon Jan 10, 2005 11:00 pm

Tue Apr 01, 2014 2:05 pm

If I had to choose between the two, I'd go for the part that works the windows. The inductive load presented by the relay tends to keep the contacts on that switch cleaner than the resistive load of the interior lights on the other switch does, so is marginally more reliable.
User avatar
bdx
E30 Zone Newbie
E30 Zone Newbie
Posts: 197
Joined: Sat Mar 14, 2009 11:00 pm
Location: N. Ireland

Tue Apr 01, 2014 5:02 pm

Brianmoooore wrote:If I had to choose between the two, I'd go for the part that works the windows. The inductive load presented by the relay tends to keep the contacts on that switch cleaner than the resistive load of the interior lights on the other switch does, so is marginally more reliable.

Questionable...lets split hairs... here goes,

Personally I'd pick the interior lights wire, reasons being:-

1. Every time you open a door there is a visual reminder of the voltdrop circuit actually working, ie your interior light will illuminate.

How many times do we use the windows function on the pin switch ?
Not many
In fact it raises questions many times on this forum re windows not working when door is opened.

2. The resistive load of the lights would draw more current, therefore ensuring contacts on the pin switch wouldn't oxidise as easily.


Relay coils draw very little current and in some instances coil operating contacts are gold flashed for reliability at low currents.
User avatar
Brianmoooore
E30 Zone Team Member
E30 Zone Team Member
Posts: 49358
Joined: Mon Jan 10, 2005 11:00 pm

Tue Apr 01, 2014 7:34 pm

The relay coil is energised every time the door is opened, so whether or not the windows are actually moved when the door is open is irrelevant.
There are many threads on here regarding the windows not working when the door is open, but the fault in most cases is either fuse 28 is blown (usually cigarette lighter related) or the plastic button on the door that operates the pin switch has fallen off. It is rarely the relevant section of the pin switch itself that is at fault, but it is quite common for the interior light side of this switch to become intermittent.
User avatar
bdx
E30 Zone Newbie
E30 Zone Newbie
Posts: 197
Joined: Sat Mar 14, 2009 11:00 pm
Location: N. Ireland

Tue Apr 01, 2014 8:58 pm

Brianmoooore wrote:The relay coil is energised every time the door is opened, so whether or not the windows are actually moved when the door is open is irrelevant.

or the plastic button on the door that operates the pin switch has fallen off.
Based on the above statements, how do you ensure the pin switch is working correctly every time you exit the car ?
Does one listen for the door relay energising ?


By connecting it to the interior lighting side, every time you open a door there is a visual reminder of the voltdrop circuit actually working, ie your interior light will illuminate.
This will clearly indicate whether a pin switch has fallen off or not.

If a pin switch falls off, there is other issues....maintenance or poor installation.
Post Reply