How to:- Fitting a Cobra Alarm in a VW Baywindow FAQ

[chrisradioman]

I used to be a dealer for Cobra & let me tell you they are the best alarms on the market, there are other good ones too. Toad is good but we did have a couple of faulty ones returned. Clifford are awsome but very complicated & its easy to make a mistake. Cobras never go wrong & you can buy every part separate easily. You can't go wrong with them. I have chosen a 7928 this is a Cat 1 alarm with ultrasonic sensors & it is compact which means the alarm is built into the siren which has a back up battery built in.

The first thing to do is to find a suitable place for the siren. It is water tight so can be fitted anywhere. Its always best to keep away from heat & moisture though so I have fitted it on the LHS front next to the headlight bowl.

The next thing to do is start the wiring, there are three wires sticking out partway up the loom there is a good reason for this however it is not necessary for us to use all of them as my Bus does not have central locking The black wire I soldered a tag on & conected it to the other earths on the headlight bowl.

I pulled one of the transmitter cables through the loom to exit at the same place as the ones I mentioned earlier & these will go up the LHS A pillar.

Next I have loomed the cable up as far as the fuse box following the path of the original wires.

Next I carried on the looming letting the red (+30(+12V perminant)) wires exit behind the fuse box this will be connected latter.

Now the wires were loomed up to behind the instrument cluster, following the original wires.

Next I fitted the immobiliser unit, this should be mounted out of sight & fitted where it is hard to get too. As the top is off my dash I can see easily where to put it. I have chosen to screw it to the steering support bracket.

On the immobiliser all of the cables are black to make interference after installation almost imposible. all the cables have print on the end & once cut the unit is useless to anyone. I connected the wire with code printed on it to the green wire coming from the siren with code printed on that.

The next thing to do is connect up the two yellow wires these are the feeds to the indicators. These are green/black & white black on the VW (carefull you don't conct to the black white which looks similar) & can be found coming up from the steering column in a loom with lots of thick wires. These can be connected up either way around it doesn't matter.

The next thing to do is fit the LED, there are lots of places to fit this but I have chosen to use the blanking plug on the instrument panel.

_________________
http://www.vintagevwweddings.co.uk/contact.html

[chrisradioman]

Right lets carry on, I used a test light with one end grounded to look for a permanent 12V supply (+30) I found a thick yellow one above the fusebox. Note the Snake's wedding, I think most 30 year old VW's will look like this (or worse)

I spliced the red wire for the alarm into it by baring back the insulation wrapping the cable around it & soldering the joint. Don't use connectors or scotch locks or you'll get troble in the future.

Next I cut the newly installed red wire installed an in-line 16A fuse. Make sure you use a fuse or it could all end intears if the alarm ever goes faulty.

Next I soldered the Black wire from the LED to the White/black from the alarm.

Next I drilled a 16mm hole in the dash for the touch receptacle. I chose that position because there was a burn hole there so I thought I'd hide it otherwise I would have put it somewhere else. I didn't fit that dodgy switch below. That’s going when I get around to it:-

Out of the back of the touch receptor there are two cables, the yellow one needs to be connected to earth, I have chosen the multy connector on the back of the clocks.

The other wire is Red/Green, this is connected to the pink wire (don't ask me I didn't design the unit)

_________________
http://www.vintagevwweddings.co.uk/contact.html

[chrisradioman]

Right then lets continue. I checked at the loom coming up form the ignition switch for a +15 (ignition live) that stayed live whilst cranking & again there was a thick black one I cut this & turned on the ignition no dash lights (thats what I wanted)

I soldered to this one of the immobiliser black wires with "+15" written on it (double check before cutting, I always check twice, then read the cable as I am about to discard the end)

I double checked that the end I soldered to was still live with the ignition on then soldered one of the black wires with "2" printed on it to the same place.

I then followed the other end of the wire & pulled it out of the loom cutting out 20CM which I discarded, you have to cut off at least 10CM.

I soldered the other black wire marked "2" to this end this is one of the immobiliser cuts & I have no ignition now as a result.

Back to the immobiliser, there are 2 earth cables marked "-ve" I conected one behind the clocks to the multi connection:-

& one to the headlight bowl don't connect them both to the same place:-

While in this location I conected the blue/pink wire from the alarm to the door pin swich cable:-

I then conected the red wire from the LED I fitted earlier to the thick red wire in the inition harness, this is +30 (live at all times)

Then I checked for a starter circuit the black/red thick cable becomes live only when cranking, so this is the one, I cut this & soldered one of the black immobiliser cables marked "1" to it:-

Next I cut out 20CM off the cable & soldered the other black cable marked "1" to the other end of the cut, this is the other immobiliser cut now I have no starter:-

This is the bit I cut out:-

Now the car wont start & I have no ignition, but when I disarm the immobiliser they are reconected internally in the immobiliser & then it will work. There is one last wire on the immobiliser marked "+15" don't connect to the same place as the other one, I conected this to the Green/red wire coming from the alarm wiring, this is the ignition sense wire & its important not to conect this to the car wiring

_________________
http://www.vintagevwweddings.co.uk/contact.html

[chrisradioman]

Now the hard bit fishing the cable down the A pillars, I always use 6 core telephone cable as it is stiff, my roof lining is out so it makes life easier.

Push the cable down the hole in the A-pillar:-

Pull it out of the bottom, it’s not a nice job it can be frustrating & I found it easier to remove the Door pin switch.

Use this cable to pull a thinner one up:-

Then pull the ultrasonic senor cable down, make sure the tape is not too thick & don't force it, you'll break it, also make sure you get the right colour one down. I have used Red on the RHS but it doesn't mater:-

At the same time pull in a blue cable for the rear door switch your going to fit later, solder this to the blue wire that comes from the alarm.:-

Plug in the matching plug & socket:-

Drill the bracket attached to the sensor with a 3.5 mm drill bit:-

Remove one of the press studs & fit this to the bracket as pictured:-

Fit the press stud back where it was sandwiching the sensor in place:-

The other side of the bus solder the blue wire with the black sleeve to a piece of blue wire (it doesn't have to be blue but I like blue!)

Repeat the fishing process on the LHS not forgetting to plug in the white pair:-

Then fit the other sensor:-

At the B-pillar where the sliding door closes there is a plastic grommet remove this & you can fit a door sensor to it ( there is one in the kit) the blue wire then has to be fished down here:-

Anyway the alarm now works as it should any other wires left over with exeption of the Blue ones should now be insulated & hidden in the loom, these are for various optional extras, window closure modules, boot release, extra sirens, extra sensors or central locking, you may want to upgrade later so remember where you hid them..

That’s it for now the only things left are to get the blue wires to the sliding door for a pin switch, to the tailgate & I'm also going to protect the engine lid & finally tidy up the snakes wedding undert the dashboard. I'll update you all later.
_________________
http://www.vintagevwweddings.co.uk/contact.html

[chrisradioman]

Right today whilst doing other jobs I dropped one of the blue Cables down the RHS B-Pillar & fished it out where VW very thoughtfully left a hole:-

Then I fitted a crimp on Spade connector & pluged it in to a door pin switch, my finger is there to hold it on as I hadn't screwed it in place at this point.

_________________
http://www.vintagevwweddings.co.uk/contact.html

[1975 Kombi]

I have to replace the wire that went down the A pillar. For the sliding door. Man the wire keeps hitting something at the bend with the roof and the side of the bus. I am going from the roof light down the channel and then down the side pillar all in one shot. The phone line might do the trick. I was trying to find a snake somewhere but that might do it. The wire hits and folds.
_________________
Brett

“He’s decieving you boy! Reach into his pocket and take what he’s got.” Mr. Crabbs.

75 Westy auto
03 Jetta TDI
71 SB
74 Westy
Licensed pilot (single engine land VFR)
--
Rust In Pieces: 72 Bug, 73 Bug, 81 Rabbit LS D 2D, 83 Rabbit D 2D, 84 Jetta TD GL, 85 Jetta D, 68 Z28 RS 302, 91 Passat 16v

[chrisradioman]

Good luck with it M8, it can be tricky going from the light. You mean the B-pillar the A-pillar is the one with the Windscreen. At the top of the B-pillar there is a hole about the same diameter as that of your thumb so the wire has to get in the middle of it otherwise it will just hit the inner roof section. It might be better to pull the roof lining down at that corner.
_________________
http://www.vintagevwweddings.co.uk/contact.html

[1975 Kombi]

Ya B pillar and I do have the roof liner down. The vibration from the bus cut the wire at the bend. The roof light would not come on so I checked the button at the door and it came out with half the wire.
_________________
Brett

“He’s decieving you boy! Reach into his pocket and take what he’s got.” Mr. Crabbs.

75 Westy auto
03 Jetta TDI
71 SB
74 Westy
Licensed pilot (single engine land VFR)
--
Rust In Pieces: 72 Bug, 73 Bug, 81 Rabbit LS D 2D, 83 Rabbit D 2D, 84 Jetta TD GL, 85 Jetta D, 68 Z28 RS 302, 91 Passat 16v

[chrisradioman]

If you poke your finger in you will feel the hole I'm talking about. Use some stiff wire then use that to pull in the new wire solder it to the old one & put some sleaving on it where it goes through the hole to avoid it happening again.
_________________
http://www.vintagevwweddings.co.uk/contact.html

[chrisradioman]