In my previous post After Vacation Surprise I wrote about a mysterious ticking noise coming from the passenger foot well. This ticking noise either started occurring because the battery was drained, or the ticking noise drained the battery, which seems more likely. The previous owner claimed it needed reprogramming, but I have the suspicion that the alarm has aged its way to some sort of fault in the circuit which is causing the problems. In the end, the aftermarket alarm had to go.

I started by removing the bracket that holds the DME and the factory Porsche alarm. Lucky me, the aftermarket alarm, a Viper 690XV, was taped to the factory alarm. I detached the harnesses and started mapping out the wiring. I was pleasantly surprised that the wiring was not a big mess. Everything looked neatly organized. Most of the wires tapped into the factory wires.

 

There were a couple splices that appeared out of place as they utilized yellow caps. Each of the splices coupled three wires of the same color, usually two coming for the wire bundle, and one going to the Porsche factory alarm connector. This will need to be investigated in more detail to understand its purpose.

 

I used the Porsche Workshop Manual to decipher which wires from the Viper alarm went to which factory wires. To my relief, one of the “trigger” wires tapped into the hood latch sensor wire. This explained why the ticking would stop when the hood was open. Keep in mind that the factory alarm in the 968 is much more complex than in the 944. The alarm module used is the same one that is found on the 964 and the late model 928 (which we know can be an electrical nightmare). This alarm has two connectors and some 40 pins.

Each of the aftermarket to factory wire splices were covered with electrical tape, which suggests they were not t-jointed with a proper connector. Removal of the electrical tape uncovered a very unique but not ideal wire connection. What the installer did is locally remove the wire insulation of the factory wire, split the copper strands to create an eye hole. Then he took the aftermarket wire, inserted it into the eye hole, and then wrapped it around the factory wire. As a certain outspoken British automotive journalist would say, impressive but rubbish. When the electrical tape was wrapped around the wire, it did not fully seal the connection and corrosion or some sort of residue has started to form on the wire strands.

 

Four wires from the aftermarket alarm did not tap into any of the factory wires, but instead they were routed to the driver side of the car. Two output wires, one armed wire, and one siren wire. I traced the wires to driver side where for no reason, the wires were spliced and changed color. To make it more interesting, the four wires that were individually colored then spliced into 5 wires, where three of them are now orange. I can only guess that the current alarm spliced into an old alarm instead of routing new wiring. The orange wire in alarm systems is usually the trigger wire that energizes the relay that disables the ignition wire. Now that the output wire is colored as the trigger wire, it will be more difficult to understand the system. One of the trigger wires lead to the ignition disable relay. The other two orange wires, one output and one trigger, lead to the area of the rear hatch release button. One wire went to a relay that seemed to be hooked to the hatch release, the other wire went up into the dashboard where two new alarm boxes were located. More alarms?!?!

The two boxes were DEI 529T controllers. Some research educated me that these units are meant to control the windows up and down. To have both up and down control of the driver and passenger windows, two units were necessary. Each of these units had 9 wires, most of which went into the door. With that many wires going into the door, I will not be surprised to see a mess at the window switches. I removed the driver window switch cover and found the mess of wires as expected.

I decided to go ahead and remove the entire door panel before trying to sort out the wiring. This would have to be done in the future anyways, as I need to re-weld the door mounting brackets and fix the hinges. Removal of the door panel was fairly simple but there is an order of operations that needs to be maintained. First the door glove box needs to be removed, then the speakers, and then the brackets that mount the speakers but also hold the arm rest into the door itself. Once all those are removed, the fasteners that surround the panel need to be removed and the clips to the fwd and aft end of the door need to be popped off. At this point the door panel can be pulled up and slid out, as it is supported by the window seal lip and a metal bracket that is mounted to the door pull.  Pulling the door panel off, I discovered that the door, which as mentioned before came from another vehicle, used to be white.

I had a feeling this door would require some refurb work and my initial inspection confirmed my prediction. One of the issues I noticed when first driving the car, was a glass on metal knocking noise when the window was open. It appears the root cause of this issue is a detached sound proofing pad. The pad is supposed to be glued to the inside of the door skin and the window would rest against the pad when fully open. I also found a couple of the fastener heads to be rusted. This is because at one point in time, probably when the door was fitted to the car, a clean plastic sheet was glued to the door frame. This was probably done to replace the factory plastic sheet. The problem is that the plastic sheet that was installed sealed up all the crevices. This created a little greenhouse at the fasteners once a small bit of water got in. Luckily it appears to only be isolated to the fastener heads and should be an easy fix.

At this point, all the aftermarket alarm wires need to be removed and the factory wires need to be repaired.