so i removed the alarm control on my 1989 964 c4 and found bottom portion of circuit board all full of corrosion from water seeping in.I personally think it is just a bad design flaw i think it's a result of water running down the wires and entering the control unit itself.it probably could have been avoided if they had just mounted the box connector down instead of sidways so water dripped down instead of into the box. what a shame!

 

Get in touch with Steve W. at RennsportSystems; he will send you a can of good Deutsche "spritzenstoffedasmanspritzaufdinge". It is a superb contact cleaner, corrosion remover and protectant.

If he insists I use it, I use it and nothing else.

 

That looks nasty. Looks like you may have found your failing to start root cause. Congrats!

 

You also need to find out how the water is getting in to "run down the wires", mine stays dry in that area
maybe your hood gasket needs replacing?

 

well itried cleaning it off as best i can with electrical contact cleaner,silicones around outer edge of case and put dieclectric grease in the connector front and back to try and prevent further water from getting in.I also tried bypassing pin 7 and 8 or (61) and A on the case cover pin designation.Now by jumping what i mean is i plugged the connector back in and on the 2 wires going to those pins i soldered a wire bridging them.Problem now is car starts but i cannot lock my doors with key.

Have i done the procedure wrong for jumping the immobilizer? I need somebody to chime in i know it"s not a topic anyone wants to discuss for the reason of preventing our cars from being stolen so even if you pm on what pins i should be jumping here is the part #928.637.104.05 on a 1989 964 c4.Tried searching there is a lot of threads and posts but no clear answer as to how to do it.