Installed Remote Keyless Entry today! The '80 came with no central locking or wiring for it at all - all manual. And the passenger side was always stuck - had to unlock from the inside, which becomes pretty annoying with a baby to load when you're in a hurry. So decided on central locking with keyless entry. Wanted to keep it all Saab - so I salvaged a central locking setup from a '93 hatch and an alarm system from various '92+ convertibles. Installation was pretty straight forward:
Parts Needed: Central locking computer, two PASSENGER SIDE door lock actuators, one trunk lock actuator, alarm remote and brain WITH MATCHING CHIPS, alarm and central locking wiring harness/connectors from a '92+ convertible (91 can possibly be used, but needs some modification), alarm siren, alarm hood switch, alarm deactivation switch, 2 relay ports that come as part of the wiring harness, lots of different colored wiring.
Process: I needed to drill out two holes in each door to bolt down the door lock actuators. I measured the hole locations on a '92 convertible and copied it.
Once drilled, I attached the actuator arm to the hook at the bottom of the door lock pull (existing - you just have to pop the hook out and slide the actuator arm through and pop it back into place) - just hard to reach. Then bolted down the actuator and ran the wires through the door and into the cabin.
The trunk was more complicated. Had to fashion a mounting bracket for the actuator out of some metal strapping, then popped off the lock arm and hooked in the actuator arm - similar to the door actuators, then ran the wires through the hatch, into the car, and down along the door sill, and under the dash to the location where it all hooks up the central locking computer.
Using the wiring diagram on page 371-39 of the Bentley Manual, I wired the central lock computer. These are all the same for any c900 with central locking as far as I can tell - only the wiring harness itself changed. With all this wired in the same way as the '92+ convertibles, you can no longer activate central locking by unlocking the drivers side door. It has to be by the remote.
Next, wired the alarm. Before anything, I went through the entire diagram and identified the stuff I really needed and stuff I didn't need. I wasn't too concerned with most of the fancy alarm components, so I opted out of the starter lockout (the larger of the two relays), the dash LED, cabin lock/unlock switch, glass-break sensor, and interior lighting components. I did decide to install the corner lights blinking relay, hood switch, siren, and alarm deactivation button. I just wired in the stuff I wanted, and taped off the stuff I didn't. For power, I connected to the always-live memory power wire that goes into the stereo (so I didn't have to run that through the firewall). The deactivation switch, I mounted in the center console under the interior light switch. The corner light relay I wired to the emergency flashers switch. Only ran two wires through the firewall - one for the siren and one for the hood switch. I ran it all under the dash above the HVAC duct above the pass-side footwell. It stuffed right in with plenty of space.
Turned out really sweet! Now the remote locks and unlocks both doors and the hatch, complete with the chirp and flashing hazards.
