CENTRAL DOOR LOCKS ->93 900 9000

First check that the fuse for the central locks is good, fuse 24 on 900 and fuse 16 on 9000s.

The ECU (relay) is triggered by a switch in the driver's door. It has three wires, green red and black on a 9000 and differing colors on a 900. The easiest way to check this on a 900 is to find the three pin connector in front of the driver's door in the engine compartment with brown and white, blue,and brown wires on one side and green and white, yellow and black on the other. On a 9000, the wires run through a 22 pin connector at the door. The easiest way to check them is at the ECU.

The ECU on a 900 is on the passenger side on top of the floor ventilation duct, secured by a bracket. Remove the rightmost screw holding the vent up, lower the vent and pop off the bracket with the ECU. On a 9000, the ECU is a bit harder to get to, held to a plate on the driver's side under the dash by either a clip or screws from above. It is easiest to drop the whole plate to get to this ECU on a 9000.

On a 900, unplug the three pin connector with the above wire colors and use the side going into the car (not coming from the door) and jump the green/white wire to the black wire. This should lock the doors. Jumping the yellow wire to the black wire should unlock the doors. The black wire should be grounded all the time. It runs to pin 3 of the ECU and then to ground at the center console, at the hand brake lever. If the locks work here, check the driver's door switch by using the other end of the connector at the front of the door, at the hinge, in the engine compartment as follows; when holding the key to the lock position, check for continuity between the brown and white and the brown wire, when holding it to unlock, check for continuity between the blue wire and the brown wire. In the neutral position, there should be no continuity between any of the pins.

On a 9000, go to the ECU and jump pin 2 (green wire) to ground pin 3 (black wire). The ground point for this pin is at the left front speaker with a group of grounds there. The doors should lock when pin 2 is grounded. Jump pin 1 (red wire) to pin 3, doors should unlock. If so, check the signal from the driver's door switch by unplugging the ECU and checking for continuity between the green wire (pin 2) and the black wire (pin 3) while holding the key to lock. Check for continuity from the red wire (pin 1) to the black wire (pin 3) when holding the key to unlock. Make sure none of these pins have continuity when the key is in the neutral position.

If the driver's door inputs check good and the doors don't lock and unlock, check that the ECU is getting power in at its pin 4 (9000 blue wire, 900 green wire). Check that it has a ground at its pin 3 (black wire). The ECU should send a brief signal out its pin 7 (9000 brown and white wires) (900 violet wires) and supply a ground at its pin 8 (9000 violet wires) (900 brown and white wires) These are reversed between cars and to avoid confusion, just connect a test light across these terminals and work the key in the drivers door. You should see the test light light briefly when turning the key either to lock or unlock. If this happens, then the motors in the doors are bad.

If only one door doesn't work and the others do, then the problem is in that door, either in the wiring to it or in its motor. All the door motors receive a signal from the same pins out of the ECU. Remove that door panel, unplug the connector to the lock motor and connect your test light across the harness side connector. Turn the key and watch for the light to light. if it does, the motor is bad, If not, trace the wiring for that door back to the ECU and repair the problem.

If the fuse for the central locks is blowing when locking and unlocking the doors, use a 5A higher rated fuse. Usually, the responsible motor will not work, or will be slow and you can pin point it. If not, unplug each motor one at a time and test to see which one causes the fuse to blow. Replace the motor that the fuse doesn't blow on when it is unplugged. Remember you also may have a hatch or trunk motor and a gas door motor.

On hatch or trunk motors that work, but don't lock or unlock the lock, the motor may be kicking the linkage so hard that it kicks back to where it was. Saab has a fix for these. Install an appropriate size screw with a washer into the pivot for the linkage and tighten it just enough to put a little tension on the linkage and keep the motor from kicking back.

It is not a good idea to test the actual motors by removing them and connecting 12V and ground directly to their pins. The motors only receive a very brief pulse from the ECU to work and straight wiring voltage to them could burn them up.

If you get into the door panels, be sure you tighten all the nuts and bolts there as well as lubricate your window regulators and tracks, and door latches while the panel is off. If the vapor barrier is in bad shape, or you trash it, make a good barrier from 3 mm plastic (like painter's drop cloth stuff) and attach it by using spray adhesive to the door. This helps keep the door panel nice and the sound levels down.