The power locks don't work in my van. Pulling up the driver's door lock knob should cause all four other locks to unlock, and pushing it down should cause them to lock. It does nothing. Turning the key in the driver's door lock cylinder also has no effect on anything other than that door's lock mechanism, which works perfectly. It's as if the vehicle has no power locks at all. But every door has an actuator, and I know all but one of them work, so I know it had a functional power lock system at some point in the last 27 years. I've torn all the inner door panels off and spent a whole day probing every electrical component I could find with my multimeter and troubleshooting everything I could think of. It was a very frustrating day. Lack of proper schematics or documentation, and a total dearth of English info online about mid-90s Sambar door lock systems, makes this a serious Gordian knot. What I know so far: Driver's door "actuator" is actually a switch. It has two wires going to it. It either connects the two or doesn't. It actually has four pins, but since only two are connected, this is acting as a very basic SPST switch. Neither wire is grounded. Neither wire has voltage to ground. There is no voltage between the two wires. I'm 90% sure the problem lies in between this switch and what I can only assume would be the ECU, since there doesn't seem to be a dedicated module for the door locks. I think I should be able to detect voltage between at least one wire and ground, or that at least one wire is grounded. Passenger door and rear hatch actuators have three wires. One is ground. Applying 12 V to one pin makes the actuator move one way, applying 12 V to the other makes it move the other way. Sliding doors have two wires. Applying 12 V to one spring pin and ground to the other makes the actuator move one way; flipping the polarity makes it actuate the other way. I've confirmed: * Door lock fuse (15 A) is intact * Door lock fuse socket has 12 V across its terminals * Two wires going to the driver's door lock switch have no continuity between them and no voltage between them * Every actuator I've checked can be moved by applying 12 V with an external power supply, except... * Hatch actuator is dead, I managed to get it to actuate a couple of times but it appears to have internally disintegrated during that test and won't actuate anymore. It can be forced through its range of motion and you can feel/hear the insides grinding. It was previously stuck in the "unlocked" position. The problem seems to be between the driver's door lock switch and the ECU. Chasing the wires out of the door and back into the body of the vehicle is tricky, as they go through a grommet and into a cavity between the stamped steel sheet metal pieces above the accelerator pedal which is not accessible. I found what I assume is the ECU down there below the front right speaker, very close to where those wires go through a grommet and into an inaccessible cavity. So, why not remove the ECU? The wires probably go into it. Well, it appears you have to remove the whole dash, since the ECU is held on by at least 3 screws/nuts, only two of which can be easily removed, and the rest are hopelessly obscured by dash plastic. I'm not taking the whole dash apart without good reason. I'm apparently the only one who has any trouble with this, and at this point I'm about ready to give up hope for a realistic solution that will restore the system to the baseline functionality it had when it first left the factory. If I can't find a fix, I'll likely buy an aftermarket keyless entry kit and attempt to bypass the non-functional factory locking circuit in favor of something that actually f'ing works.