I'd have to agree with you on the Haynes 940 book. Around here, it seemed to get the best recommendation amongst a poor field, but I'm not sure I've gotten a significant hint out of it yet. Hopefully some day I'll find a nugget; usually even one will make the $50 or so purchase price worthwhile!


With the help of your information, I believe that this is how it works:

The shift lock relay is engaged any time that the ignition is on, providing that the starter isn't cranking (as I think you pointed out). When the brake pedal is depressed, it closes the brake switch contact, and 12 volts is sent to the shift lock relay's switch contact. With this relay constantly engaged, its switch contact is already closed, so it passes the 12 volts on to the shift lock solenoid. Providing the transmission is in park, the microswitch grounds the other connection to the shift lock solenoid, energizing it, and allowing the shifter to be moved out of the Park position.


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David Armstrong - '86 240(350k km?), '93 940T(270k km), '89 240(parts source for others) near Toronto