87 control module

[Nordren]

i have the good ol' push button for 4x4, but i cant remember entirely if its powered by the ECU or the button itself (gets power from the ecu but it operates itself) believe it does. think i found the someone talking about it on here a while ago but i cant seem to find the thread again. im trying to do an engine swap (2.9 to 4.0) due to availability was checking my options. THANKS!

 

[canyoncritter]

http://www.therangerstation.com/tech_library/4wd_control_module.html

the 4wd has a computer and power source of its own. thinking of swaping a 4.0 and harnessfrom a 2wd truck?

 

[ElectraRider]

there is a 4x4 control module self-test, this is out of my truck shop manual for 1989
compact trucks
the electronic control module has a diagnostic capability of its own circuitry. the self-test
is as follows:
1. remove the five-wire connector and the eight-wire connector from the electronic
control module.
2.turn the ignition switch to the "run" position.
3. activate the self-test switch and note the result: a flashing indicator lamp
(approximately one flash per second) indicates that the control module is functioning
properly. a steady light indicates that the control module is inoperative and must be
replaced.
there is a white lever that is pulled lightly and a red led on the side of the module.
hope this helps.