Hello all, I have a specific wiring question about the AC Vacuum Kicker Solenoid/Idle Stop Switch that compensates for the extra load at idle when the AC compressor is running. The wiring diagram in the Service Manual calls that unit the "Idle Stop Switch (On Carburetor)". The emissions sticker under the hood calls it the "Vacuum Kicker Solenoid". As the last name implies, it has both a vacuum and an electrical aspect. The electrical diagram in the Service Manual only shows one wire connected to it, which is grounded when the foot is off the accelerator pedal. However, the actual component that came stock on this 1987 V6 California truck has two wires connected to it. The wire that is grounded at idle goes to the 7-pin of Connector #1 on the Spark Control Computer. The second wire on the actual component is not shown in the wiring diagram. I enclosed a photo of the wiring diagram of this component in the Service Manual, and two photos of the actual component in the truck, with the second mystery wire coiled up. It is the red wire. It was originally black with a red tracer.

Can anyone clear up this mystery for me?

Thanks,
Jack


Idle Stop Switch - lower right corner

AC Vacuum Kicker Solenoid/Idle Stop Switch

AC Vacuum Kicker Solenoid/Idle Stop Switch

 

I just looked at the wiring for the same component on the 2.2L L4. It has two wires, the idle stop switch wire which is grounded when at idle, and another wire that goes through a solenoid coil in the AC Vacuum Kicker Solenoid to ground. This wire is connected to the + terminal of the Ignition Coil, a dark green wire at the Alternator, the Choke Heater Switch, the Purge Solenoid, the ETC(?) Solenoid, the Diagnostic Connector, the Part Throttle Unlock Relay, Fuse #13 (?) and the Voltage Regulator. All of these components are connected together to the #2 pin of Connector #1 of the Spark Control Computer (whew). From all this I deduce, correctly, I think, that the computer is supplying +12 volts to all these components when the ignition switch is turned on. The ignition coil needs to be constantly supplied with +12 volts and it is grounded as needed by the Spark Control Computer.

Sucks that the Service Manual is not correct, but my work as a carpenter over the decades has convinced me that those who draw lines for a living also invariably make mistakes.

Jack