1. Is there a single lead to instrument panel for overdrive light? Since
I
installed a tach the "5" light no longer comes on.
In the 86, yes. A yellow wire comes from the relay socket, changes to an
orange wire and enters the instrument cluster via the round multi-pin
connector on the rear of the cluster.
2. Where is the overdrive solenoid specifically located and does it have
any distinguishing markings? Is it an easy DIY replacement project?
On the Left side of the Overdrive behind the trans with two wires sticking
out.
DIY with a special wrench that allows clearance between the body tunnel and
the side of the Overdrive unit.
But why replace the solenoid? Was the overdrive working before you
installed the tach? If so, then your problem is with something that
happened when you had the cluster out to install the tach.
If it was not working prior to the tach install, something else is most
likely the problem. A blown or corroded fuse, a bad 4th gear switch on the
trans, loose or dirty terminals.
Where your problem with the non working OD depends upon how the dash light
reacted to the button on the shifter.
If the dash light came on with the push of the button, and no OD,
concentrate on the terminals and connections to the solenoid. The wires
have a tendency to break inside the wire right at the terminal crimp and not
separate at the insulation.
If no dash light with the button push, the fuse, or the 4th gear switch on
the top right side of the trans.
Duane
