In an attempt to fix my reverse lights, I managed to completely break
the neutral safety switch on my AW4 transmission. The AW4 Neutral Safety
Switch, also known as the Transmission Range Sensor, defaults to "D"
from what I can tell, which would mean that if this switch breaks, the
car will not start! This is the exact problem I had.
A lot of people suggested rebuilding it but I broke the switch completely--it
wasn't salvagable. Instead, I did something that was much easier and
took about three minutes. I cut the wiring harness near the switch and
pulled the wiring up through the engine bay and connected the #7 and
#8 wires as described below. This effectively tells your Jeep that you
are in neutral all the time. Beware that your Jeep will start in D,
R, 3, 2/1 now! I don't really see that this should be a problem but
it is recommended that you do not start the vehicle still, unless in
P or N.
From some research I have done, the car does not use this Neutral Safety
Switch for anything except for a) allowing you to start the ignition
and b) triggering the reverse lights. As a result, "hot wiring"
the switch as described should not hurt the vehicle's operation. The
only problem I have run into so far is that this throws a code. I am
still working on figuring out how to jump the wires in order t moake
this go away.
Neutral Safety Switch Wiring Diagram aka AW4 Neutral Safety Switch Schematics