No, the float switch started at the beginning of 85 model when the
pressure switch sensing was removed. The 85 wiring diagram page 97.65
shows the new reservoir float switch but mislabels it the parking brake
switch. The real parking brake switch is right next to it on the diagram
but is not labeled at all.

Bentley page 97.4 shows the various wiring diagram icons including
different switch types.

The parking brake switch uses only 1 wire and has a local ground via its
mounting screw, like the switch on current track 76 has.

The reservoir float switch uses 2 wires and one is a ground wire running
to the dash ground cluster, like the switch on current track 77 has.

Mark

David Beierl wrote:
>.....................
>
> On the '85 they seem to have done away with the pressure sensing and
> only activate for the hand brake.  I think this is unlikely and the
> wiring diagram is probably wrong.  I'm going to guess that they went
> to the float switch as below.
>
> Starting in '86 they changed over to a float switch on the reservoir,
> so in addition to the hand brake the light activates when fluid drops
> in the reservoir; but not for a pressure imbalance between the two
> brake systems.  To do the job thoroughly they need both.
>
> The OIL light is completely independent of any other system.
>
> Yours,
> David
>