I just have to relate the saga of the autopark system on my 1995 Winnie
Adventurer and see whether anyone can help.

The MH came with a Chevy P3/P30 chassis (which one depends on where you
read it; they're the same).  This chassis has a transmission
tailshaft-mounted drum parking brake.  The parking brake is held engaged
by a cable attached to a Very Large Spring (tm) under lots (and Lots,
and  LOTS!) of tension.  Counter to the spring is a small hydraulic
cylinder that releases the brake.  The cylinder is driven by a
standalone hydraulic pump backed by a small accumulator.  The pump, in
turn, is driven by a 50A relay that is picked when the engine is on, a
gear other than Park is selected, and the hydraulic system pressure is
below or drops below a preset value.  There is an accumulator release
valve that is actuated to release the cylinder and allow the Very Large
Spring to engage the parking brake.  All this stuff and a fluid
reservoir are neatly and "conveniently" packaged under the MH in a steel
box welded to the passenger side frame rail just aft of the transmission
(except, of course, for the cable and drum brake).

The relay failed; its contacts welded together and the pump would not
stop running until I unplugged it.  Happily, since the warning light
went out and I had no clue that the brake was not set, this happened on
level ground!

The local Chevy dealer is trying for the third time to find the right
part.  (They think it will be in tomorrow.  I'll be really happy if it
is.)  The relay is stamped with a Bosch part number, 0 332 002 192.  I
tried two local parts places but they can't order by Bosch part number
and they have no cross-reference.  I called GM customer service, where
they were ZERO help whatever.  (First, they tried to send me to
companies that do aftermarket modifications.  Then, it was, "Just bring
it to your dealer, sir.  They are trained to advise you on its repair
and can find the right part"  "Riiiight.  The vehicle does not move
without this part.  Do you know what it costs to tow a MH when the rear
wheels don't turn?"  Sigh.)  I tried a local truck center, where they
told me that Chevy sold this part of their business to  a company called
Workhorse, which now supports the P3/P30.  I called a Workhorse dealer,
where the parts guy was supposed to return my call this afternoon, and
did not.  I'll call Workhorse and Bosch next, I suppose.

Then I did web searches with combinations of P3, P30, autopark, and
"auto park."  This led me to posts to a Good Sam discussion board, which
confirmed that Workhorse now supported the P3/P30.  There was also
extensive discussion there about the auto park system.  Man, *I* was
lucky!  Most people have them fail when a hydraulic or electrical
failure engages the brake while they are driving!  At least the thing
failed--disengaged--at the last gas station on the way home and the rig
made it to the driveway...but, of course, the hydraulic pump was on
continuously for hours and it's designed for intermittent duty...so it
might be next.

I gotta say, this system is a real piece of work.  Once it's working, I
intend to disconnect it both mechanically and electrically.  This way, I
can hook it up if and when I ever sell the rig and demonstrate that it
works!  (There is a foot lever that operates the brake, too, so I won't
be without one.)

In the meantime...does anyone know the correct GM or Workhorse part
number for this relay, or have a source from which the Bosch part number
can be ordered?  That would be a HUGE help.  The MH has been hors de
combat for a month while the local dealer tries to find the part.  I
took apart the old relay, separated the contacts, and burnished them.  
It's working for now, but I can't trust it at this point.  At worst,
I'll use another 50A relay and change the connectors as needed, but I'd
be infinitely happier if I could replace it with a stock part.  This is
a really dumb problem to have.  The relay can't possibly cost over
$25...if only I could GET the durn thing!.

Also, I highly recommend that anyone owning a rig with this autopark
system investigate the failure modes and decide what, if anything, to do
with it on their own rigs.  This system has been around, with
variations, for some time.  Some earlier parking brakes are released
with the power steering pump rather than a separate hydraulic pump.  The
discussion on the Good Sam board indicates that for the style in my MH,
the switches, hydraulic valves, and relay tend to fail in modes that
unexpectedly engage the parking brake.  Last, I recommend that anyone
considering buying a MH with this system carefully consider whether they
want this...thing...attached to it.

JRE