ZF Trans - Fixed - Low / No Power issue

[one_dusty_hoot]

!!O HAPPY DAYS!!,the neighbors can see the street, and...
best of all you're ROLLING AGAIN.

Quite a few of these ZF's in 87-89 FC's and later SP's also.
They seem to be a good transmission but when they are bad,
they are really BAD. With knowledge of them they may be an
easy to repair transmission, lot's of electrical. What scares
me is a $6,000 module that I've heard can go bad.

Glad you are up and running.
Bob Janes, 87FC35, Greenville, SC

--- In WanderlodgeForum@yahoogroups.com, "Alan"
wrote:
>
> Well, Thanks for help from all of you!! I finally got the coach
> rolling again. I think my neighbors are going to throw a block
party
> to celebrate it not being on the street any more.
>
> Here's what I fixed:
>
> 1. During this whole process I had the 12v wire in one of the
barrel
> connectors under the dash that had a meltdown. ...Not the wire,
but
> just inside the connector. I suspect it has probably had corrosion
> issues for a while and somehow this problem finished it off.
>
> 2. My 12v power going into the ZF ECU was out. Initially it was
> feeding 7.5v, but then it quit all together.
>
> 3. With 0v, coach would not start because it couldn't tell if it
was
> in gear or not.
>
> 4. I talked with Bennie at BB. We were never able to find where
the
> bosch relay is for this. My wiring is apparently differently than
> everyone elses. Bob Janes called me this afternoon and gave me a
> clue, however. Behind the access panel, behind the grill are two
> aluminum boxes, about 4"x4"x1". They are not easily accessed and
> not easily opened (but I'm going to open them later). Bob thought
> the relays may be inside these boxes and I think he may be right.
> Bennie at first thought they were flasher controllers. BUt there
are
> two many wires going in and I'm still missing a whole bunch of
bosch
> relays that should be there somewhere.
>
> 5. After more talks to Dan at ZF (again, very helpful) I cut the
two
> pink wires going INTO pin #19 on my ZF ECU. My ECU is behind a
kick
> panel, underneath the gear selectors.
>
> 6. I then connected the two wires going INTO pin #19 to a 12v
> source. Coach would still not start and no power was going to the
> gear selectors (they were not lit).
>
> 7. After talking again to Dan, we decided that one of the pink
wires
> may have been supplying 12v in and the other may have been taking
> 12v OUT to power gear selectors. At this point, I had cut those
> wires in two and what I thought was the supply side originally, was
> not connected to anything. (The other side of the cut went to the
> ECU and I had hooked 12v to it.)
>
> 8. I decided to send 12v down each of the pink wires the other
way.
> In the end, I needed to send power down both of them and here's
what
> I think.
> a. I think one of the wires supplied 12v to the ECU from a
> relay. ALSO connected to that relay MUST be a wire that was
> supposed to send power out for the neutral safety switch. It
needed
> power too. With that relay out, it was still not getting power
> until I hooked it up at the other end.
> b. The other wire sent power to the lights on the gear
> selectors. When I hooked it to 12v, they came on.
>
> So now, coach starts and transmission engages and operates smoothly
> (better than it was before as it's now getting 12v).
>
> Whew.. If any of that doesn't make sense, let me know. I want it
to
> be clearly documented for next poor guy with this problem.
>
> Thanks,
> Alan Johnson
> 972.333.4755
> 87FC35
>