Hi John,

First, you're reading the diagram page for early '86, just making
sure you know that.  Late '86 is on 97.99

At 05:16 PM 1/12/2013, John Reynolds wrote:
>OK - for rear heater - 1986 van.  Trying to figure out Bentley page
>97.82 Correct me anywhere I am wrong  Power from fuse #14 (20
>amp)  - feeds through 1.5mm black/yellow wire to dash switch with light.

Correct.

The light is completely separate - there's a callout tag to track 80
where you see it shown as one of the feeds from the panel dimmer.

>   From switch to 4-wire (T4a) rear connector under back seat. I can
> see that full power through yellow wire (max speed 3) - makes
> sensePartial power through low switch #1 via series resistor.
>OK questions - 1) Speed #2 Y/BK wire shows it going to nowhere.  It
>seems that it would have to go to the series resistor (to the
>mid-point of 2 resistors) - correct?  Why would it not be shown this way?

Drawing error.  They should have extended the heavy line and brought
the connection dot over to touch the thin line inside the resistor
outline.  Notice they made the same mistake for the front blower.  In
case you'd forgotten, heavy lines are wires and thin lines are
internal connections in a component or assembly.

>2) The under seat connector has 4 wires - the 3 shown to T4a and a
>brown. Yet the diagram does not show brown from/to T4a?  3) Brown
>from heater fan goes to ground #6 in diagram - which is listed
>as  under the rear seat.  I happened to pull the ECU today and there
>is a ground, but it appears to be used only by the ECU.  Does this
>ground run all way up front - perhaps through switch?  I can't
>imagine the running this wire under the van and around and back in
>to a single ground behind the ECU instead on a few inches in side
>the van or having the ground behind the heater instead,

Based on this I think you're looking at a late '86 where the ECU has
one of its grounds nearby instead of back in the engine room, and the
heater ground goes through T4a and is then called out to track 66
where it goes to ground 15 under the ignition coil.  97.99 tracks
148-9.  However in this case the power is called out to track 161 on fuse S12.

Yours,
David