Date:         Sat, 12 Jan 2013 14:16:04 -0800
Reply-To:     John Reynolds <transporterjr@YAHOO.COM>
Sender:       Vanagon Mailing List <vanagon@gerry.vanagon.com>
From:         John Reynolds <transporterjr@YAHOO.COM>
Subject:      Help me read a wiring diagram
Content-Type: text/plain; charset=iso-8859-1

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.  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?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,
Just trying to understand this better and get better at reading these wiring diagrams.
Happy trails,John