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