1996 rear fan control

[deerefeed]

Does anyone have an owner's manual or something that explains the proper operation of the rear fan control? I think it's somehow interconnected to the front heating and A/C controls. I would just like to know how the front controls should be set when using the rear fan to clear the windows etc.

[Blue Bowtie]

Your assumption is correct. The rear (auxiliary) blower gets power via a yellow wire from the Aux Blower Relay. This relay is only enabled when the front (main) HVAC controls are active. Shutting off the heat or AC at the front should also shut off the rear blower. Turning on the front (main) blower to any position except "OFF" should enable the rear blower.

There are two options in this system. One if for a rear heat only with a fan control at the front. The other is for a rear heat and AC with a blower switch at the front and another at the left rear passenger console.

You can find some diagrams HERE and HERE

[LMP]

Originally Posted by deerefeed

....operation of the rear fan control? .

THe fan speed control itself is straight forward: that you have found by yourself. What you want to know is how to get heat or no heat, and direct air to floor or to top vents. Here is the plan:
If front heater control is set on A/C, VENT or MIX VENT/FLOOR, then the rear fan will deliver NO HEAT and air will be directed to the top vents.
IF front heater is set to HEAT(floor), DEF or HEAT/DEF, then the coolant valve to the rear will open and rear fan will blow warm air to the floor and to rear window vents.
Notice that the vacuum operated coolant valve can become defective with time. It can be stuck in open or closed position. Mine has fallen apart from corrosion.

[deerefeed]

Blue Bowtie, your links were not accessible to me without a library card.
LMP, that's the explanation I was looking for. I mostly want to clear the windows when there's a van load of people on a cold day and the windows are fogging up. What are the roof vents for? They vent forward and backward but don't seem to cool or heat.

[LMP]

Originally Posted by deerefeed

What are the roof vents for? They vent forward and backward but don't seem to cool or heat.

Indeed the roof vent will never deliver warm air.....except if a faulty coolant valve is blocked open. WHen the top mode applies, roof vents deliver air sucked from the rear floor at the same temperature it was ingested...except in a/c mode if and only if you had the rear a/c option...but this option is almost not existent in the Canadian edition...our climate explains.
So....roof vents just recirculate air taken from the rear floor. THe grille left of the left rear seat (2nd row, not 3rd) houses side by side both floor air inlet and warm air outlet.