I've got everything for an early fan if needed.

Jim

On Sat, Aug 22, 2015 at 3:31 PM Dennis Haynes <d23haynes57@hotmail.com>
wrote:

> The wiring and operation of the 90 is drastically different than in the
> 84. The fan motor is much larger, one speed using a resistor to provide
> lower speeds and multiple relays for control. Also depending on variations
> some will have the cooling fan low speed operation effected or even
> disabled if the AC wiring is hacked. Here is a brief summary of expected
> operation.
>
> Engine cooling
> When radiator fan switch calls for low speed cooling the switch directly
> supplies power from the fuse block through the resistor to the motor.
> When same switch calls for high speed there is a relay above the fuse box.
> This relay brings power directly from the battery (own wire) through a
> fusible link directly to the fan motor. A failed fuse for the control and
> low speed disables both these systems.
>
> To support the Air conditioner
> When the compressor is on the fan runs at a low speed energized from a
> relay in the AC system. This also depends on the fan resistor.
> If system (AC) high side pressure increases due to insufficient cooling a
> pressure switch operates a relay in the fuse box to increase the radiator
> fan speed. Basically the other side of the fan resistor is placed in
> parallel increasing current flow and thus fan speed.
> If pressure continues to climb at some point the AC will get cut out and
> the fan will still run at the higher speed until it drops.
>
> There are number of different pressure switch set ups. Most of the late
> vans use a single switch with multiple function often known as a trinary
> switch.
>
> Trinary switch functions
> Low pressure (lost charge) cut out.
> 2 speed condenser (radiator) fan.
> High pressure cut out.
>
> The 84 has none of these features or safeties. They just self-destruct
> when things go wrong.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf
> Of Jack Reynaert
> Sent: Saturday, August 22, 2015 2:25 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: Radiator Aux Cooling Fan 84 vs. 90
>
> When I run the AC on my 84 Westy, the Aux. fan on the Radiator runs as
> long as the power is on to the AC in back (regardless if the compressor is
> on).
> When I'm stuck in traffic, and the temp gage rises, the Aux fan does not
> kick-on by itself.  So, I turn on the AC, without compressor, and the fan
> kick's on and the temp gage goes down.  I suspect the temp sensor on the
> radiator is bad, and plan to change it.
>
> Now, my question is related to the Aux radiator fan on the 90 Westy we are
> just about complete with the mechanical overhaul (including new 2.2 GW
> motor, brake system, radiator, condenser, LED upgrades, dash rebuilt with
> AWESOME GW Kit, new everything that attaches to the GW motor as well).
>
> We took it for a ride today, and even at full operating temperature, the
> aux fan didn't kick on.  Put 12v to the fan motor and it worked fine, fuse
> #1 fine, power to the red/white wire to the switch etc.  However, when we
> turned on the AC, the aux fan didn't turn on (like it does on my 84)... is
> that normal for a 90?
>
> Any suggestions on likely causes (relay #53 or temp. sensor lower drivers
> side of radiator?)
>
> Thanks for any insight!
>
> Jack R.
> N. of Detroit
>