thanks Dennis,

so the cut A/C circuitry is not related to the rad fan behavior...

could you please tell me the exact location of the high speed rad. fan
relay and the number on it... thanks
I will replace the radiator fan switch and that relay... the resistor is
fairly new ( 2 years old)

dan

On Thu, Jul 25, 2019 at 11:40 AM Dennis Haynes <d23haynes57@hotmail.com>
wrote:

> If you can make 2 radiator fan speeds work by jumping the radiator fan
> switch than wiring is not your problem. For the low speed the fan the
> switch actually carries the current for the fan motor and the current-speed
> is limited by the resistor. This makes for a common failure of the switch.
> For high speed another relay, mounted above the fuse box is energized bring
> power direct from the battery to the fan motor to get the fastest speed
> possible. That high speed also disabled the AC compressor.
>
> So if that is working the next step is to test-replace the fan switch. The
> switches are available in a number of different temperature settings. The
> originals were set quite high to avoid nuisance running during hot weather.
> As the switch is sensing the coolant leaving the radiator it is normal for
> engine temperature to rise sometimes significantly before the fan is called
> for. Centered or just above the LED is where the engine temperature gauge
> should be normally. It is possible that due to a bad stat you may be
> running below temp so it will take longer for the coolant in the radiator
> to heat up to where the fan is needed.
>
> If the engine is truly running too hot and the fan switch is not sensing
> it you can have a coolant flow issue. A clogged or worse a radiator with
> internal section cracks can allow coolant to enter and exit without
> actually traveling through the core. If the engine case is damaged from a
> past water pump collision you may also have insufficient flow at idle  for
> the radiator fan switch to work.
>
> Dennis
>