Hayden Fan Electrical Circuit on 2000 LXi

[davidbrady]

Hi Chuck,

Thanks for the write-up - that's great info.

Short of wiring in another fluid temperature probe or an LED 'Fan On' indicator in the Hayden fan circuitry (which may eventually be a good idea), we can learn a lot by simply observing the hydraulic fluid.

Here's a fascinating link I ran across that talks about hydraulic fluid testing, typical test results, and fluid color and smell.

The idea of monitoring fluid color, smell, and levels is also probably the best way of determining general seal failure. We have many places in our drive-trains where one fluid is separated from another by a single seal: hydraulic steering pumps on our Series-60 separating hydraulic fluid from engine oil; coolant pump on our Series-60 separating coolant from our engine oil; Series-60 oil cooler bathed in engine coolant; transmission cooler bathed and enclosed in radiator top tank; and PTO and fan pump wet spline kit separating transmission fluid from hydraulic fluid.

In many of these cases an early indicator of issues would be tainted fluid; that is, unusual fluid levels, smells, and colors.

Periodic fluid testing is also a very good idea - if only I could be so disciplined.