Initial Inspection and Diagnostic Overview

There are two cooling fans-a pusher and a puller. The fans run together at three different voltage levels to create three speeds or stages.
^ Low speed - both fans in series-6 volts each.
^ Medium speed-both fans in parallel with resistor in series - 9 volts each.
^ High speed - both fans in parallel without resistor - 12 volts each.
The fan speed selected is based on coolant temperature or A/C system high side pressure.
L81
Low speed
^ Enabled if coolant temperature exceeds 96° C (204° F) or A/C system pressure exceeds 1199 kPa (174 psi).
^ Disabled if coolant temperature goes below 92° C (198° F) and A/C system pressure goes below 799 kPa (116 psi).
Medium speed
^ Enabled if coolant temperature exceeds 99° C (210° F) or A/C system pressure exceeds 1695 kPa (246 psi.)
^ Back to Low speed if coolant temperature goes below 97° C (207° F) and AIC system pressure goes below 1399 kPa (203 psi).
High speed
^ Enabled if coolant temperature exceeds 102° C (215° F) or A/C system pressure exceeds 2398 kPa (348 psi).
^ Back to Medium speed if coolant temperature goes below 100° C (212° F) and A/C system pressure goes below 2198 kPa (319 psi).