1990 Mercury Topaz Radiator Fan

The easiest way to check the fan is to run wires from the battery terminals to the fan connector, if it runs check the switch near the thermostat, they cost about $20.00 at autozone
Here's how and what to test:
COOLING FAN (TEMPO & TOPAZ WITH A/C) 1. Ensure all fuses are okay. Check Black fusible link to cooling fan relay and Blue fusible link to cooling fan controller. Replace as necessary. If okay, determine when cooling fan does or does not operate. If it operates during A/C operation only, proceed to step 2). If cooling fan does not operate during A/C operation or during high engine coolant temperatures, proceed to step 11). If it operates during high coolant temperatures only, proceed to step 5). 2. Ensure "A/C" and "DEFROST" are off. Disconnect cooling fan temperature switch connector. Switch is located on upper left-hand side of engine, near the ignition coil. Install jumper wire between Tan/Orange wire and ground. See Fig. 5 . Turn ignition on. If cooling fan operates, proceed to next step. If cooling fan did not operate, proceed to step 4). 3. Ensure continuity exists in Brown/White wire to ground. If not, repair open circuit. With engine coolant temperature greater than 210 °F (85 °C), continuity should exist between terminals and cooling fan should operate. Replace cooling fan temperature switch if cooling fan operates. 4. Remove connector from cooling fan controller. Cooling fan controller is mounted on right cowl panel, under instrument panel and can be serviced through glove compartment opening. Check for continuity of Tan/Orange wire from controller to the cooling fan temperature switch. If continuity exists, replace cooling fan controller. If no continuity exists, repair open circuit. 5. Check that continuity exists from Black wire from cooling fan controller to ground. Repair circuit if no continuity exists. If ground circuit is okay, proceed to next step. 6. Remove connector from cooling fan controller. Check that voltage exists at Tan/Yellow and Light Green/Purple wires. If voltage exists, replace cooling fan controller. If no voltage exists, proceed to next step. 7. Remove connector from clutch cycling pressure switch and install a jumper wire between connector terminals. Switch is located on top of accumulator for A/C system. If cooling fan operates, proceed to next step. If not, proceed to step 9). 8. Check A/C system for refrigerant charge pressure of 50 psi (3.5 kg/cm 2 ) with ambient temperature of approximately 50 °F (10 °C). If no refrigerant pressure exists, leak test, service and recharge system. If refrigerant pressure is above 50 psi (3.5 kg/cm 2 ), replace clutch cycling pressure switch. 9. Remove connector from A/C push button on dash assembly. Check for voltage at Light Green/Purple and White/Light Blue wires. If voltage exists, replace A/C button switch and proceed to next step. If no voltage exists, repair open wiring circuits. 10. Remove connector from clutch cycling pressure switch and install a jumper wire between connector terminals. Switch is located on top of accumulator for A/C system. If cooling fan operates, proceed to next step. If not, check for open or shorted circuit in Light Green/Purple and Tan/Yellow wires between cooling fan controller and clutch cycling pressure switch. 11. Remove connector from cooling fan. Apply battery voltage to Brown/Yellow wire and ground the Black wire. If cooling fan operates, proceed to next step. Replace cooling fan if it fails to operate. 12. Install connector on cooling fan. Remove connector from cooling fan controller. With ignition on, check for voltage at Gray/Yellow, Tan/Yellow and Light Green/Purple wires. Check that continuity exists between Black wire and ground. Repair if necessary. If all circuits are okay, proceed to next step. 13. Apply battery voltage at Brown/Yellow wire of cooling fan controller. If cooling fan operates, replace cooling fan controller. 14. If cooling fan failed to operate, remove connector from cooling fan relay. Apply battery voltage at Brown/Yellow wire of cooling fan relay which goes to the cooling fan. This by- passes contacts of the relay. If cooling fan operates, proceed to next step. If cooling fan does not operate, check cooling fan ground circuit and cooling fan operation. 15. Ensure battery voltage exists at Yellow wire of cooling fan relay. Ensure continuity exists between Black wire at cooling fan relay and ground. Install connector on cooling fan relay. Apply battery voltage at Brown/Yellow wire of cooling fan relay. If fan does not operate, replace cooling fan relay. COOLING FAN (TEMPO & TOPAZ W/OUT A/C) 1. Disconnect cooling fan connector. Install jumper wire between Black wire and body ground. Apply battery voltage to Brown/Yellow wire. If cooling fan does not operate, replace cooling fan. If cooling fan operates, reconnect cooling fan connector and proceed to next step. 2. Disconnect electrical connector at cooling fan temperature switch. Cooling fan temperature switch is located in thermostat housing. With ignition on, check for battery voltage at Tan/Orange wire of connector. See Fig. 6 . If voltage exists, proceed to next step. If no voltage exists, check for an open or short in Tan/Orange wire circuit or fusible link. Repair as necessary and recheck operation. 3. Install jumper wire between terminals of cooling fan temperature switch connector. With ignition on, cooling fan should operate. If fan operates, replace cooling fan temperature switch and recheck operation. If not, leave jumper wire connected and proceed to next step. 4. Disconnect electrical connector at cooling fan relay. Relay is located on left radiator support, near the headlight. Check for voltage at Brown/White wire and Yellow wire of connector. If voltage does not exist, repair open or short in wiring circuits. 5. If voltage exists, install connector at cooling fan relay. Ensure continuity exists at ground circuit (Black wire) for cooling fan relay. Repair circuit if necessary. Install jumper wire between Yellow wire and Brown/Yellow wire terminals. If cooling fan operates, replace the relay. 6. If cooling fan did not operate in step 5), disconnect cooling fan connector. With ignition on and jumper wire installed on cooling fan temperature switch, check for battery voltage at Brown/Yellow wire to cooling fan. If battery voltage exists, proceed to next step. If voltage did not exist, check Brown/Yellow wiring circuit for an open or short. Repair as necessary and recheck operation. 7. Check for continuity at Black wire and ground at cooling fan. If continuity exists, replace cooling fan motor, connect cooling fan temperature switch connector and recheck operation. If no continuity exists, repair open ground circuit. Connect cooling fan motor connector and temperature switch connector and recheck operation.
3/11/2010 ...

Thanks!

Russellcruie Thank you for the kind words, It's nice to be appriciated!