Temp on highway 146 through town climbs as high as 214 no fan turn on any ideas??

Check the fuse and relay related to the AC. Your fan should come on when the AC is turned on. Right now the fan is working only off the engine temp., not the AC.

Radiator fan motor or radiator fan thermostat defective/

Also there is a relay that operates the fan motor

In town not enough air passing through radiator allowing it to over temp.. With heater fan running acts like cooling fan keeping engine cool

Highway driving ample air passing through radiator without fan.

Hill climbing requires cooling fan/

Hope this helps?

If you have a viscous fan hub attached to the fan then it will not be working at high speed as there will be enough air flowing through the radiator to keep things cool. They only really work at high engine loads and slow speeds (hill climbing ) and at stop lights where the air flow is nill

the fan will turn on when the engine temp reaches a set temperature and will only turn off when the engine drops below a certain temp and on the highway running hard it may stay on longer

Any performance testing re auto A/C requires consistant engine revs highway revs eg 1800 exit ramp eg idle stop start 800revs leading to much reduced A/C compressor speed and therefore performance output .Also all testing its desirable to close the bonnet to control design air flow through the engine bay .Also check under dash passenger side air flow pos a filter on return air duct or something sucked up into paper etc .good luck!

have auto zone run a scan on the truck its free overheating you need a seperate cooler for you trans pulling trailer put a high load on trans this will make the trans last longer and run cooler I would put the cooler as low as possible in the very front of your radiators

You are most likely right about the thermostat. the ST 1300 had that problem and it is always the thermostat. this also effects the fuel mileage. i would go ahead and replace it and see if that fixes your problems. Brian

the fan has a low and high speed or some have 2 fans. It comes on low speed when the temp starts to climb or when you turn the a/c, defrost, or mix mode (it turns on when the a/c compressor kicks on. If the temp of coolant gets to about 230 F, then the high speed kicks in.

What is your doing? Very nosiy sounds like high speed. Could be a defective ECT - engine coolant temp sensor.

When on the highway the wind blown through the grille naturally cools the rad coolant. While stuck in traffic the radiator fan will intermittantly cut in to prevent over heating, thus the fluctuations in the temp. gauge.

if the blower only blows on high then it is you blower motor resistor that is located behind the glove box it has two screws that hold it in place