Tdorn

OK I popped my hood when I got home today to check the oil and I saw that my electric fan was not running but a few min went by and it started to work after a closed the hood it stop. Are those fan suppose to run full time? its been running about 200 the last week.And I have know idea what a jeep it suppose to run at.

Pelican

Forever and always: Year

Tdorn

Sorry lol its a 99 cherokee sport with a 4.0L

1976Mustang

they do not run all the time, only when the engine is hot enough. And some times it comes on with the A/C, depends what year.

94XjSport94

Yep.

Turn it on and open the hood and listen/ observe.
Your fan will come on at 218*, if the AC is on, or by a aux switch.

Unplug the thermostat sensor and it should kick on, and throw a CEL.

nathan94xj

What's it mean if it comes on when you unplug it? Is sensor bad?

94XjSport94

Means that circuit works and the fan works lol. The circuit reads open and freaks the computer out so the fan comes on

nathan94xj

Would that cause a incorrect readin on temp guage I did the cluster swap so I could see temp instead of dummy lights. I replaced temp sendin unit twice and temp guage climbs to 240 within 5 minutes of idle everythin in cooling system new. Bugging crap outta me. Do you think bad cluster?

94XjSport94

The gauge reading comes from the sending unit on the back of the head, not the thermostat housing. Verify that temp with an IR thermometer

nathan94xj

Ya that's the one I replaced twice. I will try that but I think it's a bad guage cause motor don't feel like its getting as hott as the guage says it is

94XjSport94

Get the temp on the thermo housing and go from there. Might be a bad gauge after all

nathan94xj

Ya I've replaced water pump upper lower hoses thermostat back sending unit fan clutch

nathan94xj

Temp still creeps up on guage

Tdorn

ok thanks for the help guys

Pelican

OP, I've lost track here -- have you solved your problem?