NewJerseyXJ609

Hey guys hopefully someone can give me a couple pointers. Working on a 99 xj not mine personally but for a friend and he has a cel on for the aux fan. The fan turns on when the ac is on and seems to be working when the jeep gets to temperature. It's hard to say because he has the idiot light guages. I'm swapping his cluster over when I do his heater core.. Anyways. Will I get a cel for the fan if it kicks in late? In other words if by the ecm its supposed to be kicking in at 213 but it turns on at 216 will that throw the code? What are the values its supposed to start and stop on? I could always hit it with an infrared gun.

Background on the jeep: 99 4 door auto. l6 120k. Lifted 3 inches on 31's motor is seemingly stock besides a cai.

djb383

'98 FSM says approx 218F on and approx 209F off. If the elec plug on the t-stat cover is disconnected, the efan defaults to "on" and a CEL is set.

NewJerseyXJ609

Good to know thank you ill check into that plug.

prcherokee

Electric cooling fan 4.0L: With or without A/C
request the electric fan will come on only when the
coolant temperature is at least 106° C (223° F), and
will remain on until the coolant temperature drops to
103° C (217° F) or below. Regardless of coolant temperature,
When air conditioning system pressures
reach 2068.5 6 138 kPa (300 6 20 psi) the electric
fan will engage and continue to run until the A/C
system pressure drops to 1620.3 kPa (235 psi) minimum,
then the electric fan will shut off.

NewJerseyXJ609

Thank you for the info.. So far I have some contradicting values but ill still see when the fan is coming on using an infrared gun and go from there

prcherokee

This are not my numbers they are from the Jeep repair manual.I copy and pasted.