Hill2004

I have a 2004 Jeep Grand Cherokee special edition. I have replaced both low and high speed relays along with the coolant sensor. I have checked the fan and it works . Cooling fan still will not come on when AC is turned on . Any help would be appreciated

Firehawk068

Does your A/C work?
Have you verified that the A/C compressor kicks on?
Fan won't turn on unless the A/C system is functioning properly.

Hill2004

Yes compressor appears to be functioning properly. At my wits end trying to figure this one out.

freegdr

Newer xj fan dont come on untill high head pressures reached. Maybe yours set up same way ?

Hill2004

Thanks I did not know about that head pressures activating fan. Is there a test for this? New to the group and still learning the navigation

Morris4x4Center

Are you saying the fan never comes on by itself? ever?

and / or is the vehicle is overheating? That's the initial problem?

dave1123

Okay, here's a little info on how my '00 WJ 4.0 works. There is a "pulse modulated" relay underneath the right headlight that controls the fan by way of the PCM (computer). When the temp reaches 210*, the fan comes on low. This is thermostat set temp. When it reaches 215*, it comes on high. It drops back to low after it returns to 190*. This is the way it's SUPPOSED to work.

Many people have had problems with the cooling fans, especially the hydraulic ones. There are several write-ups on this forum about people that converted to electric fans and how they accomplished temp control. One guy even listed his parts and wiring drawings. Do a search for "electric fan installation".

Hill2004

Just got the jeep about two weeks ago so still feeling it out. Original fan had one side that would not come on when bench tested with battery so a new one was tested and installed. Vehicle is not overheating because of the clutch fan on engine.

Hill2004

Yes , I read the post about the relay being located under the headlight . I guess in 04 they made some that way and others were changed to two relays a high and a low speed relay. Trust me I cut the hole under the light only to find nothing.

Hill2004

I have never heard it come on except on the bench test....