As the title says, I got a p1491 CEL code.

The fan never turns on regardless of temperature, AC being on, etc.

The temperature gauge has gone over the normal midway mark and the AC is no longer cold, but isn't as hot if I'm driving fast.

What I have done to no avail:
replaced the relay on the inner fenderwell.
switched the 40 amp fuse with another 40 amp fuse.
replaced the wiring connection by fan with a direct wire to wire connection.

If I run a wire from the positive terminal on the battery to part of the exposed part of the harness where the connector used to be the fan turns on properly.

Please for the love of God save me.

Most likely a wiring issue.Bet the connector to the fan relay was melted a little right? If so time to start repairing wires.

If I am reading this correctly the fan works when powered directly at the connection so you can rule out a bad fan. If that's the case I would have checked the relay and the fuse, which you have done, and checked continuity to the connection before replacing the connection which you have not done. If that's all ok then you need to, cannot offer specific advice here, need to check the sensor in the AC system that "tells" the fan to turn on and at what speed as that fan does not run at all times. In addition, IIRC a low freon charge can also cause AC fan issues.

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Sold to LOST member my 05 Ltd, GDE Stg II turbo + TCM tune, SunCoast TC w. Transgo kit, Steiger window regulators, Samcos, Fumoto valve, 2nd gen filter head with Lub. Spec. bleeder, Hayden clutch & 11 blade fan, inverted spare, P-1 battery, BF Goodrich Long Trail TAs, Etecno1 glow plugs, timing belt at 50K miles/8 yrs

I haven't seen any indication of heat damage, but I could be missing something.



How do I check the continuity?
Where is the sensor in the AC system that talks to the fan?
How do I check my AC charge?

Latest update-

I decided a tactical pause is the best course of action on the fan business, so I just ran a circuit with fuse/switch between the fan and battery to the inside of the Jeep. In my head this will allow me to turn the fan on in instances of emergency until I can actually fix the problem.

I thought the AC would start being cold again with the fan running and I was wrong, the air is as cold as ever. What are the implications of this?

Continuity you can check with an inexpensive volt/ohm meter from like Radio Shack BUT you would likely need to look at the FSM wiring diagrams to see what circuits to check for a broken wire. In "my" world I tend to try the simple things first:
1. will fan work if powered directly - if so fan ok, if not replace fan
2. swap in known good fuse and relay - if fixes problem replace bad item; if not glance at FSM wiring to see if there is an easy way to check for continuity in the relay/fuse/fan circuit-if so check-if bad fix broken wire (unlikely but possible) if not at that point I've exhausted my AC ability
3. take to any decent AC shop to check freon level and AC switch that activates fan - if manually activating fan does not improve cooling I strongly suspect low freon which may be why your fan won't trigger.

I won't touch the "guts" of the AC system with a 10' pole as I lack both the training and the tools not to mention proper charging of the AC system is somewhat past the days of plug in a can of freon and let it rip.

Someone that knows more will have to weigh in.

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Sold to LOST member my 05 Ltd, GDE Stg II turbo + TCM tune, SunCoast TC w. Transgo kit, Steiger window regulators, Samcos, Fumoto valve, 2nd gen filter head with Lub. Spec. bleeder, Hayden clutch & 11 blade fan, inverted spare, P-1 battery, BF Goodrich Long Trail TAs, Etecno1 glow plugs, timing belt at 50K miles/8 yrs

What year KJ? and what engine? The newer years use a 2 speed fan.

It's a 2002 with the V6.

Okay where did you buy the fan relay at? If it was not the dealership and not the updated version with the large heatsink I'd start there and take a very good look at that relay connector.

Pic of updated fan relay...............

I bought the relay from Advance Autoparts and it does have the large heat sink as seen in your picture. I looked at the connectors and they appear to be in good condition.

I would assume the next step here is to test the relay and the wiring harness, but I have no idea how to do so. I bought a multimeter, but I'm not sure which setting it should be on or which connections to test.

How did you get a picture from that vantage point? I've been working on it from above and it's an extraordinary pain in the booty.

That right there could be the whole problem.

Use the OHM setting to check the continuity of the wires from one end to the other,the setting that looks like a horseshoe.

Outstanding...

Which wires am I testing?