I have been having some odd temp spikes lately and also noticed I don't remember my fan kicking on. I turned on the AC and set it on high and the fan stayed off, I thought it was supposed to spin up when the AC was on? Is there a way to check the actuation of the fan at the relay box or some other little trick?

Thanks,
Clay

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2005 Sport CRD
GDE Eco Tune
245/75 on Moabs
Magnaflow (ish) exhaust

There is also some air temp dependence to the activation, but I don't know what the parameters are.
You can just check the motor by pulling the low speed relay while the engine is idling. You should hear the fan come on. Put it back in and pull the high speed relay, again you should hear it come on. IIRC it goes through both speeds when you mess with either of the relays. I wish I could describe it more clearly but it's been a while.

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05CRD: GDE Hot ECU & TCM tunes, Provent, Cat filter, Facet lift pump, TransGo kit, Florida TC, Samcos, stainless brake lines, HDS thermostat, Renegade light bar,
Bilstein adjustables, Al's Gen 4.5 Arms, 235/85-16 Duratracs, DTT rear, Elocker front, EVIC+TPMS, Turbo timer, McNally pillar gauges, Weeks Stage II kit.

Just to get it out there the electric fan just behind the grill is not the engine cooling fan although I suppose it indirectly provides some additional air flow across the radiator in some situations. It is the AC condenser cooling fan and IIRC kicks in only as needed, not sure what sensor it uses, for proper AC performance when the AC is on. Catcrd is correct it does have 2 speeds via relays R34 and R40. Could be the fan is dead (somewhere on here there is a chat about one that died and IIRC it was diagnosed by running battery power direct to the fan wiring); could be bad relay(s); or could be blown fuse F2. The relays and the fuse are all in the power distribution center.

Since you have an 05 the more likely cause of temp rise is a bad mechanical fan clutch, not uncommon on the 05. Fix is a Hayden 2905 heavy duty clutch. A DIY install but getting the fan and fan shroud off can be an issue (see http://www.beesvillebeefarm.com/jeep.html for one method) and while in there do a fan shroud mod for future ease of access (see viewtopic.php?f=98&t=64278&p=709322#p709322)

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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

Good to know that the fan is a AC only device. I pulled the relays and the fan kicked on so that part is OK.

I should have mentioned that 10k miles ago I switched over to a Hayden clutch along with a new water pump, thermostat, radiator and hoses during the belt change. I had weird temp issues before then and was hoping to clean them up.

I am not sure it is an actual overheat but may be a sensor issue because I go from middle of the dial to chime ringing in about 45 seconds and then back down in a bout the same time after I back off the throttle.

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2005 Sport CRD
GDE Eco Tune
245/75 on Moabs
Magnaflow (ish) exhaust