mzairboy Posted July 21, 2013 Share Posted July 21, 2013 I have a 1989 Comanche with Renix 4.0. It appears the electric fan has quit working, and the engine overheats. The mechanical fan works, but doesn't cool it enough. From the research I've done here, the electric fan should run when the AC is on, or when it reaches 230 degrees. Neither happens, so I believe it is a bad temp switch, or bad fan. I will test the fan, which I believe to be the issue. If the fan is bad, I can go to the junkyard and pull an MJ fan and plug n play. (I think its plug n play, I haven't even looked closely) However, the junkyards around here seem to be overloaded with Cherokees, and little to no MJs. The question is, can I simply plug a Cherokee fan into where the MJ fan plugs into, or do I need to rewire things? Any help will be appreciated, and I'll let you know my results. Link to comment Share on other sites More sharing options...
HOrnbrod Posted July 21, 2013 Share Posted July 21, 2013 If the fan is bad, any aux fan from an XJ will fit and work. I forget which year (95 or 96 I think) the connector changed and you may have to splice the connector from your old fan. Try to get to grab a 10-blade fan from a 1999 and up XJ as they pull more air. Link to comment Share on other sites More sharing options...
mzairboy Posted July 21, 2013 Author Share Posted July 21, 2013 Thanks for your help. I tested the fan and it works. If the fan is bad, any aux fan from an XJ will fit and work. I forget which year (95 or 96 I think) the connector changed and you may have to splice the connector from your old fan. Try to get to grab a 10-blade fan from a 1999 and up XJ as they pull more air. Link to comment Share on other sites More sharing options...
mzairboy Posted July 21, 2013 Author Share Posted July 21, 2013 So the fan works...hooked it up to the battery and it fired right up. That means a fuse is out, or the sensor is bad? It appears there is a temp sensor on the radiator, however I thought it was located on the engine block? Image Not Found Could someone help guide me as to where the fuse is located, and where the sensor that activates the fan is? Thanks! Link to comment Share on other sites More sharing options...
1989 Eliminator Posted July 22, 2013 Share Posted July 22, 2013 I had the same issue as you. This coolant temp. switch is located in the radiator as you have it shown. This detects the temp. of the coolent and is what triggers the aux fan to turn on when it get around 230 deg. The plug you are talking about in the engine block is located in the back right corner on the top, right next to the valve cover. This plug does not have anything to do with the aux fan. This only operates your temp. gauge on the inside. Things I did to solve this issue... I replaced that plug. (bought it from autozone) Replaced the relay that is for the aux fan. This I believe is what helped the issue. I refreshed my grounds which could have played a factor. Make sure you do not have any air at all in your system. If air is hitting that switch and not coolant, it will not work. This also will cause overheating. I also cleaned the contacts on all my electrical connectors. Good to do anyways I believe there is a fuse, but not 100%. If there is, it is under the dash by parking brake pedal. Link to comment Share on other sites More sharing options...
jons87mj Posted July 24, 2013 Share Posted July 24, 2013 The fan pulls its power from the selanod under the hood. It has a fusible link and travels down and across the grill and back up to the relay. My truck was wrecked on the driver side front. It didn't look bad but it was just anof to cut the wire. Link to comment Share on other sites More sharing options...
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