shawn Posted November 15, 2015 Share Posted November 15, 2015 hi guys. just looking to see if anyone knows where i should start with this fan issue. it simply stopped coming on .if i pop the hood and tap the fan motor with a ski pole it comes on right away though. ( sometimes it makes some painful squeeling sound when i do this - sometimes it doesn't). bear in mind, electricity is still just some mysterious theory to me at this point. also, i have a parts xj that was just given to me. same year and running gear.( 91 4.0 5spd). Link to comment Share on other sites More sharing options...
Eagle Posted November 15, 2015 Share Posted November 15, 2015 The brushes inside are worn out, which is why it won't run -- and the bushings are dried out, which explains the squealing. Basically, you need a new blower motor. You can try one from a junkyard, and hope it'll last for a year or two, or you can spend a few $$$ more and get a new motor from Auto Zone or similar places. Link to comment Share on other sites More sharing options...
shawn Posted November 16, 2015 Author Share Posted November 16, 2015 i notice on the mj there's some sort of fuse or relay also bolted to the blower through one of the same 3 screws that holds it on. the xj doesn't have this. i'm going to assume i can just install it back onto the xj blower (that's going into the mj)? Link to comment Share on other sites More sharing options...
Eagle Posted November 16, 2015 Share Posted November 16, 2015 i notice on the mj there's some sort of fuse or relay also bolted to the blower through one of the same 3 screws that holds it on. the xj doesn't have this. i'm going to assume i can just install it back onto the xj blower (that's going into the mj)? i notice on the mj there's some sort of fuse or relay also bolted to the blower through one of the same 3 screws that holds it on. the xj doesn't have this. i'm going to assume i can just install it back onto the xj blower (that's going into the mj)? That does not sound like factory equipment. I've never seen an external fuse or relay for the blower motor. Can you post a photo of it? Link to comment Share on other sites More sharing options...
shawn Posted November 17, 2015 Author Share Posted November 17, 2015 it's this. sorry for the big pic. ive read that when the blowers struggling it can cause a dash fire because of resistance melting the switch. Link to comment Share on other sites More sharing options...
HOrnbrod Posted November 17, 2015 Share Posted November 17, 2015 The relay mounted on the blower fan screw is not factory. But it looks like it's been there for awhile. Can you trace the relay wires out to see what device this relay is tied to? And is this a pic of your 91? Link to comment Share on other sites More sharing options...
shawn Posted November 17, 2015 Author Share Posted November 17, 2015 yes its the 91. I'm going to change it out tomorrow. i didn't have time to trace the wires tonight but just from a glance it didn't seem to have anything to do with the fan. here's a recent pic of the truck now on 35s with the 4:10s from my 86. it's been horribly abused every day for many years now and i still wouldn't hesitate to drive it across the country tomorrow morning. i love this little truck. Link to comment Share on other sites More sharing options...
Eagle Posted November 17, 2015 Share Posted November 17, 2015 The heater blower controls use a pack of resistors to control fab speed. There are three different resistors, each for one of the intermediate speeds, and then a circuit route with no resistance for high speed. I wonder if your resistor pack burned out and a previous owner just wired in an external resistor rather than replace the resistor pack. When the fan runs, how many speeds do you have? Link to comment Share on other sites More sharing options...
shawn Posted December 1, 2015 Author Share Posted December 1, 2015 that's the thing. it ran on all speeds so i figured it was the motor itself. the relay in the pic turned out to be part of an after-market security system that the po had installed. i put the one from the parts jeep in and it starts and blows well, now a strange thing is going on where it will change settings by itself and alternate between blowing to the floor (heat setting), and blowing for de-fog. this is without the actual control lever moving at all. Link to comment Share on other sites More sharing options...
Fernando87mj Posted December 1, 2015 Share Posted December 1, 2015 If it goes to defrost randomly then you might have a intermittent vacuum problem since the defrost is the default setting and I could be wrong (correct me if I'm wrong ) but if you have a vacuum leak then it will default to defrost since the controls are vacuum actuated . Link to comment Share on other sites More sharing options...
shawn Posted December 1, 2015 Author Share Posted December 1, 2015 i did get a less-than-perfect seal on that hose piece that connects under the blower. hmmm not sure where else to check for a leak, but that does make sense. Link to comment Share on other sites More sharing options...
HOrnbrod Posted December 1, 2015 Share Posted December 1, 2015 Check the vacuum line that passes through the front bulkhead near the battery to the vacuum canister behind the bumper. It's a common rubbing place that creates vacuum leaks. Link to comment Share on other sites More sharing options...
cruiser54 Posted December 1, 2015 Share Posted December 1, 2015 Here: Link to comment Share on other sites More sharing options...
Virginia Posted July 7, 2017 Share Posted July 7, 2017 My heater blower would stop working when the air outside was hot so no air conditioning. I replaced the fan about 3 weeks ago and it was working fine then yesterday, I started the truck and nothing when I moved the switch to normal air conditioning. Was like that all day and until about 6:30 last night when it just randomly came on while I was driving. It had rained a bit so was a little cooler out. This morning, cranked the truck and it's still working fine but the moment it gets hot outside, I bet it will stop again. I'm thinking it's not the motor since it's new. What else could it be? Link to comment Share on other sites More sharing options...
cruiser54 Posted July 7, 2017 Share Posted July 7, 2017 On Renix Jeeps, it's always a good idea to add another ground per the following Tip: http://cruiser54.com/?p=211 Link to comment Share on other sites More sharing options...
Virginia Posted July 8, 2017 Share Posted July 8, 2017 On Renix Jeeps, it's always a good idea to add another ground per the following Tip: http://cruiser54.com/?p=211 Mine's a 91 and has 3 wires. Red, black and green. I assume the green is the ground. Can I just make a new ground connection with that wire? Link to comment Share on other sites More sharing options...
HOrnbrod Posted July 8, 2017 Share Posted July 8, 2017 On Renix Jeeps, it's always a good idea to add another ground per the following Tip: http://cruiser54.com/?p=211 Mine's a 91 and has 3 wires. Red, black and green. I assume the green is the ground. Can I just make a new ground connection with that wire? The 91 blower motor connector has only two wires, BLK and GRN. BLK is the ground wire, GRN comes from the blower motor resistor. Link to comment Share on other sites More sharing options...
cruiser54 Posted July 8, 2017 Share Posted July 8, 2017 On Renix Jeeps, it's always a good idea to add another ground per the following Tip: http://cruiser54.com/?p=211 Mine's a 91 and has 3 wires. Red, black and green. I assume the green is the ground. Can I just make a new ground connection with that wire? The 91 blower motor connector has only two wires, BLK and GRN. BLK is the ground wire. and, it doesn't really need the ground upgrade anyway. Link to comment Share on other sites More sharing options...
Virginia Posted July 8, 2017 Share Posted July 8, 2017 You're right. The green wire is part of the old connector. WHen I got the new fan, it had red and black wires so I connected the red and green together and the two black wires together because the new fan didn't come with the quick connector already on it. So, if the ground isn't the problem, what would make the fan just stop running then a day later suddenly start again? Link to comment Share on other sites More sharing options...
Jeep Driver Posted July 8, 2017 Share Posted July 8, 2017 Blower motor resistor, does the fan work in the high speed position? Link to comment Share on other sites More sharing options...
Virginia Posted July 9, 2017 Share Posted July 9, 2017 Blower motor resistor, does the fan work in the high speed position? When it stops running it doesn't work on any speed. Link to comment Share on other sites More sharing options...
MuddFoot Posted July 9, 2017 Share Posted July 9, 2017 Check the fuse see if it's melted on the fuse panel. I had one that had a bad connection at the fuse panel and would start and stop when the Jeep bounced around Sent from my Z981 using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted July 9, 2017 Share Posted July 9, 2017 Anything else quit working at the same time? Like turn signals, radio etc? Link to comment Share on other sites More sharing options...
Virginia Posted July 9, 2017 Share Posted July 9, 2017 Fuse is fine. Everything else is working. I went out this morning and the blower didn't come on. As I was pulling out of my driveway I moved the switch from "normal" to "off" and as I passed the "Max" mark the blower came on. I moved the switch down to normal and cycled through the fan speeds and everything worked fine. I also noticed while I was rolling that before the fan came on, I could feel cold air just barely coming out of the vents but it would stop when I stopped rolling. I opened the rectangle fuse box under the hood and pulled the big square fuse that was marked air conditioner and 2 of the prongs looked slightly discolored. I'm not sure where the resistor is. Link to comment Share on other sites More sharing options...
HOrnbrod Posted July 9, 2017 Share Posted July 9, 2017 I opened the rectangle fuse box under the hood and pulled the big square fuse that was marked air conditioner and 2 of the prongs looked slightly discolored. I'm not sure where the resistor is. It's call the PDC (Power Distribution Center) and what you pulled was the A/C relay. The blower resistor is in the passenger side duct under the dash behind a small plastic cover. Link to comment Share on other sites More sharing options...
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