Eagle Posted August 10, 2013 Share Posted August 10, 2013 I just had to replace the blower resistor pack in my 2000 XJ ... AGAIN! Mice keep building nests in the blower box, the nest material insulates the resistor pack, and it blows. The resistors themselves are (or seem to be) fine. There's also a very small "thingie" in there that looks more like a capacitor (but probably isn't -- this isn't my area of expertise). It must act as a thermal fuse. The new unit has continuity across this "thingie" -- the blown one does not. The resistor pack costs $74.00. I've got to think that it should be possible to make a bench repair and replace this fuse thing for a lot less than that. Does anyone on this forum have the electronics expertise to figure out what this is and what to use to replace it? If there's a volunteer, I can send you the blown resistor unit for you to examine first-hand. I'm tempted to jumper it and see if that would work, but it has to be there for a reason, so perhaps that's not a good idea. Thoughts? Link to comment Share on other sites More sharing options...
onlyinajeep726 Posted August 10, 2013 Share Posted August 10, 2013 I have a better idea... Figure out how those little bastards keep getting into your XJ to begin with and prevent further nests from being built lol. And keep a couple set mouse traps in the blower box so if they do get back in, you'll know it. Link to comment Share on other sites More sharing options...
jimoshel Posted August 11, 2013 Share Posted August 11, 2013 That "Thingie: is a thermal fuse. It blows if it senses too much heat. The heater will work just fine without it. However there is a reason for it blowing. Might try putting a amp meter in the circuit and seeing just how much currant it is drawing. From the symptoms you describe, I would suspect the blower motor. If you can reach it, feel it after running a couple minutes. Feel if it's hot or not. If you do decide to jump it, there's the 25 amp fuse in the fuse box so you've still got some protection. If it is the blower motor, try a drop of oil on the bearings. Also make sure the area around the entire resister assembly is clean and clear of any dirt, trash or debris. Link to comment Share on other sites More sharing options...
HOrnbrod Posted August 11, 2013 Share Posted August 11, 2013 This is the blower motor resistor pack from a Benz Sprinter van (4-speed blower motor):The thermal fuse was blown, the blower only ran on HI. The thermal fuse was replaced by the below from Radio Shack. It's DC amp rating (converted from the AC specs) is close the the Sprinter original thermal fuse rating (actually a bit less, better protection, according to the article) which is very close to the Jeep MJ/XJ blower motor specs:http://m.radioshack.com/radioshack/product/detail.do?itemId=2102788&categoryId=&path=catalog%20#Three years later, the blower motor is still running on all speeds. Worth a shot for $1.99 + tax. Link to comment Share on other sites More sharing options...
jimoshel Posted August 11, 2013 Share Posted August 11, 2013 I meant to say that but in my rambling I didn't. You ask for a thermal fuse by heat rating. Not amps. The value here is 148* Centigrade Link to comment Share on other sites More sharing options...
Eagle Posted August 11, 2013 Author Share Posted August 11, 2013 That "Thingie: is a thermal fuse. It blows if it senses too much heat. The heater will work just fine without it. However there is a reason for it blowing. Might try putting a amp meter in the circuit and seeing just how much currant it is drawing. From the symptoms you describe, I would suspect the blower motor. If you can reach it, feel it after running a couple minutes. Feel if it's hot or not. If you do decide to jump it, there's the 25 amp fuse in the fuse box so you've still got some protection. If it is the blower motor, try a drop of oil on the bearings. Also make sure the area around the entire resister assembly is clean and clear of any dirt, trash or debris. I know why it blew -- I covered that. Mice built a nest in the blower, as well as stuffing nest material around the thermal fuse. Yes, the heater will work -- on high speed only. I want to be able to use al speeds. I have cleaned out the blower and replaced the resistor pack, but I'd like to repair the old one to keep around as a spare. I have three new-style XJs (two 2000s and one 2001), so the odds are that I may need another one some day. Link to comment Share on other sites More sharing options...
Eagle Posted August 11, 2013 Author Share Posted August 11, 2013 I meant to say that but in my rambling I didn't. You ask for a thermal fuse by heat rating. Not amps. The value here is 148* Centigrade How did you determine the temperature rating? For two bucks, I'll give it a try but there's a big difference between 148 degrees C and 228 degrees C. The higher temp rating would require a different solder than what's normally used in electronics. Link to comment Share on other sites More sharing options...
jimoshel Posted August 11, 2013 Share Posted August 11, 2013 Got it from the 1989 MJ service manual. Sorry. Don't have a 2000 SM. but there shouldn't be that much difference. Radio Shack or any appliance repair facility should carry them. You may not get the exact 148 value, unless you go to the stealership but ti's not that critical Anything a couple degrees either way will work. Like was said previously. They work by sensing heat. Resistors produce heat. Make sure the area around the resistors is clean and there is free air flow around them. Link to comment Share on other sites More sharing options...
Eagle Posted August 11, 2013 Author Share Posted August 11, 2013 You won't find the thermal fuse at a Jeep dealer. The resistor pack is not serviceable -- replace only. Looks like Radio Shack has one rated at 140 degrees C (288 degrees F). That's maybe close enough, and will allow me to use regular electronic solder. Looks like I'll be visiting my local radio Shack tomorrow. Thanks, Gents. This is what I hate about modern society. Rather than replace a $2.00 fuse, they want you to replace the entire resistor pack -- for $75.00. Unfortunately, at today's labor rates it's probably cheaper for a shop customer to do it that way rather than pay a technician to repair the original resistor pack and then replace it, but it's tough on us do-it-yourselfers who aren't paying for labor, only for the parts. Link to comment Share on other sites More sharing options...
danbyrambler Posted August 11, 2013 Share Posted August 11, 2013 Mice - Have dealt with them constantly over the years - part of farm living - Sure you know a vehicle or anything will be a target/preferred place once the scent thing is established - - Anyway, if you can't keep 'em out of the BB you might want to relocate the resistor pack - - Dunno - If it's just a 4 pin plug in should be easy enuff to get it outta the housing - I know this is a treating the symptoms instead of the disease approach - Curious that they haven't been chewing wires - Dunno, just sayin' - Care for some Gopher? Link to comment Share on other sites More sharing options...
tugalo Posted August 11, 2013 Share Posted August 11, 2013 Might try a little peppermint oil inside the heater box, mice are allergic to it and will stay away. Smells good too. Link to comment Share on other sites More sharing options...
Eagle Posted August 11, 2013 Author Share Posted August 11, 2013 I find it interesting that the '88 FSM gives the actual temperature rating for the thermal fuse, and the 2000 FSM doesn't even mention it. In fact, looking at THREE wiring diagrams where the resistor pack is shown, the thermal fuse itself isn't shown and there's no indication of how it works. The factory clearly doesn't want anybody fooling around, trying to repair one of these resistor packs instead of just buying a new one. Link to comment Share on other sites More sharing options...
jimoshel Posted August 11, 2013 Share Posted August 11, 2013 Personally, I think I would just solder a piece of wire across it and forget about it. Link to comment Share on other sites More sharing options...
danbyrambler Posted August 11, 2013 Share Posted August 11, 2013 Anybody smell smoke? :hmm: Link to comment Share on other sites More sharing options...
Eagle Posted August 11, 2013 Author Share Posted August 11, 2013 Radio Shack ain't what it used to be. Stopped by a local Radio Shack store that happens to be very near the Lowe's I had to go to anyway. Kid in a red shirt led me to a bunch of drawers labeled "Fuses," and proceeded to pull out one envelope after another of glass, cartridge fuses -- after I had given him the part numbers I was after and pointed at one that was the same type and said, 'They'll look like this, but with different temperature ratings." Finally found the higher rated one (the part number from Hornblod's post), but couldn't find the one rated close to the Jeep spec. I did find one that's rated even lower, so I took the ONE fuse they had in that rating and I think I'll try that one first. Then I went looking for rosin-core solder. They had 60/40, they the old triple-component solder in whatever proportion that comes in, and they had "lead free" solder. I asked the kid what the melting temperature is on the different types. He didn't know. In fact, he couldn't even pronounce "solder." I asked him what's in the lead-free solder, since traditionally solder is a lead+something alloy. He didn't know. Sheesh. But I'll bet he can tell me everything about an iPhone 5 ... Link to comment Share on other sites More sharing options...
jimoshel Posted August 11, 2013 Share Posted August 11, 2013 You would probably have better luck at an appliance repair facility. They're used in almost every appliance that produces heat. Dryers, micro waves, ovens, coffee makers, etc. etc. If you really have trouble finding solder, let me know. I have several dozen rolls of 60/40 rosin core for electronic equipment repair Link to comment Share on other sites More sharing options...
nitroxsteve Posted August 12, 2013 Share Posted August 12, 2013 Auto zone has the resistor for 33.99 part number 20118. I have used this one with no problems. They also show one for 21.99 part number MT1814 I'm not sure what the difference is. Much better than $74.00 Link to comment Share on other sites More sharing options...
Eagle Posted August 12, 2013 Author Share Posted August 12, 2013 Auto zone has the resistor for 33.99 part number 20118. I have used this one with no problems. They also show one for 21.99 part number MT1814 I'm not sure what the difference is. Much better than $74.00 But the actual resistors in my resistor pack are fine. I'd much rather spend two bucks and a few minutes with a soldering gun to repair the old one, if possible. Link to comment Share on other sites More sharing options...
Eagle Posted August 12, 2013 Author Share Posted August 12, 2013 You would probably have better luck at an appliance repair facility. They're used in almost every appliance that produces heat. Dryers, micro waves, ovens, coffee makers, etc. etc. If you really have trouble finding solder, let me know. I have several dozen rolls of 60/40 rosin core for electronic equipment repair They had 60/40, no problem there. They didn't have 50/50. My real concern was that the kid couldn't tell me the melting temperatures. The lower temp fuse I found is only rated for 128* C and I would prefer not to blow it while soldering it in place. Guess I'll just have to make liberal use of heat sinks. Link to comment Share on other sites More sharing options...
jimoshel Posted August 12, 2013 Share Posted August 12, 2013 JB Weld? Link to comment Share on other sites More sharing options...
HOrnbrod Posted August 12, 2013 Share Posted August 12, 2013 JB Weld? :agree: JB Weld will work just fine. Shiny clean contact points, tightly crimp wires around pins, finish with a couple of JB dabs. Link to comment Share on other sites More sharing options...
Eagle Posted August 12, 2013 Author Share Posted August 12, 2013 Really? JB Weld is conductive? I never knew that. Link to comment Share on other sites More sharing options...
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