ComancheFan Posted October 8, 2019 Share Posted October 8, 2019 Ok so now that I have gotten my Freon leaks fixed I found a new problem. When I turn the air or heat after about 5 minutes the fuse in the fuse box will melt. I’m hoping someone can point me in the right direction as to where the problem is? A short somewhere in the wiring? A corroded connection? Link to comment Share on other sites More sharing options...
Pete M Posted October 8, 2019 Share Posted October 8, 2019 have you added a ground to the fan wiring? Link to comment Share on other sites More sharing options...
ComancheFan Posted October 8, 2019 Author Share Posted October 8, 2019 Thanks for the quick reply, are you referring to the ground wire coming right off the blower? It appears the blower has been changed before as there is shrink wrap on the ground and positive wires. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 8, 2019 Share Posted October 8, 2019 1 hour ago, ComancheFan said: Thanks for the quick reply, are you referring to the ground wire coming right off the blower? It appears the blower has been changed before as there is shrink wrap on the ground and positive wires. Pete is referring to this: CRUISER'S MOSTLY RENIX TIPS IMPROVING BLOWER MOTOR PERFORMANCE NOVEMBER 28, 2015 CRUISER54 24 COMMENTS On 87 to 90 MJs and XJs, the blower motor’s factory grounding point is on the driver side inner fender under the sheet metal screw. This ground is shared with windshield wipers, front windshield washers, rear windshield washers, AC clutch relay, fan control relay, fog lamps, fan motor, headlamps, front turn signals, front side markers, and park lamps. So your blower motor has its ground point 10 feet away from where it is located!! What we’re going to do is leave that ground intact and also ground the blower motor on the passenger side inner fender much closer to the blower motor itself. This will also benefit the other components on the factory ground circuit. Take this opportunity to refresh the factory ground as a matter of course. Remove the screw, scrape the surface to bare metal and reinstall the screw securely. Here’s what I do to get the ground much closer to the blower motor and add another ground point to this overloaded ground circuit. Find the blower motor connector on the passenger side. Red and Black two wire connector. Find a location where the black wire can be made to reach the passenger side inner fender, and cut the wire. You may have to do some rerouting of the harness to achieve this. Take both cut pieces of wire and put them together into a yellow eyelet and crimp. Fasten the eyelet to a place on the passenger side inner fender with a sheet metal screw after applying OxGard to the contact surfaces. Be sure to scrape the attaching point on the fender to bare metal first. Your blower motor will now turn faster and last longer, and the other electrical components on the circuit will benefit from a better ground path. Link to comment Share on other sites More sharing options...
Ωhm Posted October 8, 2019 Share Posted October 8, 2019 Does Blower Fuse (25A) melt regardless of fan speed setting (LO M1 M2 HI)? Blower Fuse also feeds (B+) to the AC Compressor Clutch. Link to comment Share on other sites More sharing options...
ComancheFan Posted October 9, 2019 Author Share Posted October 9, 2019 The fuse was melting regardless of the fan speed. I just cleaned up the ground and added a ground close to the blower. This was definitely a problem as when my lights were on my directional light in the cluster would stay lit up. I've been driving around like that for around 100k miles. Cleaning the ground fixed that. I also cleaned the contacts in the fuse box. I took my jeep for about a 30 minute ride and the fuse got hot and slightly melted but not near as bad as before. Link to comment Share on other sites More sharing options...
ComancheFan Posted October 9, 2019 Author Share Posted October 9, 2019 So I guess where should I go from here? I remember that I once has a 1988 cherokee that the blower didn't kick in at all and it ended up being a badly burnt connector behind the climate control panel. Maybe I should look there? Link to comment Share on other sites More sharing options...
Pete M Posted October 9, 2019 Share Posted October 9, 2019 what's the condition of the resistor panel? Link to comment Share on other sites More sharing options...
ComancheFan Posted October 9, 2019 Author Share Posted October 9, 2019 It has seen better days. There's a lot of wires that are spliced into and wires that are cut in the harnesses around the panel. The issue is I'm not sure what the wiring should look like. Link to comment Share on other sites More sharing options...
Pete M Posted October 9, 2019 Share Posted October 9, 2019 those are the relays, I speak of the resistor panel or resistor pack. it has a harness plugged into it and is inside the duct right above the passenger's feet. iirc, it's held in with a pair of 8mm screws? Link to comment Share on other sites More sharing options...
ComancheFan Posted October 11, 2019 Author Share Posted October 11, 2019 Well here's what it looks like I'm going to get abd clean up the connections. It appears the connector has been replaced once. Link to comment Share on other sites More sharing options...
ComancheFan Posted October 11, 2019 Author Share Posted October 11, 2019 Link to comment Share on other sites More sharing options...
ComancheFan Posted October 11, 2019 Author Share Posted October 11, 2019 Ok I cleaned the connections and the resistor. The fuse is still melting. I felt the wires that go to the blower and the resister. Neither are getting warm if that helps narrow down my problem. Link to comment Share on other sites More sharing options...
Ωhm Posted October 11, 2019 Share Posted October 11, 2019 Disconnect C236 at the AC Mode Select Switch (climate control panel) and leave it disconnected. Determine if Blower Fuse still blows. You may have to drive vehicle around for a while, since fuse fails to blow instantly. Link to comment Share on other sites More sharing options...
Warren Mohler Posted October 12, 2019 Share Posted October 12, 2019 most times when a fuse melts not blown but plastic is melted the problem is at that connection in the fuse block what I am saying is the fuse is loose in its connection causing high resistance I have two in my block that did same thing, dome and turn signal fuses, had to do some creative wiring to work around problem I would like to replace all fuse block terminals but don't think my back is up for all of that at the moment Link to comment Share on other sites More sharing options...
ComancheFan Posted October 12, 2019 Author Share Posted October 12, 2019 I'm not sure where the plug your referring to is. Maybe its allready been cut out and replaced? Link to comment Share on other sites More sharing options...
ComancheFan Posted October 12, 2019 Author Share Posted October 12, 2019 Link to comment Share on other sites More sharing options...
ComancheFan Posted October 12, 2019 Author Share Posted October 12, 2019 With the brown fan speed plug unplugged it does nothing. With the black 2 wire switch unplugged it still melts the fuse. Link to comment Share on other sites More sharing options...
ComancheFan Posted October 12, 2019 Author Share Posted October 12, 2019 Link to comment Share on other sites More sharing options...
ComancheFan Posted October 12, 2019 Author Share Posted October 12, 2019 Now that I think about it should that black plug have more than just the two wires connecting to the 5 plug? Link to comment Share on other sites More sharing options...
Ωhm Posted October 13, 2019 Share Posted October 13, 2019 19 hours ago, ComancheFan said: Now that I think about it should that black plug have more than just the two wires connecting to the 5 plug? Yes WOW! What a mess, both under dash and under hood, I hope you live next door to a fire station. Which of the cavities are in use on C236? Your wiring might go 'beyond me and my keyboard'. 19 hours ago, ComancheFan said: With the brown fan speed plug unplugged it does nothing. Also with C235 disconnected, that's trying to tell you something. Follow them wires. Link to comment Share on other sites More sharing options...
ComancheFan Posted October 13, 2019 Author Share Posted October 13, 2019 Ok. So I'm missing a wire for the D and A plug on the C236. The bare wires were to the radio. I just put butt connectors in the place. And I did the same where the harnesses have been cut into. In the c236 plug what do the D and A wires go to? Link to comment Share on other sites More sharing options...
Ωhm Posted October 13, 2019 Share Posted October 13, 2019 88 Electrical Manual Click on and download the above link. Once downloaded, open file (.pdf). We need to get on the same page. Link to comment Share on other sites More sharing options...
Warren Mohler Posted October 13, 2019 Share Posted October 13, 2019 22 hours ago, ComancheFan said: 1 hour ago, ComancheFan said: Ok. So I'm missing a wire for the D and A plug on the C236. The bare wires were to the radio. I just put butt connectors in the place. And I did the same where the harnesses have been cut into. In the c236 plug what do the D and A wires go to? D is 12 volt input A goes to AC low pressure switch Link to comment Share on other sites More sharing options...
ComancheFan Posted October 13, 2019 Author Share Posted October 13, 2019 Ok, I don't believe I have a low pressure switch. Someone has changed quite a lot of my original cooling system. I'll send pics if what I have when I get home. Link to comment Share on other sites More sharing options...
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