c00lkatz Posted October 31, 2011 Share Posted October 31, 2011 (edited) I have a strange problem on my '92 Pathfinder. My cigarette lighter fuse keeps blowing. I can use it a couple times, no problem. Then suddenly my A/C compressor stops kicking on. I went through the FSM and troubleshot everything from the A/C switch to the A/C relay and no problems except when the cigarette lighter fuse blows. I can use the cigarette lighter a few times, and then suddenly no A/C. It doesn't even happen instantly. I can use the cigarette lighter just fine for about 3-4 times, no problem, and then the fuse suddenly blows (while not even using it!). Check the fuse (15A) and it's blown. Change the fuse and no problems until I use the cigarette lighter a couple times. I'm mostly curious as to why this keeps my A/C compressor from clicking on. As far as I know, the two circuits shouldn't even be connected. I have checked for loose or frayed wires with no success. Everything looks like it should be good. Will I just have to let the cigarette lighter be just to keep my A/C going? Just posting here so maybe someone with some experience can shed some light on the problem. Anyone experienced this before? Edited October 31, 2011 by c00lkatz Link to comment Share on other sites More sharing options...
Slartibartfast Posted October 31, 2011 Share Posted October 31, 2011 That's odd. My first thought is that somebody messed with the wiring, couldn't find where to hook up the A/C, and hooked it to the cigarette lighter instead. If there's an AC fuse (I honestly don't remember)... is it good? When the cig lighter fuse is good, can you pull the AC fuse and have it still run? Link to comment Share on other sites More sharing options...
Kingman Posted October 31, 2011 Share Posted October 31, 2011 Check out some wiring diagrams and see if there's a common between the two, then check it. Short or ground usually if fuses are popping. Link to comment Share on other sites More sharing options...
c00lkatz Posted November 2, 2011 Author Share Posted November 2, 2011 That's odd. My first thought is that somebody messed with the wiring, couldn't find where to hook up the A/C, and hooked it to the cigarette lighter instead. If there's an AC fuse (I honestly don't remember)... is it good? When the cig lighter fuse is good, can you pull the AC fuse and have it still run? I didn't think of that. Yeah, the A/C fuse is good, but I never tried removing it when the lighter fuse is good to see if it still functions. That may be a good place to start looking for a short. I'll have to check that out. Link to comment Share on other sites More sharing options...
c00lkatz Posted November 4, 2011 Author Share Posted November 4, 2011 That's odd. My first thought is that somebody messed with the wiring, couldn't find where to hook up the A/C, and hooked it to the cigarette lighter instead. If there's an AC fuse (I honestly don't remember)... is it good? When the cig lighter fuse is good, can you pull the AC fuse and have it still run? Ok, checked this out, and it will not run without the A/C fuse OR the cigarette lighter fuse. They both have to be in/good for the A/C clutch to kick on. Check out some wiring diagrams and see if there's a common between the two, then check it. Short or ground usually if fuses are popping. That's the next step. Guess I have some studying to do Link to comment Share on other sites More sharing options...
Alkorahil Posted November 4, 2011 Share Posted November 4, 2011 Ok, checked this out, and it will not run without the A/C fuse OR the cigarette lighter fuse. They both have to be in/good for the A/C clutch to kick on. This made me give a baffled blank stare for a few seconds followed by me reaching for my copy of the FSM....... I would suspect, as pointed out above that someone in the vehicles past got creative with the power supply. Out of curiosity, what are you plugging into the cig lighter? BTW where in DFW are you? Link to comment Share on other sites More sharing options...
c00lkatz Posted November 6, 2011 Author Share Posted November 6, 2011 This made me give a baffled blank stare for a few seconds followed by me reaching for my copy of the FSM....... I would suspect, as pointed out above that someone in the vehicles past got creative with the power supply. Out of curiosity, what are you plugging into the cig lighter? BTW where in DFW are you? Yeah it makes no sense to me either. It could be a short I guess, which is probably what's causing the lighter fuse to blow in the first place. I don't know, haven't felt like ripping the dash apart AGAIN to look at it. I just have a regular cigarette lighter in there, no adapters or anything. I have the lighter sitting in there now and it doesn't blow or anything, only after I've actually used it a couple times. I am in Richardson a couple miles down the road from TX-190/George Bush & Renner. Link to comment Share on other sites More sharing options...
Alkorahil Posted November 9, 2011 Share Posted November 9, 2011 Yeah it makes no sense to me either. It could be a short I guess, which is probably what's causing the lighter fuse to blow in the first place. I don't know, haven't felt like ripping the dash apart AGAIN to look at it. I just have a regular cigarette lighter in there, no adapters or anything. I have the lighter sitting in there now and it doesn't blow or anything, only after I've actually used it a couple times. I am in Richardson a couple miles down the road from TX-190/George Bush & Renner. I went through the wiring diagram and components looking for something in common..... Are there any stray wires from the radio harness, or has it had an amp bypass done? (IE is it the stock radio still?) the radio harness goes up and ties onto the cigarette lighter and then that harness goes to the AC control switch. Think of the subharnesses comig off the main harness under the dashboard as a drop down tree: AC switch->cigarette lighter->Radio&radio amp. The ground and the constant power are coming down off the main harness. So something is grounding out intermittantly off this drop down. Link to comment Share on other sites More sharing options...
c00lkatz Posted November 9, 2011 Author Share Posted November 9, 2011 (edited) I went through the wiring diagram and components looking for something in common..... Are there any stray wires from the radio harness, or has it had an amp bypass done? (IE is it the stock radio still?) the radio harness goes up and ties onto the cigarette lighter and then that harness goes to the AC control switch. Think of the subharnesses comig off the main harness under the dashboard as a drop down tree: AC switch->cigarette lighter->Radio&radio amp. The ground and the constant power are coming down off the main harness. So something is grounding out intermittantly off this drop down. Hmmmm, I'll have to take a look at my wiring again. There was already an aftermarket head unit installed. Luckily they used an adapter instead of cutting the factory harness, but it was just twist-tied together with electrical tape and the rear speakers didn't work because they didn't hook up the remote turn-on for the factory rear speaker amp. I installed a new head unit (the one they installed was from like 2002) using the adapter and solder/heatshrink, and I rewired the factory amp harness to bypass it. I was able to tidy up as much stray wiring as possible, but I may have missed something. Come to think of it, my cigarette lighter hasn't worked since I got it, but it never kept the A/C from working. I only started having this issue after I installed the radio, so I must have screwed something up digging around under the dash. Thanks for the input! Edited November 9, 2011 by c00lkatz Link to comment Share on other sites More sharing options...
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