Dzimm Posted October 25, 2017 Share Posted October 25, 2017 On my 97+ truck I recently noticed smoke coming out of the Defrost vents on the dash (side vents only) after driving it for a little while. It doesn't smell like anything at all, doesn't seem to matter if it is hot or cold outside, and is so little smoke that you can barely see it when the truck isn't moving. It doesn't get any worse as time goes on either, it stays the same amount of smoke the entire time. My first thought was a leaking heater core but I have dry floors and even the drain valve in the engine bay never seems to be wet. The blower motor is a little noisier than my XJ but it seems to work just fine. Any ideas? Edit: forgot to mention that when the blower motor runs, the smoke goes away. It's only there when the blower is completely off. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 25, 2017 Share Posted October 25, 2017 I once had rodents packing stuff on the blower motor resistor..... Link to comment Share on other sites More sharing options...
Dzimm Posted October 25, 2017 Author Share Posted October 25, 2017 In that case I should probably pull everything apart.... It's just weird it doesn't smell like anything. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 25, 2017 Share Posted October 25, 2017 I didn't have to. You have the 97 and later dash? Link to comment Share on other sites More sharing options...
Dzimm Posted October 25, 2017 Author Share Posted October 25, 2017 Yeah I do but I'm worried about the noise in the blower motor. I'm thinking there may be crap in the hvac box. I'll pull the resistor and blower motor out when I get time and look around for anything. Link to comment Share on other sites More sharing options...
Green Mesa XJ Posted October 25, 2017 Share Posted October 25, 2017 May just be crap burning off, heater core leak can look similar but should have distinct smell. At least as I remember it. Sent from my iPhone using Tapatalk Pro Link to comment Share on other sites More sharing options...
cruiser54 Posted October 25, 2017 Share Posted October 25, 2017 Rodent nest in blower motor cage? That's what mine was. Link to comment Share on other sites More sharing options...
NC Tom Posted October 25, 2017 Share Posted October 25, 2017 3 hours ago, cruiser54 said: Rodent nest in blower motor cage? That's what mine was. Don't have that issue, but I had a Honda CRX years ago that had a mouse baked to the valve cover. I can't be sure, but that car seemed a bit sluggish after that! Link to comment Share on other sites More sharing options...
kryptronic Posted October 26, 2017 Share Posted October 26, 2017 This happened on my YJ. The cowl drain was clogged and when the heater was turned on the trapped water turned to steam. Link to comment Share on other sites More sharing options...
Dzimm Posted October 26, 2017 Author Share Posted October 26, 2017 7 minutes ago, kryptronic said: This happened on my YJ. The cowl drain was clogged and when the heater was turned on the trapped water turned to steam. I'll check that too. See whats weird is that even if I don't turn the blower on at all it still smokes after a while. Link to comment Share on other sites More sharing options...
kryptronic Posted October 26, 2017 Share Posted October 26, 2017 43 minutes ago, Dzimm said: I'll check that too. See whats weird is that even if I don't turn the blower on at all it still smokes after a while. I mentioned it because I had a similar problem that I feared was catastrophic, and turned out to be caused by 25 years of dirt accumulated in a plastic drain tube. When it happened to me, it was a distinctly white cloud of what I thought was smoke. I feared something caught fire. No smell, obviously, it was steam. Link to comment Share on other sites More sharing options...
cruiser54 Posted October 26, 2017 Share Posted October 26, 2017 Look here: Link to comment Share on other sites More sharing options...
Dzimm Posted October 26, 2017 Author Share Posted October 26, 2017 43 minutes ago, kryptronic said: I mentioned it because I had a similar problem that I feared was catastrophic, and turned out to be caused by 25 years of dirt accumulated in a plastic drain tube. When it happened to me, it was a distinctly white cloud of what I thought was smoke. I feared something caught fire. No smell, obviously, it was steam. Yeah I'll have to look into it. It would make sense to be some kind of steam. I don't remember it condensating on my hand or anything when I was first investigating it. Did it condensate for you? Link to comment Share on other sites More sharing options...
kryptronic Posted October 26, 2017 Share Posted October 26, 2017 7 hours ago, Dzimm said: Yeah I'll have to look into it. It would make sense to be some kind of steam. I don't remember it condensating on my hand or anything when I was first investigating it. Did it condensate for you? Not that I recall. It didn't fog the windows up either. Link to comment Share on other sites More sharing options...
moparbrown Posted February 2, 2018 Share Posted February 2, 2018 I had a similar thing happen in my 91. I first noticed it once daylight savings hit and thought it was my headlights smoking. I tore my dash half apart and drove around like that for a couple weeks to try to find the source but never did. I haven’t noticed it smoking for awhile so I’m not sure if it was the headlights or heater but I keep a fire extinguisher in the truck now. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
Eagle Posted February 2, 2018 Share Posted February 2, 2018 On 10/25/2017 at 7:25 AM, cruiser54 said: I once had rodents packing stuff on the blower motor resistor..... Only once? I should be buying those resistor packs by the case. And, yes -- when the little rascals build their nest in there, it does create smoke and a burning smell. For awhile -- then the thermal fuse pops, and you have a single-speed fan -- it's either off, or high speed, nothing in between. Link to comment Share on other sites More sharing options...
moparbrown Posted January 15, 2019 Share Posted January 15, 2019 I had a similar thing happen in my 91. I first noticed it once daylight savings hit and thought it was my headlights smoking. I tore my dash half apart and drove around like that for a couple weeks to try to find the source but never did. I haven’t noticed it smoking for awhile so I’m not sure if it was the headlights or heater but I keep a fire extinguisher in the truck now. Sent from my iPhone using Tapatalk Update: Seems as though it was my “headlights”. The switch that controls them was burnt up and melted inside and my headlights eventually stopped working. DIY writeup here- https://comancheclub.com/topic/57308-headlights-not-working-solution/Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
cruiser54 Posted January 15, 2019 Share Posted January 15, 2019 Good to hear you found it. did the harness then? Link to comment Share on other sites More sharing options...
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