wranglercory Posted May 30, 2008 Share Posted May 30, 2008 I have just recently purchased a 1987 MJ with a 2.5 and a 5 speed in it. I decided to charge the air cond. in it and realized that when I move the heat/ac switch to on it doesnt blow out at all. I know that there is probably a vacume switch somewhere but I'm not sure where. Does anyone know where the switch is located? A picture would be best if you have one. Thanks for your help. Link to comment Share on other sites More sharing options...
Pete M Posted May 30, 2008 Share Posted May 30, 2008 Is the fan not working? or is the air only coming out the top windshield defroster vents? Link to comment Share on other sites More sharing options...
fiatslug87 Posted May 30, 2008 Share Posted May 30, 2008 If it only blows through the defrost vents it's probably the vacuum line. There should be a vacuum canister in the front bumper on the passenger side. Trace the small hard line and check for cracks, usually where it runs by the battery. That's where I found the problem in two of my MJs. Link to comment Share on other sites More sharing options...
wranglercory Posted May 31, 2008 Author Share Posted May 31, 2008 The fan is blowing but there is no air coming from any vents. The fan is working but something is not allowing it to blow through the vents. I will check the canister tomorrow. You can feel a little AC from certain places but nothing from the vents. Thanks Link to comment Share on other sites More sharing options...
Pete M Posted May 31, 2008 Share Posted May 31, 2008 You're sure that nothing is coming out the top by the windshield? Maybe the big flapper door is stuck shut. Does that let in the fresh air? I remember screwing around with it before in my 88, but don't remember why. A screwdriver stuck through the the hole down by the passenger's feet freed it up. Link to comment Share on other sites More sharing options...
mrsinister Posted April 16, 2010 Share Posted April 16, 2010 Holy open new thread batman! But seriously, i used my search function... If i only have air coming out of my top defroster vent but not the other vents, than this is attributed to a vacuum line from a canister in the front bumper? just checking before i dissasemble my dash. thanks! Link to comment Share on other sites More sharing options...
Pete M Posted April 16, 2010 Share Posted April 16, 2010 it means you might have a vacuum leak. the leak could be anywhere in the system. the vacuum canister is a common failure point and a good place to start. :thumbsup: Link to comment Share on other sites More sharing options...
Harper Posted April 16, 2010 Share Posted April 16, 2010 :hijack: Plz excuse the ol' grampa story, but I once had a problem exactly like the one described. Fan worked just fine but no air came out at all.....ended up opening the hood and pulling the blower.... found a mouse had built himself a home in there......stuffed the sucker full of pink fiberglass insulation it had picked up elsewhere in the building. I was driving an 18 wheeler at the time, and was gone a lot, so the Manche wasn't getting much use. But it was always closed up, windows and all. I even had to run a wire down the condensation drain tube to get all the insulation out of there. Never could figure out how the little bugger got in...... :hmm: Link to comment Share on other sites More sharing options...
ParadiseMJ Posted April 16, 2010 Share Posted April 16, 2010 I had a mouse...evidenced by mouse poo AND the insulation, sticks and cardboard bits stuffed in my housing...set a trap...caught the mouse but I have yet to clean out the ducts, blower etc. It was a farm truck before I got it and was sitting in the guys barn. Mice are industrious little buggers. Link to comment Share on other sites More sharing options...
MJ is dead Posted April 16, 2010 Share Posted April 16, 2010 I'm with the clogged vents theory. My nissan had vents on the hood for air exchange, and every fall or winter I would have to pop the vents off and clean the crap out of there, or I got no heat Mice can really crap on your tea party. I bought an old datsun pu from a farmer who couldn't figure out why it was running rough. Turned out a mouse had built a nest between the carb and air cleaner. Problem solved Link to comment Share on other sites More sharing options...
Pete M Posted April 16, 2010 Share Posted April 16, 2010 also could be that the diverter is stuck. Had that happen too. used a screwdriver to push it free. Link to comment Share on other sites More sharing options...
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