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Blower Motor and Blend Door vacuum(?) not working

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Old 07-11-2021, 03:40 PM
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Default Blower Motor and Blend Door vacuum(?) not working

I am sure we have all had our share of A/C problems in the XJ ... nothing new there. Whether it's the evap or heater core, relays, fuses, electric fan up front or whatever.

Well, today, folks, I present you with the magnum opus of haywire A/C problems I've ever encountered in these things. I am stumped.

This is on a 2000 (built in 08-99) XJ with a 4.0L.

Blower Motor gradually stopped working over a period of about a week. Currently it does not work at all, and even the ***** for switching where the air blows doesn't make any noise like it normally does.

Now, what have I done to try and remedy this?
Some google searching does bring me to a few videos about a blower motor relay behind the glove box and another addressing the resistor. Great! I replaced those, still no good.

I found a few threads on the forum here even explaining in GREAT detail some other problems: Here, where user TestPoint explains. and here and here
Trying these methods still hasn't solved it.

I replaced the blower motor, which didn't even look bad at all. Still nothing.
Then I thought it might be the unit those control ***** sit on. I went and bought a new one, still nothing.
There are no blown fuses or relays.

I'm not even sure where to begin with the vacuum actuated doors. I am not finding any cracks in the vacuum tubes anywhere.

When I switch to the A/C setting compressor turns on like normal.

What gives??
Old 07-11-2021, 06:17 PM
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Sorry you spent money on parts. Your description of the problem does not point to any of those.

Sounds like a vacuum leak, which you often cannot detect with the naked eye. You need a smoke test, or some other method. Lots of good videos on YouTube about finding vacuum leaks. That's where I'd be going.
Old 07-20-2021, 01:06 PM
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mine just blows cold air out the wrong places (def and floor instead of dash) HELP
And i dont know how to do forum !!!!!!!!!!!
1998 GC sport
Old 07-22-2021, 10:43 PM
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Could not find a vacuum leak through a smoke test. Going to try testing continuity at some point later.

Could use some more ideas. This Jeep is in good shape and only 180k on the clock, but might just scrap it or part it out if I can't solve this. Driving this thing in the heat is no fun.
Old 07-25-2021, 03:52 PM
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Don't think a vacuum leak will keep the blower motor from working. It sounds like a electrical issue. Need to break out your test light or multi-meter and chase it down. With the switch on high, there should be voltage to the blower motor. If nothing there go back to the fan switch. Should be a hot coming into the fan switch with a wire going out to the fan motor. If no hot coming in you back up to the fuse box and check there. All a motor needs is a ground and a hot. Might want to check your grounds (unbolt, clean and tighten) while you are messing with it. Jeeps like good clean grounds!
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