New Member w/ HVAC Question - JeepForum.com
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post #1 of 27 Old 03-03-2018, 06:34 PM Thread Starter
BigSky2000
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New Member w/ HVAC Question

New Jeep owner of 3 weeks now and new member of this forum. We bought a 2000 TJ that lived in Wyoming and has now moved to Montana. It is in great shape and seems to have been well taken care of. We had been looking for a Wrangler for several months and most of what I had learned about the good, bad and ugly came from this forum. Thanks to everyone who participates here and makes it such a great resource.

Now the question - why does the heater fan only work on some mode settings ? The Jeep has air conditioning and everything HVAC is perfect if the A/C is seleted - max, min, or either defrost. But select either vent setting and no fan operation. By perfect I mean just that - correct damper positioning, 4 fan speeds, and the heat will drive you out. On the vent settings the damper moves and selects the asked for position but the fan doesn't run at any speed. I have the FSM for 2000 and the wiring diagram says this can't happen -- but it is. I have searched this forum (and other places) without finding this specific problem, but I have read about other HVAC problems.

Does anyone have any insight ?? Thanks for considering this question.


You must live in Montana if your sports car is a Jeep Wrangler !
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post #2 of 27 Old 03-03-2018, 06:45 PM
biffgnar
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Did you read about blower motor resistor?
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post #3 of 27 Old 03-03-2018, 07:05 PM Thread Starter
BigSky2000
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Yep -- but according to the wiring diagram there is only one path from the mode selector to the fan switch so I don't understand how it works fine on 4 out of the 6 modes -- wiring diagram wrong ?

You must live in Montana if your sports car is a Jeep Wrangler !
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post #4 of 27 Old 03-03-2018, 07:16 PM
biffgnar
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I've never had to deal with this issue, but I thought working on only some settings was stereotypical of the resistor issue.
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post #5 of 27 Old 03-03-2018, 07:23 PM Thread Starter
BigSky2000
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Yeh -- I figured this would be unusual since all 4 fan speeds work on 4 of 6 mode settings, so I figured the resistor was ok. I guessing its the mode selector switch, but I was hoping there might be another answer.

You must live in Montana if your sports car is a Jeep Wrangler !
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post #6 of 27 Old 03-03-2018, 07:23 PM
JEK3
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The mode selector switch can overheat and melt if the blower is drawing too much current. I'd recommend pulling the center dash off and removing the HVAC switch unit. Look at the back, from what I've seen in pictures, this condition should be obvious, and will require a new switch unit.
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post #7 of 27 Old 03-03-2018, 07:33 PM Thread Starter
BigSky2000
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That seems likely -- but it will have warm up before I can get enough motivation to go check it. Changing shocks in 40 deg. weather is more active then sitting and taking a dash apart ...

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post #8 of 27 Old 03-03-2018, 08:03 PM
JEK3
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I hear you! As long as you can find a switch combination that keeps you warm, everything's good, right?
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post #9 of 27 Old 03-03-2018, 08:39 PM Thread Starter
BigSky2000
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That's true -- it mostly works just fine. At some point I'd just like to get the A/C compressor to shut off.
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post #10 of 27 Old 03-03-2018, 09:08 PM
mukluk
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A short term solution to get the compressor to shut off until you can find and fix the blower issue would be to just pull the AC clutch relay or PDC fuse 21.

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post #11 of 27 Old 03-03-2018, 09:54 PM
TheBoogieman
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Quote:
Originally Posted by BigSky2000 View Post
That seems likely -- but it will have warm up before I can get enough motivation to go check it. Changing shocks in 40 deg. weather is more active then sitting and taking a dash apart ...
It takes 5 minutes to check it.

Quote:
Originally Posted by jeepinmichguy_ View Post
TheBoogieman is a jerk.
GOT IT BACK 6/17. 03' Rubicon/Zone 4.25" combo lift with 4" lift coils up front/Zone hydro shocks/5.13 gears/35" Mickey Thompson MTZ P3 tires/Black Magic brakes. Jeep #17 & 19.
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post #12 of 27 Old 03-04-2018, 07:36 AM
cthusker174
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Quote:
Originally Posted by JEK3 View Post
The mode selector switch can overheat and melt if the blower is drawing too much current. I'd recommend pulling the center dash off and removing the HVAC switch unit. Look at the back, from what I've seen in pictures, this condition should be obvious, and will require a new switch unit.
That's exactly what happened to my 99 Saraha. I needed to replace the blower motor which is what caused the melt down on the HVAC switch. It got damn hot cause it really melted wires, etc.

New switch, wires and blower motor and everything now works perfect. I would recommend checking out the blower motor to make sure it doesn't ruin a new HVAC switch.
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post #13 of 27 Old 03-04-2018, 02:02 PM
Rubi4MyMrs
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Have you checked the 3 wires on the mode switch? If so, does it have a connector or 3 individual wires? I’m betting 3 wires or possibly a replacement connector with the wires spliced into the original wires. If either of these conditions exist they probably have the wires in the wrong positions. The smaller gauge light green wire needs to be on the top (A) terminal, the heavier dark green in the middle & the black on the bottom (C) terminal. The smaller is the a/c compressor feed wire & the heavier is the fan wire. If the top 2 are reversed you will only get the fan in the a/c & defrost positions & the a/c compressor will be engaged in all positions except off.
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post #14 of 27 Old 03-04-2018, 02:29 PM
BubbleheadSS
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Quote:
Originally Posted by Rubi4MyMrs View Post
Have you checked the 3 wires on the mode switch? If so, does it have a connector or 3 individual wires? I’m betting 3 wires or possibly a replacement connector with the wires spliced into the original wires. If either of these conditions exist they probably have the wires in the wrong positions. The smaller gauge light green wire needs to be on the top (A) terminal, the heavier dark green in the middle & the black on the bottom (C) terminal. The smaller is the a/c compressor feed wire & the heavier is the fan wire. If the top 2 are reversed you will only get the fan in the a/c & defrost positions & the a/c compressor will be engaged in all positions except off.
This reply right here, thank you! This was the exact problem I had. Someone before me, must have had the dash apart and when the put the switch cluster back on, they put the wires on backwards. Check your wiring on the back of the cluster, saved me $100! Thank you!
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post #15 of 27 Old 03-05-2018, 10:47 AM Thread Starter
BigSky2000
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Thanks to everyone who has replied -- I think Rubi4myMrs may have hit it -- PO installed a Kenwood receiver, so there has been monkeying around behind the dash, who knows what may have happened. Also, if there is a blower motor problem how long does it take before the switch bits melt ?? I know there are other threads that discuss blower motors and I'll be checking those. The temperature is supposed to get to about freezing with sunshine, which is a big improvement so maybe I can get a look at this today.

Thanks again.

You must live in Montana if your sports car is a Jeep Wrangler !
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