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Jeep-Short Wheelbase All discussion of short wheelbase Jeeps: CJ, TJ, YJ and JK

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post #1 of (permalink) Old 09-10-2006, 03:28 PM Thread Starter
 
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vacuum operated duct door what? (update w/pic)

Hey all...

The cables that operate the vent/heater/etc... in my YJ eventually got stubborn enough to bend the wire. After straightening out the wire, I took a look at the plastic piece-o-junk that serves as the YJ's stock ventilation control and watched it flex all over the place when I tried to operate the levers. If I had assembled it back stock, it was gonna break. Like yesterday.

Anyway... decided to go with the CJ style cables and fab up something on the dash. I'll post pics when done. But right now I'm looking at this vacuum-operated plunger mounted on the fresh air intake ducting that pushes and pulls on a bellcrank that disappears in the duct roughly right above the glovebox. The vacuum line was routed to a plastic (of course) switch on the back of the dash control assembly that looks like it was depressed when the selector was in "off" and maybe half-depressed when the selector was in "defrost".

Does anybody have any idea what the purpose of all this was? I'm guessing there is a door in the ducting that is operated by the bellcrank, but why is it linked to vacuum? And what does it do? If I just disconnect it, which position should I leave it in? Should I rig a way to still operate it?
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post #2 of (permalink) Old 09-10-2006, 05:07 PM
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Re: vacuum operated duct door what?

cant give ya a direct answer on your application, however my old '88 K5 blazer had its' vac door fail, and the defroster was basically useless for three years as i tried to successfully remove three units from parts rigs(plastic can be so brittle sometimes[img]/ubbthreads/images/graemlins/frown.gif[/img]), i ended up just wiring it into place so air would come out the defrost and dash vents only...PITA

be carefull, i cant imagine the jeep version will be easier to work with
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post #3 of (permalink) Old 09-10-2006, 06:46 PM
 
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Re: vacuum operated duct door what?

I don'tknow about YJ's but on a CJ it will either compleatly cut off the fresh air from coming in, allow air to enter the heater duct or open the vent on the driver side ans passenger side to allow fresh air into the jeep.

Here is what a CJ cable connects too.
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post #4 of (permalink) Old 09-10-2006, 10:44 PM Thread Starter
 
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Re: vacuum operated duct door what?

Ummm... the vacuum rig in my YJ looks a tad different (see attachment).
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post #5 of (permalink) Old 09-11-2006, 04:46 AM
 
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Re: vacuum operated duct door what?

[ QUOTE ]
Ummm... the vacuum rig in my YJ looks a tad different (see attachment).

[/ QUOTE ]

That's what I mean, If your putting CJ cables in to replace it, a CJ is a little more complicated but your YJ looks like it only shuts a door inside.

Looks like it will be easier for you than what I have to put up with. You will have to leave the door open to heat your jeep. Actually I never shut mine so I guess you can leave it open all the time.
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post #6 of (permalink) Old 09-11-2006, 09:58 AM
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Re: vacuum operated duct door what?

I believe it's the defroster....
If the dash mounted switch still works...then leave it.
post #7 of (permalink) Old 09-11-2006, 10:02 AM
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Re: vacuum operated duct door what? (update w/pic)

If you're going to the all that trouble to cobble up a push/pull cable system for the heater box, you may be better served by swapping in a whole CJ Dash/heater box assembly.


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post #8 of (permalink) Old 09-11-2006, 11:07 AM Thread Starter
 
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Re: vacuum operated duct door what? (update w/pic)

Have seriously tossed around the idea, Larry... two things are hanging me up from getting over the hump: 1) I like having a defroster that works and haven't seen many examples of flat dash system substitutes. I haven't been impressed with the looks of the ones I have seen. And 2) the wife likes the YJ dash. [shrug] I'm just having trouble justifying spending more money and time on a solution that doesn't defrost well and that my wife doesn't like. We're out in the Jeep together a LOT.

I'm pretty much done cobbling up the brackets to hold the CJ cables. It really wasn't that bad. I'll try to post pics tonight. Now I just need to cut some holes in a plate to go on the dash for the control handles and I'll be good to go.

By the way... I'm toying with the idea of replacing the factory fan 3 speed selector with one that includes an "off" position. As of right now, I'll have to put in an on/off button for the fan separate from the speed selector. Does anyone have any pointers for a good source for an automotive off/low/medium/high switch?
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post #9 of (permalink) Old 09-12-2006, 10:49 PM
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Re: vacuum operated duct door what? (update w/pic)

[ QUOTE ]
Does anyone have any pointers for a good source for an automotive off/low/medium/high switch?

[/ QUOTE ]

Why not a CJ fan switch? It has those positions.
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post #10 of (permalink) Old 09-13-2006, 04:47 AM
 
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Re: vacuum operated duct door what? (update w/pic)

[ QUOTE ]
[ QUOTE ]
Does anyone have any pointers for a good source for an automotive off/low/medium/high switch?

[/ QUOTE ]

Why not a CJ fan switch? It has those positions.

[/ QUOTE ]

Yep, and real easy to hook up in a YJ.
http://www.quadratec.com/products/55412_03.htm

Also check with NAPA.
http://www.napaonline.com/masterpages/NO...er+Motor+Switch

A lot cheaper...
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