Wagoneer HVAC Issues - JeepForum.com

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post #1 of 3 Old 10-19-2011, 05:19 PM Thread Starter
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2006 TJ Wrangler 
Join Date: Aug 2011
Location: Columbus
Posts: 77
Wagoneer HVAC Issues

Hey guys!

I'm having some issues with the HVAC system on my 1973 6-cylinder Wagoneer, and was wondering if anyone here would have any insight into the problem.

As recently as a couple months ago, everything appeared to work correctly. The heat would blow hot, and the fan would, well, it would circulate the air at least. Now, when I turn on the fan, I get nothing out of any of the vents (that is, the defroster vents under the windshield and the heater behind the gearshift, under the dash). I checked the blower motor and it is working fine.

I have two ideas for what it could be. 1) Something is clogging the HVAC hoses behind the dashboard. This is plausible because my Jeep sat dormant for 20 years before I bought it. However, since the fan blew air in the cabin when I bought it, I feel like this is not the problem. 2) The buttons to control whether the HVAC is off, on heat mode, or on defrost mode might be sticking, causing the hoses to all be closed. This is possible I believe, but does anyone have some sort of diagram that shows how those buttons actuate their respective controls? I'm not sure how it works and I'd like to have some idea before I start tearing apart the dash.

Has anybody else run into problems like this before? Any suggestions or insight is much appreciated. By the way, the Jeep doesn't have air conditioning. Thanks everyone!

1997 Honda Prelude - "Kiera"
2006 Jeep Wrangler X - "Gretchen"
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post #2 of 3 Old 10-20-2011, 10:24 PM
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1973 FSJ Wagoneer 
Join Date: May 2006
Location: Reno, NV
Posts: 11,246
My system was working fully, but I have torn into it several times.

At the VERY LEAST I would pull out the instrument panel and replace all the vacuum lines (4, 1 coming in and 3 going out i belive) behind the dash. It's pretty easy.

Loosen the 2 bolts under the steering column to drop it, then reach up and unscrew the speedo cable...then remove the screws holding in the gauge cluster, then slide it out (you need to rock the right side out first, because the hoses for the HVAC stick out a little bit on the left). You'll need to disconnect the wires for the ammeter, then remove the plug for the gauge wiring.

Replace the vacuum hoses, as said that part is easy. remove and clean the switches for the HVAC, it comes right out. Mine was nasty and gummed up but with a little parts cleaner and some elbow grease it functions great now.

While you are in there take a dremel and wire brush to the connectors on the wire and on the gauge for the amp meter. That is a HUGE cause of electrical fires in these old jeeps, as it gets corroded...corrosion = heat...heat = fire. If you clean it up you SHOULD be fine, but be aware that ALL of the current from the alternator passes into the cabin, through that lil bitty gauge, and then back out to charge the battery and power the truck. Many people will bypass this, or at the very least take the two wires and put them on the same terminal on the meter, to minimize the resistance and bypass the meter.

Good luck, its easy and alot of fun. Post up some pictures of your 73, I have one too!


Illegitimi Non Carborundum

The Beast Build Thread: Marns '73 Wagoneer Thread ----- The Camper Build Thread: Marns 1980 Jayco JayFinch6 Build Thread

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post #3 of 3 Old 11-12-2011, 07:26 PM Thread Starter
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2006 TJ Wrangler 
Join Date: Aug 2011
Location: Columbus
Posts: 77
Post up some pictures of your 73, I have one too!
Thanks a lot for the help! Take a look at My Jeeps, I just figured out how to post pictures of my rig there.
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