Interior Heater - What am I missing?

Interior Heater - What am I missing?

TrackRat

Jeeper
Posts
30
Thanks
4
Location
Bay Area CA
Vehicle(s)
1976 CJ-5 (3-spd / 304)
1976 CJ5

In the middle of a dash replacement / gauge upgrade. While everything is apart I figure I should take care of the missing components to the heater / ventalation system. I know the fresh air box is jacked (prior owner hacked it up to fit a stereo) - have a replacement on hand. I have all the cables to the dash. Seems like I am missing the defrost duct and the duct from the fresh air box to the heater box. Anything else obvious?IMG_0475.jpeg
 
Looks like you need the air duct from the right side of the fresh air box that then curves down to the heater assembly above the passenger's feet, with the two clamps. You also need the drain hose (with clamp and cap) and the defrost hoses/clamps. And do you have the defrost ducts under the dash? Can't tell from your pic. Optionally you may also want the diverter for the floor heat. While it's out anyway, a new heater core would be good. A common upgrade is to also replace the blower motor. For these earlier style units, the VDO PM322 works well. It's a bit larger and may require a slight mod to one corner of the glovebox, but no biggie.

air_assembly_early.jpg
 
The fresh air box drain is from the bottom of the fresh air box to a hole that is about 1 1/2" in diameter that should be visible just below your heater/air plenum, about 20-24" down from the bottom of the fresh air box and then into the firewall. It is slightly offset to the right of where the air box drain is so the hose doesn't necessarily go straight down. It exits under the battery tray. MTS sells the drain hose and cap that goes on it. Part # CJABH-1. Early CJ Air Box Drain Hose

They also have the duct hose from the air box to the heater assembly, with the clamps. Part # CJABFAH-1. Early CJ Duct Hose
 
If you have a pop rivet tool, remove the bracket from the old box and put it on the new one. Or, since the top is accessible (open where you can get your hand in there), just drill out those existing rivets and use a pair of small screws with lock nuts on the inside to mount the bracket. I wouldn't mess with trying to jerry rig a way to secure the cable to a bracket not made for it.
 
The fresh air box drain is from the bottom of the fresh air box to a hole that is about 1 1/2" in diameter that should be visible just below your heater/air plenum, about 20-24" down from the bottom of the fresh air box and then into the firewall. It is slightly offset to the right of where the air box drain is so the hose doesn't necessarily go straight down. It exits under the battery tray. MTS sells the drain hose and cap that goes on it. Part # CJABH-1. Early CJ Air Box Drain Hose

They also have the duct hose from the air box to the heater assembly, with the clamps. Part # CJABFAH-1. Early CJ Duct Hose
Thanks for the lead on the Duct Hose. Had ordered what I thought was the right part from Summit but was way too short. Used the link provided to grab one from 4x4partsdude.com who were super helpful.

Another Q… what (if anything) does the opening to the right of the outlet for the defrost hose connect to?
 
There are actually two defrost hose connections on the top. The right one is hard to use due to the drain hose. So many people just cap off that right one and just use a single defrost hose on the left with a funnel shaped defrost duct like in the pic I posted.
 
Perfect. Just installed a duct similar to the one in your picture yesterday. Prior owner had a jelly jar top over the second opening. I’ll give it a nice coat of black paint and call it a day then. Thanks again!
 

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