Another CJ heater question

[broncojeep]

Hi guys, new to the site, but did try to read all of the other posts related to heaters. I saw the picture/diagram posted by Elwood - good stuff. I've had my CJ for 10 years and the heater has never really done well, it certainly doesn't defrost. The cables were not attached when I bought it, so I bought new ones and did the best I could to connect them, but have never been sure they were working properly. In fact, I don't know if any of the door flaps are in the correct position or how to change them. The Haynes manual is not very useful in helping me to understand where everything belongs. I had the blower motor replaced the first week I owned it by a shop and they said they put in an upgraded motor, but beyond that I am not sure. When the heat is on, it is minimal and seems to die off pretty quickly. Can anyone direct me on where to get a more complete breakdown of where everything should be positioned so I at least have a good starting point to diagnose how it can be improved? Thanks

 

[gillmore]

Jeep Informational Center at Morris 4x4 Center

Go to the Online Repair Manuals-->CJ7 -->1982-->Body Heater

Page 2 has an exploded diagram that may also be useful. You can print these pages out (off Flash viewer).

The fresh air cable is connected in 2 parts - one that goes from the pull-control knob to a connecting lever + rod (accessible from behind the glovebox). It controls the vent trap door on the hood (is yours stuck open possibly?). From there, another cable connects to the vent door inside the jeep. This one has an adjuster that you can hand-turn to make sure the inside vent door is fully closed when it should be.

The temperature and heater/defrost leavers are pretty straightforward. You might disconnect the cables on these (just remove the retaining clips and pull the loop off) and hand adjust to find the hot/cold/heater/def positions.

Glen

 

[elwood blues]

Hi guys, new to the site, but did try to read all of the other posts related to heaters. I saw the picture/diagram posted by Elwood - good stuff ~ ~

Welcome to the site broncojeep :ww:

Another thing to check, the defroster duct, going from the heater plenum to the defroster. If you have an aftermarket radio in the factory radio hole, the aftermarket radio is longer than the stock radio so it will crush the ducting closed (I know from experience ).

 

[gillmore]

I struggled replacing the flexible heater duct a few months ago. The paper one that was in there had turned to dust and was just a wire skeleton. I ended up pulling my radio to get in there and clamp the duct down. Although I was able to get my radio back in and flush mounted to the dash, you might want to get a spacer (trim ring) from your local car stereo place or crutchfield.com if you need more space for the duct.

 

[Thew]

I struggled replacing the flexible heater duct a few months ago. The paper one that was in there had turned to dust and was just a wire skeleton. I ended up pulling my radio to get in there and clamp the duct down. Although I was able to get my radio back in and flush mounted to the dash, you might want to get a spacer (trim ring) from your local car stereo place or crutchfield.com if you need more space for the duct.

My heater was real weak in my 82 CJ7 , I pulled the whole heater box out and ended up swapping it with another one I had. The fresh air valve was broke in mine letting in cold air. its not hard to get the whole thing out, you pull back the dash and its easy to get to.
I cleaned out the new one and removed and cleaned the core. there was years of dirt build up on the core.
I have good defrost now and heat when I need it .

 

[broncojeep]

Thanks for all the advice guys, I really do appreciate it. I've been messin with this thing this afternoon and understand the make-up of it a little better. What I am seeing is that the linkage on the 'heat-vent' cable isn't necessarily sized up, but it doesn't move easily or very far and I can't even get all the pieces into the configuration shown on the picture from Elwood. Does someone understand how that all is supposed to work?

 

[Cheepjeep85]

the best thing you can do is put a k5 blazer blower motor in it. that being said if you decide to do that, when you pull the box you should take some time reconditioning the box, when i pulled mine every flap in the box was bent and out of place, (don't know how they got that way) and it was causing the cables to not move them correctly, or letting them seal up in side the box as they should be, i actually had to tack weld one of the shafts that runs through the fresh air flap to get it to turn. also they defrost/floor flap was bent not allowing the full amount of airflow up to the defrost. another thing that helps is spraying a small amount of white lithium grease in the pivots for each flap, and especially on the linkages on the top and sides of the heater box, and anywhere the cables connect. just some things to look for, remember its probably been heavily used for the last 30 years, things wear out.

 

[jeffgtoman]

Don't forget about the heater core end of it. Here's a couple things to check. With the engine running on fast idle and warmed up, grab the hoses going into the heater core. They both should be about the same temperature. They should be pretty hot, almost too hot to hang on to. If one is hotter than the other, your heater core is plugged and has no coolant flowing thru it. If they are lukewarm, you probably have a leaking thermostat.
This last test is something I haven't tried on my Jeep yet but when I have repaired heaters on average cars and oick-ups, I use 120 degrees as my go no-go point. If I can't get more than 120 degrees air temp out of the heater vent, I know there is something wrong. Maybe a heater core plugged or a blend door stuck.

 

[broncojeep]

Thanks again to everyone for the advice - it was all helpful.

I ended up replacing the heater core (holding both hoses was a great diagnosis for that problem that I was not aware of).

I also ended up removing the entire fresh air duct to try and figure out why the vents wouldn't open properly. The primary problem was the linkage and the vent door on the passenger side. I compared my linkage to a couple of other CJs at a local shop that works exclusively on Jeeps and we found that mine was not operating as it should. Then I took the whole assembly to a local used Jeep parts place - he found an old one up on the top shelf and the linkage on it seemed to be working better - so I bought it.

My paper duct was in great shape until I tried to remove the fresh-air duct, so I had to buy a new one of those also.

After much debate and patience trying to do something I had not done before, everything eventually got re-installed. The removal of the entire heating system gave me the "opportunity" to try and make sense of the maze of wires under my dash and clean things up a bit. Both myself and the PO have done numerous electrical modifications and it was really hard to determine where anything went.

I took a long drive last night and for the first time in over 10 years, my Jeep has heat! And I thought it was just normal for the older Jeeps to only have an initial burst of heat followed by luke-warm air. I can't wait for frost on the windshield to see how the defroster works.

Thanks again everyone!