Vanning.com logo
Boxdin
Site Navigation


Advertisements
Recent Posts
Crazy mods
by Wedgy - March 28th 2024 7:24 am
Good day
by SDMickey - March 27th 2024 10:55 pm
Lew Greger
by MufflerMan Mike - March 27th 2024 5:15 pm
1987 G20 Gypsy
by SDMickey - March 25th 2024 9:39 pm
Featured Links


Previous Thread
Next Thread
Print Thread
Rate Thread
Need help! 78 Tradesman AC and Heater issues
#714439 September 21st 2016 8:59 am
Joined: Sep 2016
Posts: 15
7
stranger
OP Offline
stranger
7
Joined: Sep 2016
Posts: 15
Hey again,

The more I look around, the more little stuff I find that needs attention.

The heater and AC appear to be 2 separate units but they are located in the same console. The heater/defrost is on top with its own fan control lever and beneath that is the AC which has a fan speed knob.

Heater issue: the sliding lever on the top is not securely fastened to the open/close lever on the box in the engine compartment. I think I can fix that myself by rigging it together. I hope that once I do that the lever on the inside unit slides easily because now it is very hard to slide.

I need to fix this for many reasons, but it would be nice to be able to stop the vent below the steering column by the doghouse from blowing hot air on me! It even blows hot air when the fan is off. Not much like when I turn the fan off, but some. Is that just the way that works?

Also, the top lever supposedly goes from cold to hot, left to right. Since I think this is only for the heater/ defrost unit does it ever really get "cold" or just the absence of "hot"?

AC issue: this is a bigger problem. The knob that appears to be the fan control that has off/low/medium/high used to work intermittently but only on high. Recently that knob just doesn't do anything. No response when I turn it. It appears intact and the wires behind it appear connected and ok. I need to fix this for sure BEFORE I get the AC system converted which I want to do.

How can I know if this is a fuse? My fuse box isn't labeled. Or the resistor? Or the blower motor? Can I repair this myself? I'm not that handy but willing to try.

Finally the unit is missing the knob all the way to the right that controls the temperature. I need that knob. I have looked on eBay and the classified section here. No luck. Anyone have an extra knob? I would prefer one that matches the other ones as the van is otherwise original.

I'm no mechanic. I've looked in YouTube for videos. No luck. If anyone here can help me through these issues I will buy you a cup of coffee when we ever meet! Pictures, videos, a simple how to would be great. My local dodge dealer didn't even want to look at the van!

Thanks again, and please help me find some knobs, or even an original combination heater/AC unit if I need it. I even tried looking for that and couldn't find one.

Dodger

Re: Need help! 78 Tradesman AC and Heater issues
78dodger #714474 September 21st 2016 10:46 pm
Joined: May 2006
Posts: 3,113
Likes: 2
pooh-bah
Offline
pooh-bah
Joined: May 2006
Posts: 3,113
Likes: 2
Not sure I can help but I used to have an 86 Dodge that had dealer installed a/c (sounds to me what yours might have). Not the same as factory a/c. Anyhow, mine also blew air on my feet. Even more when the window was open. Mine also never got that cool when lever was on the cold setting. Very annoying having warm air blowing on the feet. I always thought maybe it was something done wrong when the a/c was installed. I put a new heater core in it and thought maybe the door in the heater box was stuck open or something but it seemed ok to me. It could have been just flopping around in there though. I realize this isn't any help but I also had similar problems. As for the a/c questions I have even less answers, hopefully someone else has some answers.

Re: Need help! 78 Tradesman AC and Heater issues
78dodger #714486 September 22nd 2016 11:48 am
Joined: Aug 2001
Posts: 12,107
Likes: 37
Maniac
Offline
Maniac
Joined: Aug 2001
Posts: 12,107
Likes: 37
Originally Posted by 78dodger
Hey again,

The more I look around, the more little stuff I find that needs attention.


That is normal for a 38 year old vehicle.

Originally Posted by 78dodger
The heater and AC appear to be 2 separate units but they are located in the same console. The heater/defrost is on top with its own fan control lever and beneath that is the AC which has a fan speed knob.


Are you sure your van is not a 77? The system you describe sounds like the 71-77 Dodge HVAC assembly. In 78 Dodge vans switched to the 79-03 dash that has completely different HVAC controls and layout.

Originally Posted by 78dodger
it would be nice to be able to stop the vent below the steering column by the doghouse from blowing hot air on me! It even blows hot air when the fan is off. Not much like when I turn the fan off, but some. Is that just the way that works?


No. It sounds like you have a failed seal around the engine cover or in the HVAC system. You may need to disassemble the vents from the firewall and replace the gaskets. Otherwise hot air from under the hood will just bklow right in on you.

If the hot air is truly coming from a vent and not leaning in past a failed gasket you need to inspect the heater control doors and cables. The cables can bind not work right, the doors can get stuck in a position, the gaskets and seals on the doors can fail and let air leak past them, etc...

Originally Posted by 78dodger
Also, the top lever supposedly goes from cold to hot, left to right. Since I think this is only for the heater/ defrost unit does it ever really get "cold" or just the absence of "hot"?


Can you post a picture of the dash of your van?

Originally Posted by 78dodger
AC issue: this is a bigger problem. The knob that appears to be the fan control that has off/low/medium/high used to work intermittently but only on high. Recently that knob just doesn't do anything. No response when I turn it. It appears intact and the wires behind it appear connected and ok. I need to fix this for sure BEFORE I get the AC system converted which I want to do.


Sounds like a failing fan switch, failing plug for the fan switch, and possibly also a failed ballast resistor for the fan unit. You can try pulling the fan switch and cleaning the terminals with a contact cleaner and trying to clean inside the switch with contact cleaner, but you may just need a new switch.

Originally Posted by 78dodger
How can I know if this is a fuse? My fuse box isn't labeled. Or the resistor? Or the blower motor? Can I repair this myself? I'm not that handy but willing to try.


(1) check the fuse box for a blown fuse. (2) get a owner's manual or factory service manual for your van. You will need both (eventually) (3) You can diagnose and repair this yourself, but you need those manuals.

Originally Posted by 78dodger
Finally the unit is missing the knob all the way to the right that controls the temperature. I need that knob. I have looked on eBay and the classified section here. No luck. Anyone have an extra knob? I would prefer one that matches the other ones as the van is otherwise original.


Keep looking. Good luck.

Originally Posted by 78dodger
I'm no mechanic. I've looked in YouTube for videos. No luck. If anyone here can help me through these issues I will buy you a cup of coffee when we ever meet! Pictures, videos, a simple how to would be great. My local dodge dealer didn't even want to look at the van!


Not surprising. Your van was built before most Youtube users were.

Originally Posted by 78dodger
Thanks again, and please help me find some knobs, or even an original combination heater/AC unit if I need it. I even tried looking for that and couldn't find one.

Dodger


Like I say, keep looking for the knobs. you will find them eventually. In the meantime, try adapting a set of universal knobs.

It sounds to me like you would be wise to completely disassemble the HVAC system(s) in your can and go through them thoroughly. Clean them, replace all the gaskets and seals, clean all the elctrical connections, verify that the air doors are functioning correctly, verify that the control cables move freely, etc... You truly do need to get a factory service manual for your van.

Good luck!


Windows- they're what make a van worth owning!
Re: Need help! 78 Tradesman AC and Heater issues
78dodger #714525 September 23rd 2016 4:28 pm
Joined: Mar 2007
Posts: 4,463
Likes: 12
pooh-bah
Offline
pooh-bah
Joined: Mar 2007
Posts: 4,463
Likes: 12
I totally agree with Reed, your description doesn't exactly match what I'd expect on a 78 & up. Please post a couple of pictures. I'll give it a shot till then.

At the top of this picture are the factory AC/Heater and fresh air/recirculate/blower systems from the later vintage vans:
[Linked Image]



Do you have a voltmeter/ohmmeter? You should definitely be able to bring her back to life.


First off, based on your description, there is one possible way to cut down on at least some of the hot air you're feeling if your heater box has the normal type of control lever. Connect that cable! When you connect the cable to the lever at the top of the box, your hot/cold lever on the dash will actually be doing something useful. Setting it to cool should block off the hot air leakage from that system.

They used an odd little self-adjusting spring clip to couple the bicycle cable to that lever. Is your clip deformed or missing? I've also seen that lever rust up inside the box at its pivots so that it wouldn't move... it's supposed to move pretty freely. If your lever doesn't move freely, that is likely the culprit behind your issues with that cable. Disconnect the cable, then try applying some penetrating oil to the shaft and work it back and forth a bunch of times, while adding more penetrating oil, to see if it will free up. There's only the shaft and the plastic lid - no real bearings. If not able to move freely, it could be the pivot at the bottom of the shaft, which is like a little molded cup in the bottom of the heater box. You'd have to open up the box (-no fun!) and cleanup and burnish the pivot surfaces of the lever shaft. I'd use grease as a lubricant/corrosion preventative. They should have made them from stainless steel...


A fan not working can come from a number of failures; the switches often fail internally. They're still commonly available at auto parts stores. The wiring can also overheat and the slide-on connector terminals can burn up - if you see discoloration of the wire insulation or metal terminal lugs, this has been going on. The terminals inside the big bulkhead connector can also corrode and fail.

When you said it only worked intermittently on high speed, that would be a typical failure of the switch, or possibly of the blower resistor assembly, which is located on the air plenum behind the plastic tray insert in your glovebox. The switches can look OK but be faulty, and the resistors can fail, both electrically and from other issues, such as corrosion due to a leaking windshield frame:

[Linked Image]

Blowers draw quite a lot of current; a minimum of in the 15 ampere range on high speed. They usually fused these with a 20 amp fuse all by itself; nothing else sharing the circuit. Later vans used 30 amp fuses on this circuit.

The blower motors can also fail, as can their bearings, and wiring. Blower motors can still be had in parts stores if necessary, as can the squirrel cage fan. They run on 12 volts; you could jump the battery voltage directly to it temporarily and see if it spins up. The ground wire for them fed through the firewall and bolted on the interior by the engine cover, in front of the passenger seat. In addition to making sure the motor bearings aren't seized up, it might be worth a look to be sure the ground wire is still connected.


A factory service manual (FSM)is a critical piece of life support for these old girls, so please keep looking! You may find one occasionally on eBay, or from other sources. I got a digitized version of mine on compact disk from www.moparmanuals.com - not cheap, but mighty handy and easily tranportable.

I do have a 77 FSM and an 81 FSM, which bridge the two vintages of van Reed and I figure you might have.

Here is the section from the 77 FSM which shows the fuse block, blower switch, resistor, and the blower motor.

[Linked Image]

[Linked Image]


Here is the complete isolated circuit diagram of the heater blower system for a '77.
[Linked Image]

This is the fuseblock description from an 81. I don't seem to have the very same page for the 77.

[Linked Image]

The verbal description of which fuse feeds which circuit was molded onto a plastic cover which snapped over the fuseblock. It typically split apart or got set aside and misplaced...

Good luck!


-It's been such a LONG TIME... BlueShift>> 1981 Dodge Ram B250 Custom Sportsman Maxi Van


[Linked Image]

It's what you learn after you know it all, that counts...

Are you living to work, or working to live?

[Linked Image]

Learning from my own mistakes is good, learning from yours would be much better! [Linked Image]
Re: Need help! 78 Tradesman AC and Heater issues
78dodger #714526 September 23rd 2016 4:31 pm
Joined: Aug 2001
Posts: 12,107
Likes: 37
Maniac
Offline
Maniac
Joined: Aug 2001
Posts: 12,107
Likes: 37
Nice answer Craig!


Windows- they're what make a van worth owning!
Re: Need help! 78 Tradesman AC and Heater issues
78dodger #714686 September 26th 2016 9:32 am
Joined: Sep 2016
Posts: 15
7
stranger
OP Offline
stranger
7
Joined: Sep 2016
Posts: 15
Thank you so much!!!!

Dodger

Re: Need help! 78 Tradesman AC and Heater issues
78dodger #753886 November 06th 2019 3:08 am
Joined: Oct 2019
Posts: 4
Q
stranger
Offline
stranger
Q
Joined: Oct 2019
Posts: 4
Lol I can really relate.... I also have a 1978 tradesman that has a mix of 77 and 78 parts installed :/ production date January 1978... I guess they were just using the left over parts from 77 lol best of luck... Qt Pie and VanNilla 😁🚐👨‍👩‍👧‍👦⛽🏞️🗺️🛣️🐦🐁


find our van on instagram @ VanNilla_78
Re: Need help! 78 Tradesman AC and Heater issues
Ram4ever #753887 November 06th 2019 3:12 am
Joined: Oct 2019
Posts: 4
Q
stranger
Offline
stranger
Q
Joined: Oct 2019
Posts: 4
THANK YOU!!!! Lol you have saved the day with this post :)🚐👨‍👩‍👧‍👦⛽🏞️🗺️🛣️🐦🐁😁😁😁😁😁🙏☕


find our van on instagram @ VanNilla_78

Moderated by  Astro, Ram4ever 

Link Copied to Clipboard
Donate


Upcoming Events
discovery
Who's Online Now
1 members (Wedgy), 20 guests, and 9 robots.
Key: Admin, Global Mod, Mod
Newest Members
TheDrunkenGunsmith, Jac, LOVclassics, ZenMuffin, Milkman530
12724 Registered Users
Top Posters (30 Days)
SDMickey 130
CatFish 28
frscke1 28
Wedgy 21
Forum Statistics
Forums68
Topics35,747
Posts537,897
Members12,724
Most Online177
May 8th, 2013

Powered by UBB.threads™ PHP Forum Software 7.7.4