Moist Air only

2000 Dodge Ram 1500 Pickup 2WD 113,000 miles
Since about two (2) days I have completely fogged windows while driving, making it really difficult to see and almost dangerous to
drive. I could not figure out what it is, playing with the temperature dial on hot and cold as well as directing the airflow to window or not. What I am also noticing is that it seems like I have mist coming out of my air vents. I now believe that the system pushes moist air into my cabin and I am suspecting a pin hole leak in my heater core under the dash where coolant escapes and makes the air moist only. I have not noticed any noticeable loss of coolant, however I believe it is going down.
Anybody had something similar happening? Am I right to assume that I will have to pull the dash out in order to change the heater core? Also, when I operate the temperature dial, I am actually changing only how much air runs over the heater coils and not how much coolant flows through them, correct? I am thinking also to just proof my theory, that I could clamp the hose going into the heater shut right before the firewall to see if it changes anything. Should I be ok to do that? As far as I know the system does not rely on that flow through the heater to keep circulating.
Any advice is greatly appreciated.
Thanks in advance. Axel
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I suspect your air conditioning isn't running when you put it on defrost. It comes on to remove the moisture in the defrost mode. Start your engine and put it on defrost with the temperature selector on heat and fan switch on full. Open your hood to see if the clutch on your compressor is turning. If not, the a/c compressor is not coming on (low refrigerant, etc).
If it's coolant, you'll definitely be able to smell the antifreeze.
Dave Young
axel wrote:

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A leaking heater core will usually result in coolant dripping from the floor vents.

Yes
Correct - there's no control over the flow of coolant through the heater core. It flows all the time.

Yes, you could do that. Coolant flow through the heater core is in parallel with coolant flow through the engine. Just be sure you get the right hose - clamping off the return won't help matters any.
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A leaking heater core will usually result in coolant dripping from the floor vents: Yep, I can see the coolant on the floor vent - so the good news is I know that I have a leaking heater core. I plan on disconnecting the two (2) hoses going into it and just connect them so that it bypasses the heater. With that I can at least tackle this project on my own schedule at a convenient time.
Question: In order for me to replace the heater core, I will have to remove the dash board. Correct? My dash has been out twice before: once to replace the AC unit sitting under it right behind the passengers glove compartment, the second time the dash was pulled out and a new one put in because of the cracking dash board - I did not have to pay for that. However, it is a big bill to have it done, so I wonder if I could do it myself over a weekend. Anybody out there who has tackled this job himself before? Any special tools, thoughts, helpers needed?
Thanks. Axel
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That's exactly what I did with mine.

Correct.
Yep - I did it once myself - paid someone else to do it the second time :)
There's no special tools needed, beyond the tools to recover the A/C system and disconnect the fittings (suggest you have a local A/C shop do at least that much for you). There's a lot of little details, but they'll be apparent as you go through it. Essentially, remove the knee blocker panel, remove the bracing of the lower dash so that the dash can come up over the steering column. Unbolt the steering column from the mount (two nuts), and set it on the seat. Remove the five or so screws on the top of the dash, close to the windshield. Remove the A-pillar trim pieces, and the lower side kick panels. Behind those kick panels, loosen, but do not remove, the but bolt that acts as a pivot point for the dash frame. Disconnect all the connectors at the lower-left firewall (cab side), including the big one that's bolted together - loosen the bolt to disconnect it. Remove the heater controls, and disconnect the vacuum harness.
Now, pivot the dash down, lift it off the pivot bolts, and set it on the seats. From the passenger side, disconnect any other wiring (things like the antenna, which has a disconnect point on the passenger-side kick panel - the connections to the HVAC box - anything else). If you have enough room to swing the passenger side of the dash back and get to the HVAC box, then fine - otherwise, with a helper, remove the dash panel. In a pinch, you can bolt the steering column back up, and drive the truck (I did just this on my '95 - drove it to the guy who was going to replace the A/C evaporator).
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Do you have to do anything special to prevent the air-bag from going off?
--
Ken



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YES!! The very first thing you do is disconnect the battery and wait ten minutes before proceeding.
Mike

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wrote:

I bring home flowers once in a while!
beekeep
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Went ahead last night and pulled both hoses off the heater and connected them to each other. 2 more questions regarding taking the dash out: A) My repair book talks about the vacuum operated control assembly of the heater unit. Will I have to discoonect this along the way and then have to apply a vaccum again, or woould I only have to apply a vaccum manually in case I take that even further apart? In case I need to, any advice in regards to getting a hand vaccum pump. B) The instrument cluster bezel has to come off. When the 1st shop had to pull the dashboard out, they managed to leave it intact. When the dealer replaced the dash, they broke the bezel - slight but visible crack on the top in the middle off the intrument panel. I am somewhat afraid to pull this bezel out and break it in the process. it took the dealer about 6 month to get one as it was a national backorder due to the demand that replacing all the cracking dashboards generated. I didn't really care as they replaced it for free, but now I would have to pull it out myself and of course, if I break it I would need to get a new one. Any advice on how to get it out without breaking it? Can't be that hard, anybody who puts is custom radio in would have to do it.
Thanks in advance for all the valuable tips. I think I made up my mind and will attempt this project over a long weekend or so, as I think as long as I plan on having the truck I will have to do it again most likely to replace the AC unit under the dash, so I might as well figure out how to get the dash in and out now.
Axel
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No - vacuum comes from the engine when it's running. You only have to disconnect it becasue the vacuum lines will remain behind, while the heater control has to come out.

It's all just held in with spring clips. Best advice is to start in the lower-right corner, using a trim stick, and just carefully pry the bezel off from the dash. Slide the trim stick along the outer perimeter of the bezel, locating each spring clip. Prying right at, or immediately alongside, each spring clip will minimize the amount of leverage you're putting on the bezel. I had the one on my '99 off and on many times, and it was never a problem. It sounds like the dealer tech was a bit too "aggressive".

If it's the original A/C evaporator, I'd go ahead and replace it while you have everything apart. The factory units have a HORRIBLE reputation for leaking. Each of my three trucks has had the evaporator go on them - one of the major factors why I purchased a service contract on my '03 (almost paid for itself on that one job alone).
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Might be a stupid question: What does a trim stick look like?
Axel
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wrote:

Might be a stupid question: What does a trim stick look like?
Axel
It is a thin, stiff plastic stick that is slightly curved to help remove trim parts. In a pinch, if you are careful you can use a stiff putty knife that you have wrapped in masking tape. The tape keeps the metal from scratching the trim. Just don't be too aggressive.
I agree with Tom, if there is any doubt or if you have a lot of miles on the truck or if you see any stains at all on the evaporator core, NOW is the time to replace it.
Mike
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I had the a/c evaporator replaced about 2 1/2 years ago and the a/c has since run fine. So, I should be good with that one for another few years I hope. I actually found a picture of a trim stick after searching for it on the net and yes a putty knife wrapped in masking tape should do the trick. Once I attempt the project I will let you know how it went. One hint the shop guy that I asked for a quote for the entire job gave me was that they ran into the issue of not fitting heater cores with after market suppliers and had more than one case on Dodge's where they had to actually had to go to the dealer to get the heater core that fits. Any thoughts on that comment?
Axel
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wrote:

I had the a/c evaporator replaced about 2 1/2 years ago and the a/c has since run fine. So, I should be good with that one for another few years I hope. I actually found a picture of a trim stick after searching for it on the net and yes a putty knife wrapped in masking tape should do the trick. Once I attempt the project I will let you know how it went. One hint the shop guy that I asked for a quote for the entire job gave me was that they ran into the issue of not fitting heater cores with after market suppliers and had more than one case on Dodge's where they had to actually had to go to the dealer to get the heater core that fits. Any thoughts on that comment?
Axel
In the parts biz, you get what you pay for. I have seen many times that low-cost, aftermarket parts just don't fit/perform well. I would try to avoid any parts from AutoZone as they sell strictly on price and much of their stuff comes from China and is of dubious quality. The best fitting (and most costly) part will come from the dealer. Get the dealer price and use it as a baseline. I would try to find a NAPA parts store and use it as the source as NAPA still sells quality parts. An aftermarket brand to look for that is of high quality is Modine.
Hope this helps!
Mike
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Tom Lawrence wrote:

I broke the bezel on my '99 a couple of months ago in the same place while putting a molded dashtop cover on. I've had it off many times before also. I think they get brittle with age.
--
Ken



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axel wrote:

Coolant has a very distinctive odor. Heat some up and you'll see what I mean. If you have a leaky heater core, you'll know it right away.
The defroster is supposed to run the A/C at the same time as the heater. The A/C core catches the moisture out of the air. Make sure that's working correctly.
All that trapped mopisture has to go somewhere. There's a drain out the bottom of the box, to the outside of the truck. Make sure that's not blocked. If it is, the box will fill up with water.
--
.boB
2006 FXDI hot rod
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