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Getting heat on only passenger side

58K views 26 replies 15 participants last post by  dz1976biker 
#1 ·
Turned my heat on the morning in my and there is hot air coming from only the passenger side vents (dash and floor). The vents on the driver side are blowing much cooler air. Also the defrost vents seemed to be blowing cooler air. My guess is that it's some valve or door behind the dash and not the heater core or thermostat since I am getting some hot air. Can anyone help me with this one?
 
G
#2 ·
Welcome to the forum.

What year/model is your truck? I suggest you re-visit your User CP and edit your details to add that info. It will help us help you.

I suspect the diverter valve in the HVAC module is stuck. Configurations of this system are a bit different from generation to generation of Ram so that's why it's important we know what year you have.

Attached is a set of instructions on how to get to that system from the FSM for the 2nd generation Ram.

In a moment I'll post up an exploded view drawing that may also be helpful.
 

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#7 · (Edited)
Similar problem on 2005 Dodge Ram 1500




I had a similar problem on my 05' Ram, I can only get heat in the dash and upper window vents, none on the floor. I think its one of the air blend actuators on the vent system, there are three on the vent housing under the dash. I hope yours is fixed. See attached pics..(replacing the heater core is another story!) By the way, all the actuators have the same part number.
 

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#8 ·
I have an 02 ram 1500, and i have the same problems. Heat on passenger side and blows cold on driver side. please help!! when i switch temp from cold to hot i get a short burst of warm air out of the driver side for aprox 5 seconds then back to cold. any suggestions?
 
#13 ·
Hey all. Had the same problem as all of you since last winter. Heat on passenger side and cold on driver side. Was getting the 5 second burst of hot air on driver side when I turned it on. Took apart the dash and I checked all of the motors to see if they were working. The hot/cold air motor is actually inside the HVAC system so we stuck a camera down it to see that it was working. Finally, I just decided it had to be heater core. Took it apart today and the heater core was full of rust!! I was scared to replace the heater core because everyone said it was such a hard job. I did it myself and had everything put back together in less than 4 hours! If anyone needs some help let me know. An $80 heater core plus your own labor is a lot better than an $80 heater core plus a mechanics $900 labor(what I was quoted at anyway)
 
#15 ·
I just fixed this issue on my 02. It was a plugged up heater core. I blew a rad hose a few months back and overheated so it must have set loose a bunch of rust flakes. I removed the hoses and back flushed it numerous times in each direction. I ran the discharge into a bucket and was shocked how much came out. The good news is, I had tons of heat everyday since.

I still have another issue where I don't get air flow to the floor on either side when in recirc to floor and dash. It works in other modes so I believe the blend doors are al functioning. My next step is to pull the controller apart and check for broken solder joints on the controller. Need to pul my Master door/window switch and do the same to it as well. It's always something but thankfully it never adds up to the cost of a new truck.
 
#17 ·
I would start by flushing the heater core first and then look to the blend doors.

I have owned numerous Dodges over the years and have had to flush the heater core on a couple of them. My 95 2500 V10 was the most notable since it had zero heat anywhere, (not fun at -45F). I flushed it in under 45 minutes and went from no heat to all the heat the V10 could put out. When I mentioned it at work the next day, I discovered 4 more guys with dodges that had the same problem. We all got together at my shop and flushed everyone of them and they all recovered 100%.

The Dodge's must have extra small ports that are easily blocked since all I have ever recovered was mostly rust flakes and the odd bit of silcone from original engine assembly.
 
#19 ·
Same problem, no heat on driver side

My 2005 Dodge Ram 1500 has the same issue. While the air coming out the passenger side is nice and hot on all levels, on the driver side it comes out cold whether at the feet, the face - the Heater treater videos look like a lot of work for not being sure which door is broken . I have the dual controls so that the passenger and driver can adjust climate separately. Can you tell me which blend door/s I should be replacing based on my symptoms? I don't seem to have any issue with switching from different levels so I assume it's not the mode doors.
 
#22 ·
You need to flush the heater core itself. It's a mini core similar to the rad only mounted inside the heater unit under the dash. There are two hoses that run up the passenger side of the engine from the water pump area up the the heater core inlet and outlets protruding from the firewall. Disconnect both these lines and alternate running water thru each of them.

Sometimes the two lines running to/from the heater core have a plastic joint with a couple hose clamps so they are easier to pull apart and flush.

I usually run one line into a bucket and then attach a hose to the other so I can flush and catch and see what comes out of the core. Usually it's a lot of flake with a couple chunks of silicone gasket clumps.
 
#24 ·
cold driver + warm passenger = heater core (for my truck)

I just replaced the heater core in my 2002 1500 quad cab (dual zone control). I had the same problems, no heat on drivers side, warm on pass. side. My core ended up corroding and leaking out of the back side. As it turns out, the rear of the heater core was plugged and that's the side of the core that heats the driver because the dual zone system uses two independent blend doors that are split with one set above and another set below the heater core inside the HVAC box.

I suppose flushing the core might be something to try, but I knew mine had been leaking for a while. The antifreeze even soaked and degraded the foam on some of the blend and mode doors bad enough that I had to replace it with some weatherstripping from the hardware store.

Sounds like some guys are having troubles with broken blend doors and such and many of them recommend the heater treater, but everything on mine looked good, besides the core and some rotten foam.

I decided to put in a new A/C evaporator too, since it was all in there together.

I'm really glad I did it on my own. Learned a lot through the process and saved a ton of $$. :smileup:

Hope this helps anyone out there with similar problems. GOOD LUCK!!
 
#25 ·
Wow seem like everyones having the same problem of having no heat on the driver side and only some heat on the passenger side. Well check this out. I've got NO heat on my passenger side and very little heat on the drivers side? And that very little heat only works on the lowest control settings. If i turn the heater up it only ends up blowing cold air. I'll turn it off, wait a few seconds and turn it on and it'll be warm again for only a few second. Again only on the drivers side. Mines a 2002 Ram 1500 4.7. I bought it a year ago with 94000 on it. Since i"ve had it I put a new motor (the old one ended up with probs cause some ******* decided to put a shitty weld in the radiator, but thats another story), and replaced the rad, thermostat, waterpump, and the place i bought it from put a new heater core in it. I did't replace any of these parts myself so I don't know the quality of how they were installed. Sounds like my problems are the same as everyone elses accept I have no heat on the passenger side and minimal heat on the drivers side. Where shall i start to fix this? Anyone have a course of action on where to start and to move on from there?
 
#26 ·
In your case I would start by verifying that all your blend doors are connected and working properly.

It probably wouldn't hurt to backflush the heater core as well. It's not clear if the heater core was replaced before you bought the truck or after the engine was replaced but either way, it has small ports and is easily plugged by any debris in the system.

Overheating an engine loosens a ton of flake and debris from inside the block and would definitely cause this issue.
 
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