crossy

I have been here a few times and complained of LOW HEAT issues. I thought I pretty much had it narrowed down to a bad control cable or mix door that was not working . I can see that the cable is OK now and I see at least the rod that the door is hooked to working and I can hear the door inside thumping closed/open when I operate it manually . I have the dash 3/4 removed ( can't remove fully w/o disconnecting a LOT more wires because of previous owner add-ons) I do have enough room to get whole heat box out now, It's BEER BREAK time tonight and I got looking and reading some info from a factory shop manual that a Dodge dealer manager was kind enough to reprint for my pop. this heat system blows through the A/C core 100% of the time it just get redirected through a door and the heater core when HEAT rather than A/C is called for . now I realize that the AC core is not supposed to be 'charged' but being there is an electrical switch somewhere that tells it what to do ( maybe more than 1 switch??) who's to say that something is not wrong at that 'signal switch' or whatever it is called and the AC core is not ice cold all the time. that would cool the delivery air down so much the heater core would not be able to overcome it . It's kinda late in the game to unplug the compressor to know , but is this a possibility???<br> I had the truck out this morning before I pulled Dash stuff apart and it actually warmed up here pretty good today. with everything that I had blocked off across the front the ENGINE got much warmer than normal up to 200* or better(normally 170*) that gave me a chance to verify that it is not a Thermostat issue. With the heat on LOW speed and temp cranked up I could feel HOT HOT air at the floor outlets. as soon as I cranked up the blower speed to high it cooled the air right down. The air gets considerably warmer if I had the selector switch on recirc??? <br><br> ?????? ever heard one of these trucks ( Cummins Turbo Diesel) that 'sneezes' real hard at idle? it makes the whole engine skip a beat. <br> thanx , DAVE<br>

Alan_Reagan

The control switch on my truck that controls the &quot;mix&quot; has one position that does not show the AC symbol (snowflake) but the AC is activated when it is in this position. <br><br>Also, it could be that the relay is stuck &quot;on&quot;. Try removing the AC relay if you think this is your problem.<br><br>

crossy

&quot;Also, it could be that the relay is stuck &quot;on&quot;. Try removing the AC relay if you think this is your problem.&quot; <br><br> That was kinda my point, problem is I found 3 or 4 inline switches. I don't know squat about AC system operation. DAVE<br>

Redleg

GM has a position (can't remember which right now) that would give you your heat as selected, but the AC compressor would still kick on occasionally. This is suppose to keep the components lubed and in good order through the winter months. Not mine, but a friend had AC problems we believed to be contributed too by this control. Could Dodge have something similar that is causing your problems?

danlit

Sounds to me like your heater core has a flow problem.<br> Danny

crossy

nope already discussed before . temp within 10* in/out. DAVE

REDLEG . your talking about the defrost mode. it does that to help Defog your windows. Yes , this truck does that.

crossy

just removed the box and found nothing wrong with anything . I think my theory of the AC core being charged all the time may have been right . heck of a lot of work to find NOTHING!. <br>lord this is a wimpy a$$ heater core for a big truck .DAVE

Alan_Reagan

Crossy, My point was, remove the relay that controls the compressor. No matter how many switches you have, without that relay, the compressor won't turn on with the relay out. Or better yet, with the heater on, raise the hood and see if the compressor is coming on.<br><br>What I said about the switch having a &quot;compressor on&quot; position is the first hi/lo vent position going clockwise. There is no &quot;snowflake&quot; on that positon but the compressor will operate there.<br><br>Crossy, Go the the first hi vent position with no snowflake and see if the compressor is coming on. The system is always charged unless you have a leak, but will not cool unless the compressor is operating.

crossy

NOPE , NOPE &amp; NOPE nothing worked :'(. 2 days of back pain,sore knees and busted knuckles later , no charge in AC at all and still no decent heat. It just warmed at least my heart though to tell my wife I'm selling it. thanx for the help, DAVE.