I've got a 1999 Dodge Ram with the 5.9. The heater is only blowing cold air. No heater at all. Does anyone have a clue???

 

It could be overheating, could be the heater core, could be the climate control unit is going bad... Could be a stuck thermostat...

JimK

 

I'd say check your heater core and t-stat.

 

today I took off the cup holder assembly in hopes of gaining more access to the blower motor. Unfortunately, I'll need to remove more stuff. Anyhow, As I was driving I heard this weird noise coming from the heater box. I swear, it almost sounded as if a mouse trapped in there. But it does sound like something inside of it is faulty. Any clues???

 

Are you feeling hot coolant in the line to the Radiator (top big hose, after it heats up)? If that hose isn't hot, blame the T-Stat.

If the blend door is jammed or the actuator has broken you won't be able to switch to the heat setting. You'l probably need ot pull the dash to get to all of it.

You can try to back flush the heater core with a prestone flush kit if you feel the core might be clogged.

 

Yeah, the upper radiator hose does heat up. yeah, it really sounds like something is jammed. thanks

 

The heat in my '99 is not awesome either. I know the blend door is working fine-- the servo buzzes and I can hear the blend door bottom out on each end. I had my core flushed and it made no difference, and the guys at the shop said that only a tiny amount of $hit came out. I suppose it could be partially plugged, IDK.

Did yours just suddenly stop working or did it gradually get worse? If it was sudden then I'd suspect HVAC control issues... if gradual, then the heater core plugging up. FYI the blower motor is on the bottom of the dash under the glovebox. It's easy to take out-- 3 phillips screws. I had a bit of trouble getting the back screw out, but I have big hands. Mine was squealing so I took it out and oiled the bearings with Rem-Oil to try to keep it alive for a bit longer. It seems to have helped.

Anyway, I hope some of this helps.

 

If it's making noise take the motor out as stated above. And btw, the heater core can seem like it has good flow when flushed and some garbage can come out. But, the white, lime like deposits that are stuck to the inside of the tubes will not come out, which will partially block the flow and not give you the expected heat. Since you have no heat and noise, maybe the fan is damaged or disconnected from the blower motor.

 

It sort of gradually but it was also suddenly.
Thank you. I greatly appreciate your thoughts in and advice. I will look into it. sometime soon.

 

Well actually, the fan does blow. And it blow accordingly to the speeds as I turn the ***. At this point I have a strong feeling that it may be the blend door or the heater core. I just I'll just have to look into it. Thanks for your input. I'll get out there some time when the temperature rises a little. thanks again.