I have a 97 Dodge Ram 1500 4x4. Just replaced the heater core, thermostat and I still have no heat. Blower motor works well. Once up to temp no heat, I checked the lines going to and from the heater core. Both hot and I just can't seem to figure out what it is. All info is appreciated

 

Air in the heater core.

 

Check the blend door coupling.
https://heatertreater.net/dodge-ram-95-02

 

97 is cable operated. No coupler.

I would verify that the blend door is still intact, and moving properly though.

 

Wasn't sure if it was 97 or 98.

 

I just went thru this yesterday on a '00. In this case it was the t-stat but it was pretty obvious beforehand because the entire cooling system just wasn't developing much heat.

I know OP said he replaced his t-stat but I thought this pic was fun. I've never seen one stuck SOOO open

 

I've also kinda thought Heater Treater's info is a bit misleading. They clearly say '95-02 but aren't ALL Rams cable until '99 or '00? The '98 I service is also cable.

I mean their product is otherwise fine but it doesn't instill confidence in their tech info if basic info like model years is so far off.

Or maybe some Rams got the electronic blend as early as '95????

 

So far as I know, the electronic control for the blend door came in 00. Prior to that, they were all cable operated.

 

Once in awhile my 97 dodge ram 1500 5.9L will drop rpms going from drive to reverse and vise versa. Almost to the point of stalling. When sitting and idling or driving no issues at all. Just occasionally when backing up then going into drive. Any ideas?

 

Electronic Temp Control entered in 1999. That, plus green LCD display, rotary headlight switch, relocated air bag switch and new cubby debuted in 1999.