heater problem

I have a 1999 Dodge Ram 1500 Quad Cab 318/5.2L V8 Magnum. It has 116k miles and runs near to perfect. The heater, however, does not. If I leave the truck running for a half hour,
then I get some heat, but not a lot. It doesn't heat up any faster if I am driving. What are the most likely culprits, and in what order should I check them? I would prefer to have the cheapest options first. This is kinda important, as I am in Oklahoma and have a 9 month old. Also, links to any helpful diagrams/photos/guides would be greatly appreciated. I have been looking for the FSM but have not been able to find it for this model. I have only had this truck for six months, and as far as I know, all except the tires is stock. Thank you all for your time.
Corby
P.S. Sorry if this double posts...using an unfamiliar newsreader
-------- Binary Usenet downloading made easy =--------- -= Get GrabIt for free from http://www.shemes.com/ =-
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Corby wrote:

Thermostat is stuck open.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Check to se ethat the radiator is completely full. Make sure I have a good thermostat Check the blend doors to make sure they are not stuck closed. Check climate control AC is not running while you ask for heat.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Some Car's/ Trucks have a leaver on the heater that is moved from hot to cold. If your unit has one, Check to make sure that the valve controling the water flow to the heater coil is opening and closing all the way, if not adjust the cable at the valve end to make sure the valve is being opened /closed all the way.
best regards, larry

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Corby wrote:

For my Caravan, it was a 5 minute blend-door fix to solve this.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.