Cold heat
 

Noticed my heat sucks in my truck not very warm at all any ideas

The first and foremost thing that you need to make sure that your truck is getting up to temp (and staying there). I had a bad T-stat in my truck, threw a 190 degree one in, and it made a big difference. I have also heard that the new t-stats for the 6.7L cummins are the same size and open at 200 degrees.

Next thing to check is your fan clutch. My was sticking on, causing it to cool down very fast when not being driven. There should be tests that you can find and do on yours to see if it is stuck engaged or not.

A few tricks that I have picked up on is running a winter front is a great way to get your truck to retain heat and build it up quicker. Personally, I just throw a huge piece of cardboard in between my radiator and intercooler, works great when running around town unloaded (if hauling, I wouldn't do this because of overheating risk).

Next thing to check is your heater core. The easiest way I've found to do this is by getting the truck up to 190 coolant temp, and then taking a infrared temperature gun and checking the intake hose for your heater core (which of course will be at 190) and then turn on floor full blast (floor doesn't use AC to control condensation). You should see a drop of 30 degrees in and out of the heater hoses (160ish outgoing temp). Anything less, you might have a clogged up heater core.

And of course there is always the rout of getting an auxillary heater placed under your seat to blow some more warm air. Also keep in mind these are diesel trucks, they arn't going to warm up as fast as gasser (if you live in a cold climate, look into getting your 3 cyl. High idle enabled)

Best of luck and happy thanksgiving

agreed I use cardboard and keep er plugged in,
the faster the engine gets warm the faster you get heat