Hey All, New to the board. About two weeks ago I brought home a new to me 98 Ram 1500 SLT Quad Cab with the 5.2L and the Auto trans. So far I love the truck, but i am having an issue with the heat. And yes I searched, couldn't find anyone with my exact problem.

My heat just flat out blows cold no matter what. Even when the engine temp is up to 180. wih the temp **** all the way to the right (highest heat) and the fan **** only set to its highest setting, I can feel warm air coming from the vents. But when I move the top **** to select a blower setting, it will blow warm air for maybe 5 seconds, then just blow ice cold air. And it does this on every blower setting, even defrost mode.

Now its true it doesn't get that cold here in San Diego, but it does get cold enough that I want some friggin heat when I'm driving home from work at night. So whats everyones suggestion? what might be causing this problem?

 

Welcome!
A couple of things to check.
1. Are you sure the heater hoses are hooked up? Sounds silly but the previous owner may have had it bypassed for some reason.
2. If they are hooked up (and correctly) remove them and flush the heater core out with a garden hose and check flow.
If all is good so far then you probably have a problem with the blend door in the HVAC plenum. It may be disconnected, the motor may be kaput, elec. connections missing/broken somewhere between it and the control head.
Good luck!
WC

 

where exactly is the blend door located? is it easily accessible? should it be opened or closed for the heat to work?

 

Blend door is on the right side of the HVAC plenum (inside).
To access, the dash has to be removed or at least rotated down enough to get the HVAC box out.
Open or closed is relative as the door is a DIVERTER in that it swings between the a/c evap. core chamber and the heater core chamber. You could say it should be "open" for heat which closes the a/c; OR anywhere inbetween for a "blend".