No Heat - Can't find Blend Door Actuator!
 

Hey guys, have the typical no heat issue. Radiator professionally flushed, heater core only two years old, and I cleaned all debris out of blower motor. I want to check the blend door actuator motor, see if I need to apply the "Heater Treater" fix, but I can't find it. Everyone says it is suppose to be on bottom of HVAC housing, but do not see it. Just has a smooth lower bottom section, does this have to be removed to get to it? Is it possible that Dodge relocated the actuator motor at mid year production? I have a 98 Dodge Ram 3500 Dually with the 5.9 Cummins 12V.


Assistance is appreciated...driving me crazy! [duhhh]

All the second gen trucks that use an electric blend door 1996-2002 have the motor in the same place, it's down low on the passenger side right next to the hump. Some trucks have a plastic cover over the underside of the dash depending on trim level and if it's still there. It CAN be removed and installed without doing anything to the HVAC plenum.

Thanks for the reply, Will check on this. I noticed that my temp dial is connected to a manual cable which is connected to a white lever on top of the HVAC plenum. Is thts connected to the blend door as a manual cable linkage versus the electric actuator?


Thanks again for the reply!

The manual "boden" cable was used before the electric blend door but I thought that the 1/2 ton changed in 1995 and the 2500 and 3500 in 1996. I might have the years wrong but perhaps someone retro fitted the older style knobs and manual blend door. Perhaps someone with that year of truck could enlighten us.[laugh] If you do have the manual boden cable blend door the cables were prone to either slipping the adjust point or after time the plastic becomes brittle and the attachment point breaks off all together. If the door is moving at all then it's just out of adjustment.If it's broken off I have repaired them before using just a small "P" clip around the outer cable and a screw, just be careful drilling or screwing into the plenum.

Good points. No it is all original, I will work on it this weekend...thanks!

My 96 is cable operated. I thought they all were until like 2000 or newer. Hard to remember though.

Thinking about it I'll bet the heater treater site will give the years that were applicable for the electric blend door fix.

My 98 has cable actuated blend door.

I wonder if the change was 1998.5, the Heater treater site says 95-02 which is not correct.

Yeah, lot of confusion on this! My truck is a 98 12V.

IN FACT, as much as I love this truck, probably going to be putting it up for sale in the next week. Runs great, did a lot of work on drivetrain. Got a son going to medical school, got to tighten up on the "old purse-strings", need to cut back on my vehicles and money!

I am at a lost as too what to do with the HVAC on this truck. All components in cooling system, i.e., water pump, heater core, blower, thermostat, radiator are good. Engine temp is good, sits around 160 degrees when warm, but no heat. My truck definitely has the old-style manual cable to the blend door, no actuator motor. I tried drilling and inserting pin in blend door lever, but no good. Question about two things:


(1) Noticed that the blend door lever on top of HVAC is also connect two and controls movement of another lever, behind the blend door lever. Any idea what that is for?
(2) My problem with heat started couple of years ago, this is when I replaced the heater core with a new one from AutoZone. I noticed that the blend door linkage lever hits the edge of the hole where the heater core sites, is this as far as it is suppose to travel?


Thanks for your assistance guys. This is a great truck, this is only issue I am trying to resolve. I even thought about going to a electric automotive heater, but they seem very limited far as heat capabilities.


Any suggestions are welcomed! Thanks!

Change your thermostat, 160 is nowhere near hot enough should be 190/195. Some vehicles with boden cables have a "turnbuckle" in the outer cable to adjust the cable length so you can adjust the amount of door travel, I don't know if yours does.

Good info, Busboy. My cable does have that turnbuckle on cable, adjusted it, no difference. I am still thinking that the blend door is possibly broke. Sometimes, I get some heat, then next time I start the truck, no heat. Sometimes, I move the tem knob full cycle from cold to hot, then get heat, sometimes not. Its like the blend door is just kind of flapping around, no controlling it. Will keep working on it. As for temp, my truck never has gotten above around 160-170, and I use to get heat. I do have a Cummins 190 thermostat, may try it as well.

If you have intermittent heat then I suspect that the heater core has air in it from the cooling system not being totally full, that could also be why the temp indication is not hot enough.