2nd Gen Dodge Ram Heater Box Diagnostics and Common Problems

In this video I break down the functions of the heater box in the 1994 to 2001 Dodge Ram pickups, as well as going over common problems that can happen and how to diagnose and fix them!
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[@michaelbuettner6560]

One of the best videos of both the heater core which needs replaced and the evaporator, hadn't seen much that was clear... a big thanks!

[@Hazardous-Hotrod-Knowledge]

Thanks! Glad the video was helpful!!

[@DavidBoatwright-e7s]

You are the Man...Really want to thank you from the bottom of my Heart❤

[@notdavid8175]

this is one of, if not the best video on both the heat core and Evap on the ol YT. Good job Sir.

[@fonzysgarage1534]

Great looking 2nd gens! Both are perfect in their own way!

[@bildough2775]

The maroon truck and black truck are lookin great!

[@philhargrave5529]

Sweet looking trucks mate. I have a 96 CTD with a NV4500 that I use for work. Im in Australia so it was converted to right hand drive back when it was brand-new. She's a very rare beast over here.

[@Hazardous-Hotrod-Knowledge]

I’ve seen a couple pictures of those weird RHD second gens, very well done and weird to see!

[@bigindian1987]

Wow a video with all the information I was looking for

[@Hazardous-Hotrod-Knowledge]

Glad it was helpful! Thats the goal haha!

[@woodrownelson2711]

They hand make them in California called brass Works

[@derekcoiner5946]

South Main Auto has a great video on doing a heater core flush with CLR. it works great. my 94 ram 2500 gasser had tons of flow through the core but the air came out colddd, flushed it in both directions for about 30-40min, hot heat now and has stayed that way.

[@GRasimos]

Thanks for breaking this one down bro.

[@Hazardous-Hotrod-Knowledge]

Glad it was helpful for ya!

[@bsrob1]

Thank you! This is so helpful! My a/c blows on floor and vents. I think my floor door is messed up

[@jackclark1521]

Man that helped me so much you have no idea!! Thanks buddy 😂

[@Hazardous-Hotrod-Knowledge]

Glad to hear it helped you out!

[@Beast_is_a_dumbass220]

Great video! You were driving me nuts calling it the A/C condenser; it’s the evaporator 🤪

[@Hazardous-Hotrod-Knowledge]

I always get them mixed up hahaha!

[@TedOption]

Good video. Thanks.

[@bobmartinez3038]

thank you for this video,it was very informative...

[@johnyhefner]

Thanks! Amazing video.

[@Hazardous-Hotrod-Knowledge]

Glad you liked it! Thanks for the comment! :)

[@scottammon8395]

Thanks for a very good video.

[@thesheamiester3849]

My 99 has the electric blend door, I got a heater treater.

[@GeneNagel1968]

Thank you for this video it's going to help alot when I get ready to do my heater core. My problem right now is I replaced my fan and now I have no air movement out any vent at all. I've pulled the fan.. it's working but no air comes out anywhere. Any ideas😳

[@Hazardous-Hotrod-Knowledge]

How strange… is it possible the fan pulley is “slipping” on the fan motor shaft? So free spinning in your hand it’s fine but when it’s under load/moving air it spins?? Not even on defrost at the top vents it does anything?

[@juliedalton482]

Fantastic - Many Thanks!!

[@Hazardous-Hotrod-Knowledge]

Glad it was helpful!!

[@tannerkawi]

Great video! I have been trying to troubleshoot a problem where my 01 on max ac or just top vent always will blow air to the feet vents also. I’m sure it’s a problem with the door like you showed but is there any way to fix that without removing the hvac box?

[@supafly136]

superb!

[@MrSlipknot1969]

Thanks for sharing!

[@Hazardous-Hotrod-Knowledge]

Happy to see so many people finding the video helpful!=

[@chuckluck3303]

Great video thank you.

[@Hazardous-Hotrod-Knowledge]

Glad you liked it!

[@alexanderanduze4680]

Where can I buy new linkages for the heads and hands door running to the vacuum diaphragm? I haven’t been able to find it anywhere online and I could probably use a new door as well. I also need a new foot diaphragm. Rebuilding the entire box. Last place is the junkyard. Any links would be appreciated.

[@Hazardous-Hotrod-Knowledge]

I havent heard of anything like that, honestly if its not on rockauto then I dont know of anywhere else except for a junkyard

[@fasterthanaturtle]

Great great video thank you. How many hours was the whole job? Was that your first time? I got to get in mine and I'm a little scared

[@Hazardous-Hotrod-Knowledge]

I’ve done it all a couple times, I’d say 2-3 hours for myself all in, but for a first time you may be looking at 4-5 hours tops

[@JerryMiah]

May be a long shot here, but is this similar on a 99 dodge ram 1500 VAN? I cant find ANYTHING ANYWHERE on the ram van hvac stuff. I've figured out most of the stuff I need to just from trial and error. Kind of rednecking it to make it work so we don't have to spend over 1k on someone to tear the whole dash out and fix little things, but one last thing I'd like to find is the recirc door. when i switch from a/c to max a/c there is no different in the sound the blower makes, so Im assuming the door is stuck or the actuator is non functioning. Any help or maybe a video on one would be awesome! Thanks! Great videos btw anyhow. You did a great job explaining the functions on a truck HVAC.

[@Hazardous-Hotrod-Knowledge]

Oh man I’ve never messed with the old dodge vans, I imagine they’re probably totally a different design but also very similar in how it functions…. You could remove the blower motor and then select AC max and see if you can feel the recirc door close as it should be somewhere near the cavity of the blower fan? Then if it doesn’t work that just means a vacuum leak or bad vacuum pod

[@JerryMiah]

@@Hazardous-Hotrod-Knowledge ok thanks!

[@JC-vy1bo]

Great video. I have an odd problem that i can't find a fix for. I have an 09 Ram. The ac works well, but when I turn it to hot it blows heat very well (good temperature), but it only blows at about 30 to 40 percent of the force that the ac does. Recirculation doesnt make a difference. I can't wrap my head around what this could be.

[@Hazardous-Hotrod-Knowledge]

Maybe it has something to do with the way the vents/flaps are routed? Like heat + AC it has to now pass through 2 radiators instead of just 1 for the heat? But that’s how a 2nd Gen is done and they blow good

[@honey8784]

Good video

[@Hazardous-Hotrod-Knowledge]

Thanks for watching! Glad you enjoyed it

[@harleydecker9148]

Best video of the break down of the box. Thank you. This is my favorite dash rip out video: kzbin.info/www/bejne/a6rYlYmsqKl1fLc With both of these tutorials, it's time to replace my dash pan, heater core, and evaporator. Thanks again for this kick ass content.

[@MattSkruff]

i replaced my heater core. HEAT! first time ever! shut truck off. never had heat again since that day. any thoughts?

[@Hazardous-Hotrod-Knowledge]

How strange… low on coolant? Got air in it? Does it have the electric blend door?

[@Ibelieve218]

there's only 1 vacuum line to the box right?

[@Hazardous-Hotrod-Knowledge]

yup, it comes through the firewall, a single plastic line that is routed alongside the grommet for the AC lines.

[@jamesvelasquez4236]

What my brother is goin thru, i would like to flush the core but i think its that blend door actuator, he barely get heat when he flips it to heat, like luke warm usually entails blend door, got heat to bith side of the heater hose so i know it aint plugged

[@Hazardous-Hotrod-Knowledge]

Pull off that actuator piece and see if the interpolator(?) coupler thingy is broken

[@Man.who.sold.theworld]

I have 1999 dodge 2500 for about 3 months Ac Worked then stopped, winter came around so I just swept that under the rug and when I went to use heater I noticed my heater core lines under the hood on the fire wall were chopped any advice would be helpful

[@Hazardous-Hotrod-Knowledge]

oh man, like someone just cut the heater core lines and theres nothing going to them? Sounds like you'll have to get a new heater core and reconnect them. unless the hoses are still there, then it should be as easy and just hooking them up!

[@98dodge360v8]

Is there a way to get to the recirc door actuator without pulling the box? I want to limit the travel on mine. I have a new core, blend door works good. Even installed a heater coolant assist pump for like a RV. Still cold. It gets warm after 40mins but at -20 all it can muster is barely luke warm. Cant keep the windows clear beliw 0F. Thermostat is good.

[@Hazardous-Hotrod-Knowledge]

I was able to zip tie the recirc door shut by just removing the glove box and it was right there. You could possible ziptie it half shut?

[@Man.who.sold.theworld]

If my truck was bypassed am I able to just re connect it?

[@Hazardous-Hotrod-Knowledge]

Yup! I think you can even hook it up backwards so it flushes itself out

[@mulletsquirrel]

My AC doesn't work on my 99 and the heat barely works. I'm not super excited to get in there and mess with it, but with winters getting below zero I'm sure it's not going to be fun freezing. I don't think my shattered dash will like coming out...

[@Hazardous-Hotrod-Knowledge]

This is a late reply but did you ever yank it apart and get it fixed? Hopefully your dash stayed together!

[@mulletsquirrel]

@@Hazardous-Hotrod-Knowledge nope I just left it

[@gardenman3]

could we have a video an how to take the heater box out.

[@Hazardous-Hotrod-Knowledge]

I could make one yeah, I figure there’s enough other people who make the videos on how to do it but I could give it a try next time I have to do one!

[@chasesshop2991]

So there’s no valves on the coolant side, if I’m not getting flow through the box it’s plugged?

[@Hazardous-Hotrod-Knowledge]

Nope, no valves, no flow means it’s plugged good!

[@michaelwhetzel6664]

What if I don’t get a lot of air out of defroster

[@Hazardous-Hotrod-Knowledge]

Pull your fan and see if your AC evaporator is clogged with leaves n such, that would prevent good airflow through it

[@bgy1591]

Do you know why when I hit my brakes I hear a pop and the ac turns off and hot air blows out?

[@Hazardous-Hotrod-Knowledge]

If you have a older truck (1996 and older I think?) or a gasser then you’ll have vacuum assist brakes, what I would think is happening is when the brakes are pressed you have the vacuum drop and that causes the heater box to turn off recirculate (which is vacuum operated)

[@JamesRivera-321]

how many hours did tht take you

[@Hazardous-Hotrod-Knowledge]

Probably 4 hours R&R but I’ve done it a whole bunch, maybe 5-6 for a first timer

[@santiagopatino3954]

thank you for the informative video. Had my jew slave help with faulty actuators.

[@witcher71]

Steel or fiberglass cowl induction hood on the dually?

[@Hazardous-Hotrod-Knowledge]

It’s a steel hood!

[@MattSkruff]

where did you buy it? @@Hazardous-Hotrod-Knowledge

[@mr.anonymous41]

Great video. I own a 2001 Ram 1500 Offroad, best vehicle I've ever had. My heat and ac work but sometimes when I go uphills air flow stops like an internal door closed. Any ideas what may cause this?

[@Hazardous-Hotrod-Knowledge]

Low on coolant? Maybe at a incline it gets air locked somehow, I haven’t looked at the magnum engines too much Or for air flow stopping it’s not actually moving any air… that could be a vacuum leak somehow which would make your vents go to defrost?

[@mr.anonymous41]

@Hazardous-Hotrod-Knowledge thanks. I actually just put a set of new Promaxx cylinder heads on it. They work great BTW, new casting no weak points. It still does it. I have no coolant leaks now. I'm going on a trip soon so I can monitor it some more. If all else fails I'm re-doing the whole interior so I'll pull the box and rebuild it then. Thanks for the reply.

[@mr.anonymous41]

@Hazardous-Hotrod-Knowledge it's definitely has to do with the box. Fan still spinning but no vent air movement. I'll check the defrost when it does it. Thanks again

[@Beast_is_a_dumbass220]

Know anything about flipping the rear axle on these? I have an 04 Dakota and want to lower it as easy as possible; can I just move the springs?

[@Hazardous-Hotrod-Knowledge]

Supposedly the dakotas have the same rear leaf spring spacing as a second gen so you can use 2G rear axles lol Frankensteining fun fact! As far as a axle flip, I imagine it just involves welding on a different axle perch and getting new u bolts made? Then maybe doing a c notch? I have a local buddy with a slammed 93-96 sorta area Dakota