Burning smell in cab with hvac off?

[The motor guy]

Definitely doesn't smell the best when you turn the heater on, but it works good. Have only used the heater a couple times since I bought the truck. Smell goes away with the ac on, but whatever the smell is its making me sick. Now if you have the hvac totally off is when it's the most noticeable. Haven't noticed anything leaking, so I don't think it's the heater core.

 

[CharBaby]

Does it smell like it could be a rodent?
Maybe it died in the vents?

 

[Lubener]

If you know a grumpy old man, could be a fish under your seat.

Serously, it could be some oil leaking from a valve cover onto the exhaust manifold and working its way inside the cab..

 

[The motor guy]

Does it smell like it could be a rodent?
Maybe it died in the vents?

I don't think so. It was sitting outside for about 3 weeks in the same spot while I was working on it waiting for parts etc.

 

[ARCOgraphite]

My lease car would get a rodent nest in the turbo heat sheild if it sat for more than a couple days. I actually had a underhood fire heading to Boston one day. Couldn't pull over, luckily it smoked itself out before insulation lit up.

Have a cabin filter? yank it and take a look. I had a rodent nest in an old Mitsu /Dodge coupe that threw the heater blower wheel (squirrel cage) way off balance

 

[dumkid]

Is it a new car? It could be the chemicals getting cooked out of the plastic by the heat from the heater core.

 

[The motor guy]

Is it a new car? It could be the chemicals getting cooked out of the plastic by the heat from the heater core.

Nope my 99 dodge ram

 

[ARCOgraphite]

Nope my 99 dodge ram

What did you repair on the truck?

I just re read this thread, could be PCV issue, Also hidden leak or leftover oil burnoff.
hopefully no wiring issues. Have you lost any fuses?

Another thought, Catcon overheating.

 

[The motor guy]

I had the ecm repaired. I didn't notice the smell yesterday. Now it's only when I turn the heater on. Smells like antifreeze, but I don't notice any leaks or coolant loss

 

[ARCOgraphite]

I had the ecm repaired. I didn't notice the smell yesterday. Now it's only when I turn the heater on. Smells like antifreeze, but I don't notice any leaks or coolant loss

Might be a small weep. A Drip. Hope it's easy to get the box open

 

[The motor guy]

Might be a small weep. A Drip. Hope it's easy to get the box open

Can you get around not removing the dash to access these on a 2nd gen dodge ram?

 

[The motor guy]

I ran around with the heater on a good amount today and the smell has went away. Maybe it just needed to be used? The heater core definitely needs to be flushed though, it's only putting out warm air.