jpaul4

I live in Ohio and it Cold most days here. My heater was working fine and then one day this week it just stopped blowing hot air. I can turn the temperature up to the max but no air is blowing out. It’s a 2015 S550 CPO with 40k m miles. I would think this is covered under CPO warranty.
I appreciate any help getting this fixed.

kikivoinea

Had this issue

It seems that it is a common problem , even in older S class models ( still haven't found a way to fix it )

It is a sort of pump in the front of the windshield. They crack.

It is this one : https://www.ebay.com/itm/Additional-...-/163938306133

Or similar...

Not very expensive , and easy to replace ( 30 minute job )

Good luck

C Swenson

If it is your auxillary pump then here's something to read: https://www.underhoodservice.com/mer...p-diagnostics/
Reading your post I can't determine if you are stating that your heater is not blowing hot air (but fan is working) or that it's not blowing any air at all (fan not working).

jpaul4

I don’t think this is the Auxiliary water pump, as I am not getting any forced air out of the vents.

C Swenson

Fuse?

C Swenson

That should read:
Fuse?

jpaul4

I took it into the shop and they diagnosed the blower motor resistor was bad.It was replaced under CPO coverage, the part was a little over $300. Glad to have it working again.

C Swenson

emilner

I had the same thing on my 2015 S550- either the motor or resistor was bad. They had to take the whole dash off to fix it.

jpaul4

to replace the resistor all they had to do is remove the access panel underneath the glove box. They did not need to remove the entire dash, you can also access the motor fan from this location.

MBNUT1

Thank you for posting the issue and resolution. Beautiful S Class BTW.