fergdaddy

I have a 2013 GLK350, I have AC but no heat, the shop said it was the water pump but the engine is running fine and not over heating so I don't think thats correct.
Looking on line it looks like the 2013 GLKs no longer have a "heater control valve" (they stopped in 2012 and replaced with an aux heater core) which I thought it could be, any thoughts.
I was thinking it was the heater or Aux heater core.
I was thinking about flushing the coolant but it's in the low 30's now but it's still an option is that might be it, a clogged or obstructed core.

formerjeepguy

You have the two water pumps. The primary pump is belt driven on the engine and the auxiliary is electric. Perhaps the electric pump died and is blocking flow to the heater core- rockauto has them for $45-ish. However I have no idea how hard it is to replace.

Was this a shop that specializes in Mercedes? If not then take it to a Mercedes shop.

fergdaddy

The pump is sitting right next to the coolant recovery tank and was easy to get to and replace, however that appears not to be the issue. There is no 12VDC going to the pump and the old pump (I bench tested it) seems to run fine, So I am wondering if it is the ambient air temp sensor, bower motor control module (not switching from AC to heat sending 12VDC to the pump) or maybe even the heater core but I doubt it. All the fuses are fine, none are blown. Unless I have a short some where or bad ground......