When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Sorry for the delay I went away with the family for the new year. So I did a full flush of the heater core which didn’t really give me much results as not much came out of it junk or contamination. Then I went an extra step and did a thorough flush of the entire coolant system using ironite thoro-flush. The coolant color wasn’t as bad as I thought but still I didn’t get any heat from my vents at all. Then I remembered Botus saying that the rest button on the climate controller was for when the car was off and it would give off residual heat. So I pressed the button which stayed on for a whole 2 seconds and then shut. I rear ac vents but not a separate control panel for those vents btw blow even colder air out of them the dashboard vents. I also checked the fuses which are fine. So I have narrowed it down to 4 possible things. It’s the part right before change valve which is the auxiliary pump. The part Botus spoke about behind the front right wheel, the climate controller itself or lastly the climate control module. 2 of those parts I bought used with warranties which also have updated part #s from Mercedes. The auxiliary pump I was able to buy brand new and the part which Botus stated I will have to rebuild as I have YouTube video showing how to do it. Wish me luck as it’s becoming cold in NJ and it sucks driving with no heat. Plugging in the command didn’t make a difference..
the rest pumps pump coolant - I guess - mainly through the heater matrix.... so I suspect it may well get you heat (when working)
but I still think the main heater valve (black plastic bit beside the brake fluid reservoir) is electrically turned off - ONLY - because you don't have the comand system plugged in the car.....
my command is connected and still not heat. I was able to take out the (rest) auxiliary pump out but I am having a hell of a time getting the new one in. Anyone have instructions on install?
QUOTE=BOTUS;8907652]the rest pumps pump coolant - I guess - mainly through the heater matrix.... so I suspect it may well get you heat (when working)
but I still think the main heater valve (black plastic bit beside the brake fluid reservoir) is electrically turned off - ONLY - because you don't have the comand system plugged in the car.....[/QUOTE]
unless its got a valve to bypass surely a REST pump not moving would just be a nuisance for the cooling system - thus I don't think the coolant usually travels via the REST circuit (but never looked) , I thought the pump was just an extra to get additional flow when the engine is turned off
why not bypass the heater valve (in the short term) - as something isn't telling it to open from the sounds of it?
(with the car bolted up and connected as std) did you try with diagnostics resetting the madness of the HVAC system ? - multiple bits of user customisable madness available at dealer level fiddling - if they build in magic to turn OFF the AC unless you use dealer tools to reinstate - why wouldn't there be equal charge the customer madness for the heating....
that pump is a huge pain in the was to get out. There is a rubber mounting ring around it. I was able to get it out but putting in the new one is an even bigger pain in the ***. I have to try and figure it out today in 24 degree weather.
Originally Posted by BOTUS
unless its got a valve to bypass surely a REST pump not moving would just be a nuisance for the cooling system - thus I don't think the coolant usually travels via the REST circuit (but never looked) , I thought the pump was just an extra to get additional flow when the engine is turned off
why not bypass the heater valve (in the short term) - as something isn't telling it to open from the sounds of it?
(with the car bolted up and connected as std) did you try with diagnostics resetting the madness of the HVAC system ? - multiple bits of user customisable madness available at dealer level fiddling - if they build in magic to turn OFF the AC unless you use dealer tools to reinstate - why wouldn't there be equal charge the customer madness for the heating....
I'm looking at the heater valve ('170) - on a poor parts schematic - top port seems to be the rest pump (#10)... I wonder if the ARROWS I added, suggests something like the way the coolant MIGHT travel around the heater system with the heater matrix on the ends of pipes 180 and 190 ????
I guess if correct or there about - the pump is not a positive displacement pump and it allows the flow all the time...
So according to another forum member it’s what feeds the heater core.. any shot of you helping me with instructions to removing/installing the pump? I am having a really hard time getting in back in.
yep I was thinking re my picture possibly the correct idea but with arrows ALL back to front
sorry I don't have any instructions on the REST pump... not even sure where it is... its had to fathom why its difficult - is it a big circular mounting bracket... some heat / silicon lubricant ?
unless its got a valve to bypass surely a REST pump not moving would just be a nuisance for the cooling system - thus I don't think the coolant usually travels via the REST circuit (but never looked) , I thought the pump was just an extra to get additional flow when the engine is turned off
why not bypass the heater valve (in the short term) - as something isn't telling it to open from the sounds of it?
(with the car bolted up and connected as std) did you try with diagnostics resetting the madness of the HVAC system ? - multiple bits of user customisable madness available at dealer level fiddling - if they build in magic to turn OFF the AC unless you use dealer tools to reinstate - why wouldn't there be equal charge the customer madness for the heating....
.
I believe the REST pump is the one that allows the "Engine Residual Heat"-option to work, i.e., when you start the REST function from the button in the dash this pump circulates hot engine coolant thru the heater core and as the heater fan also runs it keeps the car warm for you when you return from a rest-stop, if the stop is not too long. Like if you need to stop for a quick rest room break you return to a warm car.
yep - in the pictures (with red and green arrows), I was trying to work out where the pipes and parts fit, and I changed my mind after the post you just replied to - [clb0099 then said my arrows were muddled (and I since updated both visions) it makes sense, as the pump probably does go in the that direction] - thus doing all that I think maybe all coolant for the heater circuit (or not) does go round the same circuit as the REST stuff
...FYI in post#53 the other valve you mention inside the front wing ( I don't believe you have it) - on parts drawings they show two drawings (both very similar) but this valve is not on the std cars - only on cars with option rear heater controls
Has anyone successfully removed/reinstalled the aux pump? I've got one coming, and was planning to do when I did the heater control valve. However after reading this thread, and looking more carefully at it, it looks impossible from what I can see. The plug connection is on the bottom. I can't even see the screws where it mounts. And I can find WIS instructions. I think I'm going to have to abandon that part unless someone has some good information on how to complete.
01-01-2024, 09:00 AM
