A/C CLIMATE CONTROL UNIT PROBLEM OR MORE

Have '91 MB 420 SEL with failed A/C problem. Replaced Climate Control Unit & A/C Relay and still compressor doesnt kick in nor blower. Checked & replaced #5 Fuse with New One.............back-up lights is
in this group functions & the lights come-on with gear shift in reverse. Pushed in A/C control unit buttons to activate the A/C & nothing happens....engine is on and compressor doesnt come-on. Coincidentally, my turn signal doesnt blink........is this a related problem or WHAT? Anybody out there, I need HELP !! All sugestions and assistance is greatly appreciated!!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
You probably got low refrigerant... it would never let you run AC if your refrigerant is low. Make sure all the wires at the A/C drier is hooked up... front driver side next to radiator... round cylinder thing... behind headlight.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Do you have any info on where to find the Flasher, since my signal lights dont light-up nor blink? I will check out the refrigerant level later this afternoon......Thank you!!
Tiger wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
I suggest you take the fuse out and replace it for the flasher... it is usually the fuse... it look deceptive when in place. I never changed any flasher on MB... it is not like US cars that flasher goes bad.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Tiger wrote:

Low refrigerant would account for the compressor not running, but what about the blower? He says that doesn't run either. Does anything work? How about heat?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Regarding the AC unit, no blower activation, no compressor & no heat that I can feel with hand on vent. Fuse @ #5 changed and all wires at Dryer connected. Yet to check for Freon level in the system. What instrument or divise is used & instructions to accomplish the check. Does anyone out there have infor for me???
snipped-for-privacy@optonline.net wrote:

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Blower is also due to age of the car... They usually crap out at about 16 years old. Not bad for original blower motor...
I would check freon level... change all the fuse related and then diagnose further.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Tiger wrote:

Why should he be looking at freon, when the blower doesn't even run and there is nothing working? The blower should run without the compressor starting. It should also run to supply heat. Apparently none of that is happening, so I wouldn't be worried about refrigerant level at the moment, as at a minimum something else is wrong. And whatever it is, that may be all that is wrong.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

I'm glad to see somebody is thinking.
Put 12V and GND to the fan/blower connector. If it spins, it's good and there's a 99% chance your pushbutton switch asembly is bad. That seems to be the bit that always fails. They're like $300 rebuilt, don't even ask about new ones but you can usually get a working good one for about $50 off flea-bay or a wrecking yard. try car-part.com for wrecking yards.
The defrost setting is the benchmark. It should rnu full fan and full heat, period. It that doesn't work the pushbutton assembly itself is always the first thing to check. No power getting to the far on defrost is an almost sure sign the pushbutton assembly needs replacing.
--
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.