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!!
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
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.
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???
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
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.
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
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
Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
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