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  #1  
Old 01-15-2012, 01:20 AM
79Mercy's Avatar
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ACC II Problems

I need to make a new thread on this as im stumped, i dont really know where to go from here.

Okay so about a month ago the climate control wouldn't heat or cool air, it just blew outside air through.

I found out the servo wasnt running when the temp wheel was moved. I check reistance on all sensors and the temp wheel. All measured within spec from the manual.

Still the amp wasnt sending power to the servo. Yes, there is power and ground at plug of amp.

I got a amp from George Murphy, SAME problem, servo will not run by itself.

I tested the servo and the resistance is spot on in all positions according to the manual.

Im stumped, i dont know where to go from here. I cant find the problem, everything seems to test okay.

Thank you

__________________
1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg
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  #2  
Old 01-15-2012, 01:34 AM
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Two points

* What vehicle (for those who don't know).
* Please at least add a link to the old thread, so we don't suggest duplicate basic testing.


Thank you.
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  #3  
Old 01-15-2012, 01:38 AM
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Well its on my 79 280CE, any 1977-80 W123(except euro and 240D), W116(except euro), and 1977-1982 on the R107.

It wasnt my thread, i just kinda jumped in at the end to see if anyone could help: http://www.peachparts.com/shopforum/diesel-discussion/304961-its-heater-season-acc-fun-2.html

If anyone has any ideas please post, im stumped
__________________
1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg
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  #4  
Old 01-15-2012, 02:18 AM
whunter's Avatar
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Location: Metro Detroit, Michigan
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Hmm

Have you checked the heat box temperature switch?
MB# 0028211851

.
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ACC II Problems-evil-servo-temp-switch_0028211851_avqnezofsk.jpg  
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  #5  
Old 01-15-2012, 04:49 PM
79Mercy's Avatar
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Location: Florida
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I haven't, anyway to bypass that switch? Is that what we would call the evap temp sensor?
__________________
1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg
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  #6  
Old 01-15-2012, 10:11 PM
whunter's Avatar
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Join Date: Dec 2003
Location: Metro Detroit, Michigan
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Answer

Quote:
Originally Posted by 79Mercy View Post
I haven't, anyway to bypass that switch? Is that what we would call the evap temp sensor?
It is the heater box temperature sensor/switch.

Try jumping the pins.

The switch lists as $210.00 each.
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  #7  
Old 01-15-2012, 10:34 PM
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Join Date: Mar 2008
Location: Florida
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Im gonna look into that in my wire diagram and see how and if that ties into the amplifier and or servo wiring. Thank you
__________________
1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg
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  #8  
Old 01-15-2012, 11:10 PM
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Join Date: Mar 2008
Location: Florida
Posts: 4,131
I have been studying the wire diagram for this, i have been able to check and test all but one wire at the amp it seems. Looking at this diagram, PIN 2 at the amplifier(6) goes to the pushbutton unit(2). Can anyone tell what this wire does, could it cause me problems?

__________________
1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg
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  #9  
Old 01-16-2012, 03:39 PM
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Join Date: Mar 2008
Location: Florida
Posts: 4,131
Did more testing today. The servo and its feedback are perfect, no open spots, and resistance values are within spec.

If i manually run the servo away from "park" from the battery with jumper wires and then plug the servo back in, it will run back to "park" properly.

That relay i mention in the last post is for the defrost, it tests fine.

Ambient temp and in-car temp sensors ohm within spec.

The only thing that was slightly out was when i measured the "sensor chain". Pins 3 nad 4 of the amp plug.

I measured 4500 ohms,temp wheel at 65(spec is 2000+/- 1000 ohms)

I got 5500 ohms,temp wheel at 85 (spec is 3500+/- 1000 ohms)

The real problem is that the amp refuses to drive the servo when i move the temp wheel.
__________________
1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg
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  #10  
Old 01-17-2012, 05:57 PM
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Join Date: Mar 2008
Location: Florida
Posts: 4,131
to add a bit of closure to this strange thread. Turns out pin 8 of the amp had voltage, but when under load it fell off completely. I ran another 12V switched wire to that and tapped into that wire to supply it with voltage and presto, everything works perfectly, even my new(used) aux water pump.

__________________
1985 300TD Turbo Euro-wagon
1979 280CE 225,200 miles
1985 300D Turbo 264,000 miles
1976 240D 190,000 miles
1979 300TD 220,000

GONE but not forgotten
1976 300D 195,300 miles
1983 300D Turbo 175,000 miles

http://i42.photobucket.com/albums/e3...e485-1-2-1.jpg
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