80SD ACC blower speed resistors HELP - PeachParts Mercedes-Benz Forum

1980sd · #1 04-25-2011, 04:38 PM

I'm not even trying to get the system to function as designed. Just trying to get some AC/Heat going...

I have it so now it blows out all the front registers and the defrost vents. It seems like my flappers are mostly toast because manual flipping of the ones I can get to don't seem to do much.

I'm trying to get different blower speeds but I can't seem to find any resistors and I don't notice any heavy gauge wires coming out of the ACC amp.

If it uses resistors could someone point me in the direction. I have a 2 prong plug coming from the blower with 3 wires going to it which I assume is coming from some switched resistors.

I was going to abandon the ACC control with a switch panel.

If it doesn't use any resistors which could be "harvested" could someone help me with what values would work. I'm thinking some sort of 3 way switch from RS with resistors would be quick and dirty.

Thanks

vstech · #2 04-25-2011, 08:07 PM

is this in an 80SD like your username suggests?
should be a metal box in the engine bay, with coils of wire in them. that should be the speed resistor box. no idea where it is on a 116

1980sd · #3 04-25-2011, 08:36 PM

Yes, 1980 300SD. I poked around the engine bay and didn't see it. I don't suppose it's in the box with the glow plug relay?

79Mercy · #4 04-25-2011, 08:37 PM

I have a feeling its built into the push button unit on the ACCII cars. I cannot fiund the resistors on my 79 280ce either.

vstech · #5 04-25-2011, 08:44 PM

ouch. could be part of the evil servo I suppose...

Ether · #6 04-25-2011, 10:06 PM

I'm not sure where the blower divider resistors are located but according to the electrical diagram there are 3 55 watt, a 25 watt and a 15 watt so they are fairly decent in size.

You wanna have some real fun? (if you're a masochist) Head over to w116.org and spend some time staring at the climate control diagrams in the Service Manual. The ACC II climate control system woulda made Rube Goldberg blush.

ridgerunner · #7 04-26-2011, 12:54 AM

Isn't the resistors below the brake master cylinder/brake booster in no mans land? This is where it is critical to keep it clean because of starting fires.

vstech · #8 04-26-2011, 08:44 AM

Quote:

Originally Posted by ridgerunner

Isn't the resistors below the brake master cylinder/brake booster in no mans land? This is where it is critical to keep it clean because of starting fires.

on a 126, yes... OP has a 116. I do not know if it's there on a 116.

kerry · #9 04-26-2011, 09:31 AM

My 116 is sold but my recollection is that the resistors are on the right inner fender.
Doktor Bert(?) had a post a few months ago pointing out that poor ground to the blower motor on a 116 causes problems with the system. Can't recall exactly what kind of problems but he did install a separate ground I think.
If you search on my user name and 'servo manual' I have a post here with a link to the online servo manual.

Doktor Bert · #10 04-26-2011, 04:35 PM

The resistor group on a W116 is under the aluminum grille at the base of the windshield. There is a black, multi-pin connector on the firewall that connectes the resistor group to the wiring harness. You can check the values without removing the grille through the plug in.

There are (4) special, plastic rivets that hold the grille in place. The rivets will likely be destroyed when you remove the grille. they are available from MBZ (and others) under P/N 000-990-22-92 and cost about $2.00/each.

There is a double-pole blower relay behind the glovebox. Check this by wiggling the connector with the CC II in 'Auto Hi.' If the blower speeds up, disasemble the relay (by prying the metal crimp away from the plastic floorplate) and file the contacts until they are flat with a nail file, or other instrument, or replacing it with a new one.

SOME 116's (like mine with an early chassis number of 000433) have a ground wire that 'breaks out' of the harness and attaches to the relay mounting screw. be sure this is tight IF your car has it. many of the later ones DO NOT have this 'pigtail.'

Poor contact alignment causes high current draw and low blower speeds, blown fuses, etc.

Keep in mind that the servo and the amplifier will have an influence on your blower speeds....

Doktor Bert · #11 04-26-2011, 04:41 PM

W116 CC II FSM:

http://handbook.w116.org/climate_78_3d.htm

Doktor Bert · #12 04-26-2011, 04:45 PM

Quote:

Originally Posted by Ether

You wanna have some real fun? (if you're a masochist) Head over to w116.org and spend some time staring at the climate control diagrams in the Service Manual. The ACC II climate control system woulda made Rube Goldberg blush.

Yes, the diagram is quite intimidating, but the CC II system is realy misunderstood.

Most of the problems come from a bad CC amplifier, bad blower relay and bad auxillary water pump.

The #1 cause of servo replacement, blowing the #3 and #9 fuses is caused by a shorted A/C low pressure switch in the drier.

I cannot even begin to describe how many servos I collect from the junkyard that work!!!!

Doktor Bert · #13 04-27-2011, 04:37 PM

Get it figured out????

1980sd · #14 04-27-2011, 04:55 PM

No, I'm about to go fool with it. I have 2 project cars now which is probably not the best position to be in. I'm slow and scatterbrained enough already!

Great info though Bert! And thanks a million!

I'm going to bodge the older AC system but I plan on throwing $$ at the low mileage one.

Doktor Bert · #15 04-28-2011, 04:03 PM

You are welcome!!!!