I asked a couple of questions on the weekend, but decided to start a new thread with a more appropriate title as this may turn into a longer thread.

Background: I have the classic ACC II problem: only works on defrost.

Servo and amplifier are both brand new. (Yeah I started out doing plug and... hoping for an easy one-shot fix... twice.) The control panel looks pretty new.

I am using the factory manual but I started by using some troubleshooting notes posted quite a while ago, I believe by Doktor Bert (I saved them but didn't save a name).

I started out checking the connector to the amp. No power with the key off (pin #6 should have battery power at all times).

Read for the first time about the 2A fuse, another lister helped me find it (inline holder with relays on inner fender). Fuse missing from holder. Wasted a lot of time trying to find the correct tiny fuse, no luck, so spliced in a new holder big enough for more modern fuse.

As soon as I did this, I got bi-level functioning, but only if I first selected defrost for a few seconds, then pushed the bi-level button. Worked for about 20 minutes, then died again. The fuse is fine. Now back to defrost only.

I now have a few days before I get back to it. Any suggestions, based on what happened so far? Otherwise it's back to the list.

Thx

__________________


Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

I am no expert on these. My ACCII has been working OK since I bought the car a few years ago besides the lack of A/C due to no pressure in the system.

But my blower isn't that healthy. Kind of squeaky. I sometimes have a similar situation in which it would only start on the defrost setting and then would sometimes work afterwards if you switched to another setting. Sometimes however it would only work in defrost.

The general consensus of what I read was that this is often caused by a blower with heavily worn brushes. It takes the full voltage applied under defrost, which by design kicks the blower in to high speed, to get the blower going. Once moving it then may work at lower voltages as the system adjusts fan speed to control temp.

It's one idea anyway.

__________________
1979 300D 040 Black on Black - 1985 300D Maaco job (sadly sprayed over 199 Black Pearl Metallic) on Palamino

http://i.imgur.com/LslW733.jpg

The Baja Arizona Oil Burners Send a message if you'd like to join the fun
Left to Right - UberWasser, Iridium, Stuttgart-->Seattle,, mannys9130

Visit the W123 page on iFixit for over 70 helpful DIY guides!

Make sure your aux water pump is unfrozen and or disconnected.

Now if you set it on 65 it should come on, hi/lo bi level should come one with deforest..

If you don't have the sensor tube connected, the system won't know when to turn on. If you want heat, you must wait for the thermostat to open on the bottom of the servo to allow vacuum to the system....if you don't want to wait for it to get to the correct water temp....simply connect the two red vac lines on going to the bottom of the servo together.

This post will tell you how to test the resistor chain, that the system uses to tell the tempature

http://www.peachparts.com/shopforum/1681287-post5.html

__________________

Check the green/yellow vacuum supply. It will only do defrost if the vacuum is low.

__________________
Current fleet
2006 E320 CDI
1992 300D - 5speed manual swapped

former members
1984 300D "Blues Mobile"

1978 300CD "El Toro"

Will address all these points.

BTW, I should have been clear that right now the servo isn't moving at all as far as I can tell. For sure it doesn't 'park' when the power is turned off.

Tks

__________________


Mac
2002 e320 4matic estate│1985 300d│1980 300td
Previous: 1979 & 1982 & 1983 300sd │ 1982 240d

“Let's take a drive into the middle of nowhere with a packet of Marlboro lights and talk about our lives.” ― Joseph Heller, Catch-22

You can always use a 9v battery to test the small motor in the servo to confirm it does work...

__________________