View of 107 ACC Modules

[Walrus]

You have to be careful what you call or interpret MAX... at MAx, you engage a detent, which bypasses the control function of the temp wheel...

[ctaylor738]

Thanks for checking.

I am puzzled, though, how the temp relay would figure out whether to go to max heat or no heat if the min/max reading is the same.

I did measure MAX with the detent "engaged." It was reading 8.1 k ohm at 26 just befor the detent.

[ctaylor738]

Decided that since the temp wheel was getting reasonable readings in the mid settings that this was not the worst problem.

So I sprung for a NOS temp control unit on e-Bay, and installed it last night. Not exactly a fun job, especially getting the 12-pin connector unhooked.

The results were "an improvement." I no longer have only full heat, and I do have some control over temperature. But it's still not right. It still will not blow cold air despite a 45 degree outside temp.

I did find another problem. The recirculating flaps seem to be stuck in the closed position, and I will open another thread on this problem.

[Kimolaoha]

Originally Posted by ctaylor738

Decided that since the temp wheel was getting reasonable readings in the mid settings that this was not the worst problem.

So I sprung for a NOS temp control unit on e-Bay, and installed it last night. Not exactly a fun job, especially getting the 12-pin connector unhooked.

The results were "an improvement." I no longer have only full heat, and I do have some control over temperature. But it's still not right. It still will not blow cold air despite a 45 degree outside temp.

I did find another problem. The recirculating flaps seem to be stuck in the closed position, and I will open another thread on this problem.

Chuck -
Sorry to hear that this did not completely solve your problems.
As I'm also about to swap out my temperature regulator, can you elaborate on the issues you had with the connector? When I was last in there, it looked to be pretty straightforward, but now I'm concerned.
Also, did you/do you have cold air when you put the temp wheel past the cold detente? What do you mean by "some control over temperature" -- does your temp wheel respond at all?
Mike

[ctaylor738]

There is still no temp control, it is stuck on full hot.

So I looked closely at the wiring diagram. The monovalve closes when it gets ground from the temp relay. The path of the ground is from the temp relay through the control unit in EC, Normal or TV, then through the temp wheel not in full hot or cold. I checked the continuity of that path and there is only a sproradic connection from the control unit to the monovalve ground that doesn't change as the temp wheel is moved. So I am thinking that is the next thing to repair or replace.

What I meant about the connector is that it is twelve big pins that haven't moved in a while in a tight space with not much leverage. I ended up working a small screwdriver in between the connector and the relay to get it started.

[lynns]

Originally Posted by ctaylor738

There is still no temp control, it is stuck on full hot.

When was the last time that you replaced the mono valve? Have you replaced the center vent acuator?

[ctaylor738]

I replaced the monovalve two years and a couple of thousand miles ago as the first step in trying to fix this. It seems to work fine. It closes when the OFF button is pushed, and I can close it by grounding it.

All of the actuators hold vacuum and are connected. The vacuum distributor seems to be sending vacuum to the right places when the buttons are pushed. I'm not aware of any effect that the center actuator would have on temperature - if there is one, please explain.

The issue seems to be that when the system in on - any button pushed - the monovalve is not getting a ground signal. It is supposed pulse on and off in 5 second intervals. What I tried to say in the previous post is that the temp relay supplies the ground via the temp wheel and push-button unit. So either the relay is not doing its thing (unlikely since its new) or there's a fault in the transmission path.

The sixty-four dollar question is how can you tell. I think I'll chase the temp wheel, since its resistance readings were suspect.

[lynns]

Originally Posted by ctaylor738

I replaced the monovalve two years and a couple of thousand miles ago as the first step in trying to fix this. It seems to work fine. It closes when the OFF button is pushed, and I can close it by grounding it.

I asked the date of when you installed the mono valve last because I like yourself was having a similar problem and thought that because the valve had been replaced that that was not the problem and told my Indy that after much confusion. Similar to what your going through. So he did'nt take my word for it, thank God, and installed a new valve and Viola the problem was fixed and he let me know in no uncertain terms what he thought about me replacing mine such a short time ago. FWIW, by the time I had finished with two different R107's I had replaced these valves multiple times on each of the cars.

[ctaylor738]

I have a 1985 380SL in rehab, with working climate control. Earlier, I had tried swapping push-button units, with no effect.

So, with no other alternative, I thought I would re-try this with the new temp relay. This made the heat control work perfectly. So I would say the diagnosis is like that TV commercial for the cholestorol/blood pressure medicine - "sometimes problems come in two's."

BTW - this can't be a permanent swap because the 560 unit sends ground rather than positive to the AC relay. But you can use it to test the heat if you stay on the EC setting.

[Kimolaoha]

I too have FINALLY had success.
As was one of Chuck's dual problems, my temperature regulator had gone bad, and a swap with a working used replacement seems to have finally solved my issue. For the record, my issue was no incremental thermostat response from the control unit temperature select wheel (described in more detail below). Referring to Chuck's picture in the very first post of this thread, the temperature regulator is the silver box behind the black box, and is annotated as # 3 in the picture.
For those who are troubleshooting their own issues and happen to come upon this thread in a future search, here are my details as well as the MB and Bosch part numbers for the temperature regulator (also often referred to as the climate control amplifier):
Mercedes Benz part number 000 822 1003 (Note that the numbers at the top of the box are the Bosch part numbers -- 1 147 328 025).
Issue: I have an ’83 380 SL with the Tempmatic climate control system. Up until the beginning of this season, all seemed well with the climate control system, i.e. air from all vents per spec, temp wheel controlled the temp just fine, blower speeds OK. No issues.
At the beginning of this season, though, I noticed that the temp wheel has stopped functioning correctly, and I now get full hot air in every position except the full cold past the détente position, where I do get full cold. All other settings revert to full hot.
I assumed it was the monovalve (a common problem) and bought and installed the repair kit, but was surprised to find that the existing monovalve was in fine shape. Not surprisingly, this attempted fix made no difference.
I then purchased a new in dash temp sensor and tried that. The previously replaced hose from the existing sensor was still connected, and the new sensor made no difference.
I then found a new old stock control panel on eBay for a decent price, and installed that (the panel with the pushbuttons and temp wheel). Again, it made no difference. Bummer.
During the summer, this was not that much of a problem, though, as I always kept the A/C at full cold anyway.
But now, with the weather cooling down, I don’t want full cold -- but I don’t want full hot either. Also, the fact that it is not working correctly just bugs me.
Thus, my next idea is to swap out the Temp Regulator/Climate control Amp and see if that makes a difference.
Thankfully, this idea was the one that finally paid off. Note that there was a lot of very noticeable clicking back where the amp is located -- presumably as the bad amp tried in vain to function. The new (used, courtesy of eBay) amp only clicks periodically -- when it is sending a signal, as it should.
Finally, while I suppose it is possible to access the amp by simply removing the glove box liner and working through the cavity, I found it much easier to get access by first removing the passengers knee panel below the glove box (2 10mm nuts and one screw).
Hope this helps someone down the line.
Mike

[ctaylor738]

Well done.

I replaced my temp control unit with Bosch 1 147 328 029, which according to Ron at German Star is interchangeable with 1 147 328 025.

[lynns]

Originally Posted by ctaylor738

Well done.

I replaced my temp control unit with Bosch 1 147 328 029, which according to Ron at German Star is interchangeable with 1 147 328 025.

Did you buy a new one, rebuilt, or used?
What did the part cost you?
What was the M-B p/n?

[ctaylor738]

I paid $70 for a new NOS 029 temp regulator unit on eBay.

I don't recall the MB #.

[Kimolaoha]

Originally Posted by lynns

Did you buy a new one, rebuilt, or used?
What did the part cost you?
What was the M-B p/n?

M-B p/n 000 822 1003 (the blower regulator is 000 822 1103)
Mine was used from eBay.
They go from $15 to about $70 there.

[ctaylor738]

So after being distracted by the idle and mixture problems on my project 380, I finally ordered a rebuilt ProgRama control unit - $178.59 and free ground shipping - from ********AZ. It arrived on Friday, and I installed it yesterday. I am very happy to report that I now can regulate the heat and cooling.

This was a long battle. The car needed the following:

- dash sensor
- foam hose from dash sensor to blower chamber
- temperature regulator
- control unit

The ProgRama rebuild came with some interesting troubleshooting tips, which I'll put in a separate post.