Topic: 1st Gen Mercedes ACCII Climate Control Servo: Less Expensive Replacement Option

[Blue300SD]

Re: 1960mog-
Thanks for your interest in the project! The kit is compatible with some w123’s that shipped with the 1st generation automatic climate control system. Just make sure your control panel looks like the one pictured and it will work (note the vertically stacked buttons).

My board receives three electronic inputs from the car: The sensor chain resistance, 12v ignition power, and a signal from defrost. Additionally, it receives a direct vacuum input line to control the heater valve, and then another vacuum source to control the vents inside the car (foot vents/ center vents).

Before you install the board, you need to make sure the vacuum on your car is pretty good (no worries if it’s not perfect, it should still work okay). In the gasoline models, look at the economy gauge at idle. It should be far to the left if your vacuum is good. Aside from that, if you take a vacuum gauge to one of the lines running from the passenger side to the driver’s side, you should be able to measure vacuum then do a leak down test.

One vacuum pod (#14 on r107, #19 on w116) controls whether the blower motor can come on or not. It is located behind the glovebox. If it leaks your blower motor will act like it's not working. Test this by trying to cut the blower motor on using the auto low/ hi functions. If it comes on, you’re good to go. If it doesn’t work but comes on when you hit DEF, then this vacuum pod is either leaking or not getting vacuum. The wires flowing into the pod can be bypassed and replaced with a toggle switch if your vacuum system is plagued with leaks (at your own risk).

The one other variable is the sensor chain. It is made up of a thumbwheel selector, ambient temperature sensor, and cabin temperature sensor. The goal of the climate control unit is to balance the selected temperature sensor with the cabin sensor. It is rare that these sensors fail, but more likely that they are out of calibration. However, my software was designed with that in mind. These are old cars, and thus their sensors are not accurate as new cars, so we created a greater margin of error that leans towards giving you hotter heat in the winter and cooler a/c in the summer
Thank you

P.S. Please let me know if I can offer you more assistance personally. I’d be happy to email with you/ talk over the phone to discuss specifics.

[alabbasi]

Nice effort. It looks like an old hard drive enclosure would would make a perfect housing and you'll get a small cooling fan to boot.

 

[daantjie]

I see these on ebay now, happy selling

[Blue300SD]

Daantjie + All-

Thank you for your support + advice during the development. With all your help, I was able to make very important revisions to the kit.

I have listed the unit for sale on eBay and on my website that I just set up, www.mercedesfix.com/products/climatecontrol. I've got a good number in stock that have tested out and are ready to ship. More are on the way!

To anyone who wants to order- I made a discount code as a thank you for all your help: W116FORUM. You can order on eBay or my website; the promo code only works on my website. Sorry if I sound like a salesperson!

I made a policy of 35-day returns for any reason and a 90-day replacement warranty. If anyone purchases it and needs repair advice/ climate control advice, don't hesitate to PM and I will give you my personal cell so we can discuss it over the phone.

I couldn't have done it without you guys! Not sure if this will wind up being profitable, but I sure enjoyed the development process Any future ideas for replacement kits are welcomed.

Take Care,
Davis

P.S. Becuase of the crazy weather here in NC, one day I would be using full heat, and then full a/c on another! I got to test it across the board.

[Zaxxon]

Now I am even more excited to take the W116 out of winter hibernation and start working on the A/C manifold/line. Because once that's fixed, I'll get one of these and hopefully have a functioning system this summer! Props and high 5's to you for coming up with a great product! Can't wait to hear some success stories!

--Zax

[Harv]

Everything looks great Davis.

Have you thought about making a video on an install? Obviously not two hours long, but just highlighting the main steps. Just throw it on Youtube. It's free marketing if someone runs across the video while searching 116/123/107 stuff then you can direct them to your website to buy.

[Blue300SD]

Harv-
That sounds like a good idea. I will try to pull the time together in one of the coming weekends to make that happen. Greatly appreciated!
-Davis

[avantbenz]

Your box looks great! How does it differ from other solutions available (if they still even are, that is) - like George Murphy's or Kent B from Mercedes Source?

I'm running a 1980 300SD and am definitely interested!

[xaliscomex]

Has anyone here on the forum purchased and installed one of these ACCII Climate Control replacement units?

A video showing the installation and how it works would really help in persuading people to buy it.

[thegreg92]

I ordered one last week and received it yesterday. It's not installed quite yet as I am in the process of overhauling/upgrading the entire climate control system. I'll post when its installed and how I made out

[Harv]

I ordered one last week and received it yesterday. It's not installed quite yet as I am in the process of overhauling/upgrading the entire climate control system. I'll post when its installed and how I made out

Do you think you can tackle it?

[xaliscomex]

What was the total price after using discount code and after shipping?

I need to make a decision on wether to go back to a rebuilt aluminum body Servo or move on to an alternative climate control system.

Questions to seller;

What happens if the climate control unit fails after a year of installing and using it?

Just wondering if you have some sort of idea on what you will be charging to repair your unit?

[daantjie]

Guys I don't want to be rude, but I think for this price this unit represents a fat bargain.  I get that we all want to pinch the pennies, but really the questions and grilling on this unit might have driven the developer away.  I mean do you really expect the seller to support this part into perpetuity?  If my ACC goes tits up I will for sure seek out this kind of setup.  Even if it does not work after a few years, it is still better than than you had with an inop ACC unit, no?  Granted, I live in a fairly mild climate, thus a perfectly working HVAC unit is not high on my list so I get why some of you are quite anal about this, I just think that it might be time to calibrate your expectations a bit here.
Friday rant over

[raueda1]

Guys I don't want to be rude, but I think for this price this unit represents a fat bargain.  I get that we all want to pinch the pennies, but really the questions and grilling on this unit might have driven the developer away.  I mean do you really expect the seller to support this part into perpetuity?  If my ACC goes tits up I will for sure seek out this kind of setup.  Even if it does not work after a few years, it is still better than than you had with an inop ACC unit, no?  Granted, I live in a fairly mild climate, thus a perfectly working HVAC unit is not high on my list so I get why some of you are quite anal about this, I just think that it might be time to calibrate your expectations a bit here.
Friday rant over

I was thinking the exact same thing.  Well said.

[Squiggle Dog]

Yeah, it's a fact of life that the ACCII system on the W116 is going to cause problems and repairs can be tedious. I think this setup is the way to go. Good for the seller for coming up with this design which greatly simplifies the system and makes it more reliable. Of course, I'd recommend converting to manual climate control, but that is such a huge undertaking in itself that it's not realistic for the average owner. If I were to have kept my ACCII, this is the way I would have gone. It seems the worst that could happen is the circuit board fries. In that case, it should be able to have the bad components replaced. Even then, I suspect it would last much longer than even an aluminum bodied servo.