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New Climate Control regulator valve misbehaving

Started by Rolo, 31 May 2023, 11:11 AM

Rolo

I got one of the new electronic regulator valves to replace a leaking aluminum body valve that only lasted about 40k miles.


The new one is doing odd things like switching between cooling and heating while the car is pretty hot.  It's as if the system overshoots the cooling temperature and then heats to bring it back down.  In cooling mode, it will also start blowing hot air through the side vents and cool air through the center vents as if it was switched to Bi Level.

I don't think I'm getting the same high fan speeds I was automatically getting in Auto Low mode anymore.

Anyone else with the new Climate Contol value with similar experience?  Thanks

daantjie

You might want to post a pic or link to the setup you have.  There have been a few iterations of replacements for the ACC system to my knowledge.
Daniel
1977 450 SEL 6.9 - Astralsilber

Rolo

Very annoying and uncomfortable.  Switches from heat (too high) to cooling (too low) and back.

amilio

What vendor made your new electronic unit? This thread has some details on the Hamilton unit:

You may need to reset the sensor chain: https://handbook.w116.org/cd/Climate/83-611.pdf


My unit has odd behavior because of the wrong resistor, as mentioned in the first thread. Hopefully having an electronics shop replacing it soon, but the car's current caretaker is wary of putting all the small vacuum lines back on after.
1979 300 SD "Liesel", 282k Miles

Rolo

Thank you for posting the links.  I read through, and what I'm experiencing are fluctuating modes between hot and cold.  It's annoying.  There is one condition that is miserable.  Unit switches to high side vent heat and shuts off center vents while set for cooling.

amilio

I guess my only other troubleshooting steps would be to check the wiring job behind the glovebox where the amplifier used to be and ensure there are no shorts. Other than that, you may have a detective unit. Who made your unit?
1979 300 SD "Liesel", 282k Miles

Rolo

Thanks for the suggestions

I believe it's the Hamilton

daantjie

Not sure really how to assist as I am not sure if the tests with the ACC will work here.  But on the ACC system if you unplug for example one of the sensors like the ambient sensor at the firewall, then the resistance goes open, and then you should get full hot.  Another failure spot is the "sniffer tube" which runs to the in car sensor.  On many older cars this tube is rotten away, thus causing lazy and imprecise temp adjustements.  These are as I said easy checks on the old ACC system and not sure if this will help you with this newer iteration.
Daniel
1977 450 SEL 6.9 - Astralsilber

Rolo

Thanks for the tips.

The sniffer tube and sensor were all good before the regulator valve started leaking vacuum.

I'm tempted to have the old valve rebuilt and re-installed.  But, that unit only lasted 40,000 miles.  It's the aftermarket aluminum bodied type.

Rolo

So here's some more of the odd behavior.  For those with this unit installed, maybe you can advise if normal for the Hamilton, or if I have to have it looked at:

Cold motor, cool weather: Auto Low immediately goes to highest fan speed, blows cold air (this is not the way the OEM unit runs)
Cool weather: In Auto Low, heat runs with high fan speed, gets too hot, switches to cooling on high fan speed, then back to heat on low fan speed.

The OEM unit was really quite good while it ran.

JeffCullen

I've had the Hamilton setup in my car for over 3 years. Perhaps I got lucky, but mine works great!
1979 300SD #6680 - Astralsilber - 153,750km
1998 E300 Turbodiesel - Rauchsilber - 172,000km

Rolo

This was too easy (for the shop).  The they managed to disconnect the tube to the temp sensor so it was taking readings from inside the dashboard, not cabin air.  Still, different operation than OEM which is disappointing given the ad copy Hamilton posts on their website.

But if it lasts longer than 40,000 miles, I'll be happy.

sutekh

Hi @Rolo, glad to hear connecting the temp sensor vac line has improved the situation. Your first pic of the unit with the exposed PCB connectors doesn't look quite like the same packaging of my Hamilton units. We're sure that's a Hamilton, and not an Unwired Tools (there are a couple others as well)?

If it is a Hamilton, I'd be happy to help you further diagnose and try to achieve original operation. As outlined in the thread @amilio linked above, I effectively reverse engineered their complete system and have had a lot of dialog with their engineers. By default, they only include 2 solenoids (although the board is wired and programmed for 3) which means you don't get the same OE leg / panel vent differentiation. They claim this is due to customer preference.

Rolo

Thank for the offer and the observation about the unit not being a Hamilton.  It was sourced from a distributor, so I can't be certain of who manufactured.

Here is one question for Hamilton owners.  With the OEM and the aftermarket aluminum-bodied OEM clone, I had 4 fan speeds, 2 in Auto High and 2 in Auto Low.

How many fan speeds does the Hamilton provide?  Thanks so much.

sutekh

Quote from: Rolo on 24 July 2023, 02:08 PMHere is one question for Hamilton owners.  With the OEM and the aftermarket aluminum-bodied OEM clone, I had 4 fan speeds, 2 in Auto High and 2 in Auto Low.

Based on what I see in your small pic, it looks to me like the later version of the Unwired Tools part (E.g., https://www.ebay.com/itm/353357938109). Even though their product photos suggest otherwise, neither UT nor Hamilton use aluminum housings on their current variants.

As for fan speeds, the Hamilton attempts to faithfully emulate the original ACCII servo and emulates all 4 OE fan speeds. I can't say for the UT I'm afraid.