I have not seen my issue addressed in the many posts pertaining to blower issues.
Everything works fine and regulator checks out.
New motor today.
New regulator last year.
My blower will not reset. Every time I turn off car the heater fails to turn on again when I start it back up.
If I disconnect the three pin and reconnect each time it works perfect.
What could cause this?

Thank you for your help.

When you're Unplugging/Plugging in the "Three Pin" connector is the Engine On
with the HVAC set to Heat?

'Foggy,But IIRC
One wire is Ground (Black)
One wire is 12 Volt constant (Red)
One wire is the "Variable' voltage that controls Blower Speed. (Yellow)

__________________
'84 300SD sold
124.128

95 E320 Blower Stopped working Need help?

w124 94 E420 Climate Control Issue

Advanced Search for "Blower Connector/Arthur Dalton" yields:
http://www.peachparts.com/shopforum/search.php?searchid=5219075

Attached Thumbnails

   

__________________
'84 300SD sold
124.128

Might wanna get a spare junkyard CCU, might have a loose connection. Is this on hi and lo settings not just auto? Auto can sometimes have a 30 second like delay for sampling interior and exterior temps. Like when you go from vent to floor to defrost it takes a few seconds to change type of deal.

I have checked every connection point I know of and all seems well.
I have 14+ volts on red at 3 pin and fusable link when running.
I have variable volts on yellow depending on speed; 4+low/4+auto/9+high.

New Ign. switch.
new blower reg. last year
new blower yesterday

The only way the heater will work is if, when the key is in the on position with the heater on. I unplug the 3 pin connector wait 5 or 10 seconds, plug it back in.
Instantly blows!
Turn the key off.
Won't work.
I feel like I have followed the chain all the way down to blower reg.(which blows when Blue is grounded). All of your advice is greatly appreciated!

With big fan picture (high fan speed) pushed does it turn on when doing all your tests as the regulator will default full 12v+ to the blower motor. Just like when defrost is set position will default to max power.

In auto if the sampling motor behind passenger dash and the one under the wiper under the hood are referenced to tell regulator to change voltage to the motor.

There is no relay for the system. If it has to be reset there is something wrong with the CCU (climate control unit/pushbutton assembly) or that regulator is toast if it cant get voltage to the motor if the 3 pins at the tower are good voltage wise. I am pretty sure id bet its the regulator if its not bosch.

I feel youre pain. Good luck.

If all else fails change that fuse you just never know.

When I manually reset it by disconnecting 3pin I can run it through all speeds.
I works great!
My only issue is that when I turn the car off, the heater won't turn back on when the car is restarted.
I will go outside and check my voltages at the regulator Vs. 3 pin and see what I get.
Thank You!

Ok, when I test the Reg. Vs. 3 pin I get.
Big Fan Button SAME READINGS AT BOTH POINTS
Running- RED/14 Yellow/9.7 Blue/14
Car off Ign. on- Red/12.3 Yellow/8.5 Blue/12.3

Unplug 3 pin and plug back in:
At Reg. RED/12 YELLOW/9.2 BLUE/0 and the fan blows!

What do you think?

Ok there is the issue, blue is the ground for the system so why does it have power?


I am thinking the regulator may be shorted letting the power just go buy, with whatever switch is inside of it to vary the voltage.

If you look at your readings your blue when it doesnt work is matched to the full power of the red. That shuld never be the case.

isn't the 14 volts the problem right there? that doesn't point to the push button unit sending to much volts? if you are in nj by any chance i have an extra working push button unit u can try out to see if fixes it

__________________
1994 E320, 145,000 miles

Agreed, I have access to a wrecked 124 and am going to try both the CCU and Reg. this week. What do you think about running a ground to the Blue?

Thanks for all of your advice.
Max

Well while running 13-14 is pretty normal dont see that as a huge issue. If the rest of the car has that its an alternator issue, should be closer to 13.6 but 14 is not uncommon. Blower motor isnt getting more voltage than what the car has.

You could ground it but youre blue wire is hot at 14 volts would probably just short out.