Everything buttoned up correctly and... NO BLOWER ON ANY SETTING! I disconnect the fan wire and replug the fan plugs onto the servo, I can make the servo transit from hot to cool with the temp wheel, but NO FAN!

With a discription like that. lol




1. Check all fuses in the fuse panel in the Right Hand (RH) kick panel, also the in-line fuses located directly above the fuse panel for the AC amplifier.

2. If all OK, then verify power inputs to the AC amplifier located behind the glove box.

3. Using a Digital Multimeter, (DMM) Pin #6 on the amplifier the Red/Yellow/Green (RD/YL/GN) wire should be battery voltage (B+) at all times. Pin #8 on the amplifier Black/Pink/White (BK/PK/WT) wire should be B+ with the key in the on position from AC/start relay. Pin #4 Brown (BN) wire should be a constant ground. Pin #2 White (WT) wire should be B+ with the key on and control panel pushbutton in the DEFROST position.

2. By backprobing the connector across terminals #1 Green/Yellow (GN/YL) and #7 Black/Violet/White (BK/VI/WT) with the DMM leads, check for voltage output while switching the temperature selector wheel between hot and cold, with Key On Engine Running (KOER). The amplifier is capable of reversing the polarity output on these wires to the servo motor so the polarity of the DMM connections is unimportant. As the temperature selector is adjusted, the voltage output on these wires should change. This indicates a correctly functioning amplifier. If there is no change in the temperature or airflow, then the servo is stuck or shorted/open circuit.

And if that doesnt work, go to this.

1. Check vacuum supply to pushbutton switch on control panel from engine key on engine running.

2. Test power feed into climate control amplifier behind glove box using a Digital Multimeter (DMM). Pin #8 Black/Pink/White wire should be Battery Positive Voltage (B+), Pin #6 Red/Yellow/Green should be B+ key on from in-line fuse. Pin #4 Brown is ground. Pin #2 White wire should have B+ when mode switch is in Defrost position.

3. Start engine and disconnect connector at amplifier. Use a fused (5A) jumper wire from B+ to connect to Green/Yellow wire at connector, and from ground to Black/Violet/White wire at the connector. This applies voltage directly to the drive motor in the servo. After a few seconds the temperature should change. If not, reverse polarity and retest. If there is no temperature change, the servo is defective.


And if none of that works. Heaven forbid.

1. With key on, select different temperature on climate control panel while listening for climate control servo motor operation. If servo motor does not run, diagnosis of servo needs to be performed.

2. With servo operating test of main blower vacuum switch is needed. Remove climate control panel and find main vacuum switch. It has a green vacuum line attached to it and it is to the far right of the four vacuum switches. Remove wiring connectors from switch and jump them together. Wire colors are Green/Yellow and Green/Yellow/Red. With key on does blower run at low speed?

3. Test for vacuum to switch with engine running. If vacuum is correct and blower runs with switch by-passed, the switch is faulty.

 

Some of this already done, so I will respond individually in context. Others sound like good checks to perform, and will be top on the list:

With a discription like that. lol

Luck, I'm gonna need...

1. Check all fuses in the fuse panel in the Right Hand (RH) kick panel, also the in-line fuses located directly above the fuse panel for the AC amplifier.

Done. All good, including 2A in separate holder, and verified by DMM, not just visual.

2. If all OK, then verify power inputs to the AC amplifier located behind the glove box.

Done

3. Using a Digital Multimeter, (DMM) Pin #6 on the amplifier the Red/Yellow/Green (RD/YL/GN) wire should be battery voltage (B+) at all times. Pin #8 on the amplifier Black/Pink/White (BK/PK/WT) wire should be B+ with the key in the on position from AC/start relay. Pin #4 Brown (BN) wire should be a constant ground. Pin #2 White (WT) wire should be B+ with the key on and control panel pushbutton in the DEFROST position.

2. By backprobing the connector across terminals #1 Green/Yellow (GN/YL) and #7 Black/Violet/White (BK/VI/WT) with the DMM leads, check for voltage output while switching the temperature selector wheel between hot and cold, with Key On Engine Running (KOER). The amplifier is capable of reversing the polarity output on these wires to the servo motor so the polarity of the DMM connections is unimportant. As the temperature selector is adjusted, the voltage output on these wires should change. This indicates a correctly functioning amplifier. If there is no change in the temperature or airflow, then the servo is stuck or shorted/open circuit.

Will check with this procedure, but be advised: With all connections restored as factory, the servo will transit from hot to cold in Bi-Level, etc with rotation of temp wheel. Verified with top off of servo and watching pot rotate, and temp of air change with rotation. Servo parks correctly in all cases. Fan just will not run. In bypass and on bi-level, fan will not turn on until vacuum switch makes, shortly after engine running. Heavy acceleration and vacuum drops, so fan shuts off briefly until vacuum restores. Indicates vacuum leak, but not bad enough to prevent function at idle or moderate acceleration.

And if that doesnt work, go to this.

1. Check vacuum supply to pushbutton switch on control panel from engine key on engine running.

vacuum present... all flaps change as per design when running on my bypass...

2. Test power feed into climate control amplifier behind glove box using a Digital Multimeter (DMM). Pin #8 Black/Pink/White wire should be Battery Positive Voltage (B+), Pin #6 Red/Yellow/Green should be B+ key on from in-line fuse. Pin #4 Brown is ground. Pin #2 White wire should have B+ when mode switch is in Defrost position./

will verify as instructed, but be advised as per above function when hooked back up per factory.

3. Start engine and disconnect connector at amplifier. Use a fused (5A) jumper wire from B+ to connect to Green/Yellow wire at connector, and from ground to Black/Violet/White wire at the connector. This applies voltage directly to the drive motor in the servo. After a few seconds the temperature should change. If not, reverse polarity and retest. If there is no temperature change, the servo is defective.

I believe I have confirmed servo is functioning properly with above information.

And if none of that works. Heaven forbid.

1. With key on, select different temperature on climate control panel while listening for climate control servo motor operation. If servo motor does not run, diagnosis of servo needs to be performed.

As indicated from info above, servo appears to function. Def is hot, and servo parks when ignition shut off, visually verified by watching pot turn. In bypass, air transits from hot to (park) cool when switched to bi-level... sounds like dead amp or loss of power to amp when switched to bi-level, etc. When hooked up per factory, recall that the servo will transit from hot to cool, past park (I marked spots on pot case as reference).

2. With servo operating test of main blower vacuum switch is needed. Remove climate control panel and find main vacuum switch. It has a green vacuum line attached to it and it is to the far right of the four vacuum switches. Remove wiring connectors from switch and jump them together. Wire colors are Green/Yellow and Green/Yellow/Red. With key on does blower run at low speed?

#19 I presume (master switch)... Verified vacuum is closing this switch from previous test, I believe.

3. Test for vacuum to switch with engine running. If vacuum is correct and blower runs with switch by-passed, the switch is faulty.

Will test #19 as per your instructions regardless, but be advised: In bypass, I can remove vacuum (unplug black vacuum line on the thermo on the bottom of the servo) and the fan will cut off, indicating #19 master switch is closing with vacuum.

Whew...!
Thanks

 

Sorry I forgot one.





1. Check engine for any vacuum leaks. Check for vacuum supplied to port #6 of pushbutton vacuum switch on rear of control panel, green or green/yellow vacuum hose, with key on engine running (KOER). Minimum spec is 15" vac./51Kpa at idle.

2. Set mode switch in off position. Connect hand vacuum pump/tester to port #6 on pushbutton control vacuum switch, press mode switch to 'OFF' position. Block ports #1, #2, #5 and #7 on switch. There should be no leak. Pull the blockoff plugs from ports #1 and #2. Vacuum should flow through when applied to #6.

3. Push Auto-Lo or Auto-Hi button. Block ports #2 and #3 on the switch. Pump tester to apply vacuum. There should be no leak. Pull the blockoff plugs from ports #2 and #3. Vacuum should flow through from #6.

4. Push Bi-Level or DEFrost button. Plug ports #3 and #4 on switch. There should be no leak. Remove the plugs on #3 and #4. Vacuum should flow through from #6.






This part of an email sent to me from out in t.v. land:

He has replaced the compressor and put 134a in it and the compressor runs well, low side hose gets cold, but output air from ducts is very hot? Does it seem to switch modes when operating the pushbuttons and will blow from def. or bi-level vents but temp won't respond? I faxed wiring schematics. Suggest he listen at servo when switching temp key on engine off and see if there is any noise from servo as if motor is running. If not check all fuses, but since pushbutton and blower is working he either has a dead servo or a bad amplifier.Servo make no noise whatever when temp selector is switched. I suggested if he uses a fused jumper lead to pin 5 and ground pin 4 or vice-versa with the connector unplugged on servo, it should operate the servo motor and should affect in car temp. If no noise the servo is dead. If so likely amplifier may have been damaged also, replace.
He can drive the servo motor by applying power and ground and that moves it and changes the temperature, so likely has a bad amplifier not powering the servo.



Return email:

Tried the Servo first. It was bad. Then the AMP. It was bad. New parts and now it works as factory. Melted socket for the fuse. Had to replace.

 

Sorry I forgot one.

1. Check engine for any vacuum leaks. Check for vacuum supplied to port #6 of pushbutton vacuum switch on rear of control panel, green or green/yellow vacuum hose, with key on engine running (KOER). Minimum spec is 15" vac./51Kpa at idle.

2. Set mode switch in off position. Connect hand vacuum pump/tester to port #6 on pushbutton control vacuum switch, press mode switch to 'OFF' position. Block ports #1, #2, #5 and #7 on switch. There should be no leak. Pull the blockoff plugs from ports #1 and #2. Vacuum should flow through when applied to #6.

3. Push Auto-Lo or Auto-Hi button. Block ports #2 and #3 on the switch. Pump tester to apply vacuum. There should be no leak. Pull the blockoff plugs from ports #2 and #3. Vacuum should flow through from #6.

4. Push Bi-Level or DEFrost button. Plug ports #3 and #4 on switch. There should be no leak. Remove the plugs on #3 and #4. Vacuum should flow through from #6.

I will check as you mention here, but I thought I already proved the vacuum was integral enough to work, ie the flaps/vent are changing with the pushbutton as designed. Does this not more-or-less prove the vacuum system is nominal? Also, as mentioned earlier in my reply, When on bypass, the fan runs until I remove vacuum, then it shuts off (in bi-level). It restarts when I return vacuum. Note the schematic I supplied.. The voltage I am supplying is routed thru the #19 master switch. If there were no vacuum, the fan would not run, except on DEF (as voltage supplied via dual-contact relay#18).

... Does it seem to switch modes when operating the pushbuttons and will blow from def. or bi-level vents but temp won't respond? I faxed wiring schematics. Suggest he listen at servo when switching temp key on engine off and see if there is any noise from servo as if motor is running. If not check all fuses, but since pushbutton and blower is working he either has a dead servo or a bad amplifier.

Once again, servo runs, makes noises, verified visually it transits from hot to cool, and parks when ignition shuts off. Air goes from hot (def) to cool (when any other setting is chosen), so water valve is opening and closing. All this should be sufficient to prove servo is functioning.

I am suspecting, at this point, that the amp is dead/intermittent. Gonna remove it and inspect for poor solder joints, I think.

Now, the 50,000 question... Should the temp control work (servo function) with the fan bypassed as I have it (reference supplied schematic earlier). From my study of the schematics, I can see no reason why not. Reiterated, on DEF, the air is HOT!... blowing from def vents. When bi-level is chosen, the air moves from DEF to the FLOOR. As the air cools (because the servo transits from hot to park), the air moves from floor to center vents, regardless if the temp wheel is set at 85F or any other setting. ambient was 50F, engine was ~70C during tests... I even cooled the interior temp sensor with a blast of canned air (turned upside-down) and the servo did not respond. Obviously the AMP is not doing its job (or something in the sensor chain).

 

The owner of the vehicle I have been working on has an idea that may blossom into something... Gotta research a bit more, but, since his servo is "working", he asks, "...why not bypass the lower (water) end of the servo and install a manual water valve, al a early 107?" His idea has merit, but is not the answer, I think. I told him I just need some more time with the old gal. Perhaps after Thanksgiving...

I'm thinking a wire is broken somewhere and/or the amp is fubar, since there are more than one issue now to investigate (fan/blower control, and servo/sensor chain/amp issue).

 

I realize I have not updated this thread. Owner is satisfied right now, and life has gotten in the way of me spending any more time on it (new job/move pending, etc). I guess this chapter is closed without resolution. I am sure his amp is dead, and I think he has a wiring issue on the climate control panel... Alas, I guess I'll never see this one thru to fruition. I am hoping he finishes the project for his sake...

 

I fell there is a "The End" missing also.

 

Back on task with some measure of success. I removed bypass and placed everything back to factory... Some more sleuthing/checking, etc. Results are as follows:

In all cases, engine running and warm:

DEF
works... Servo drives to hot side of quadrant, fan runs, and warm air emanates from the def vents.
AUX water pump NOT running

BI-LEVEL
Blower does not run
"Think" I heard vacuum pods opening/closing
Servo responds to temp wheel, driving toward cool side of quadrant when set at 65F, to hot side when set to 85F
AUX water pump NOT running

AUTO-HIGH
Blower does not run
"Think" I heard vacuum pods opening/closing
Servo responds to temp wheel, driving toward cool side of quadrant when set at 65F, to hot side when set to 85F
AUX water pump NOT running

AUTO-LOW
Blower does not run
"Think" I heard vacuum pods opening/closing
Servo responds to temp wheel, driving toward cool side of quadrant when set at 65F, to hot side when set to 85F
AUX water pump NOT running

Shut car off, servo parks accordingly...

bypassed vacuum switch on bottom of the servo by connecting black/yellow at the tees...
Still no blower on anything but DEF. Also, never witnessed the AUX water pump running...

Q1:
Where the hell is switch #19 (master switch)? I find the switches on the metal header behind the glovebox, but they are NOT numbered as per manual. I think #14 on the car is #19 in the manual (switch body is green, green/orange vacuum hose, wiring colors also agree with manual, gn/ge).
Q2:
Where the hell is the Water pump temperature switch (#21 in the manual)? Would like to verify aux water pump operation.

Any Ideas?

 

Q1:
Where the hell is switch #19 (master switch)? I find the switches on the metal header behind the glovebox, but they are NOT numbered as per manual. I think #14 on the car is #19 in the manual (switch body is green, green/orange vacuum hose, wiring colors also agree with manual, gn/ge).
Q2:
Where the hell is the Water pump temperature switch (#21 in the manual)? Would like to verify aux water pump operation.

Any Ideas?

What color are the wires on it?

...

 

Picture of what you got going on?

 

Circled #19, master switch?

 

What color are the wires on it?

 

in the car, these items are numbered differently. the switch labelled #19 in the pic is labelled #14 in the car, and the wiring has a label on it as well.... #14. At least I think so... Sure can't find any other vacuum/electric switches behind the dash/glovebox. What a cluster f**k!

Can't understand the disagreement in numerology...

 

New Mystery #3...

What gets switched when auto-low is chosen on the push button controller? Nothing is on the terminals?

EDIT: Answered my own question... The fan is designed to be On as long as there is engine vacuum AND any selected climate function, ergo, no circuits needed for the first position? (this gleaned from the schematics of the climate control system and how the resistor pak interfaces with the fan controls, etc)

 

Case Closed...

Well I can close the book on the '78 450SL I have been helping rehab. If you have been following along, the last hurdle was the heating system (the owner will tackle the A/C at a later date...maybe. He states he doesn't car if it works or not).

What was the cause of the problem, you ask? VACUUM! In a nutshell, the vacuum system had been monkeyed with sometime in the past by the PO or else. After finally ferreting out that #19, master blower switch was in fact, labelled #14 in the car, the starting point was simple. Closing this switch resulted in the blower working perfectly. Now it was down to why no/not enough vacuum to close the switch? Well... looking for a leak/leaks is a time-consuming and tedious process. I got lucky, and the leaks were few, the major one being a broken plastic line. I blew cigarette smoke into the main line from the servo thru the dash and VIOLA! My buddy was able to find the smoke. We repaired the line and tested. All systems nominal!

The rest of the day was spent removing a BS alarm system that had been hanging (literally) around, and buttoning up all panels. We added a cigarette lighter (constant hot) to the glove box for cell phone/whatever, and fixed a few misc electrical gremlins (the glove box light, et al). Last thing was to install a dash cap to cover the few cracks in his dash (we found a brown one in excellent shape in a wreck at the boneyard, which matched his interior).

ACC II is not all that bad when you get down to it. Pretty ingenious, really. The key, of course, is having a working servo to start with (looks new). The amazing fact is none of his pods are leaking...yet.

The old gal is ready to cruise... I can't name all the things we have done to the old car, but I am proud to have been associated with the rehab. Another 107 saved for future enjoyment!

RMS Out!

PS One last thing... The vacuum system has to be tight for the aux heater pump to run. Also, on the '78, the pump will run until the water temp gets to 75C, then will turn off until the water cools down to 69C in the heater core water circuit.

 

Well I can close the book on the '78 450SL I have been helping rehab. If you have been following along, the last hurdle was the heating system (the owner will tackle the A/C at a later date...maybe. He states he doesn't car if it works or not).

What was the cause of the problem, you ask? VACUUM! In a nutshell, the vacuum system had been monkeyed with sometime in the past by the PO or else. After finally ferreting out that #19, master blower switch was in fact, labelled #14 in the car, the starting point was simple. Closing this switch resulted in the blower working perfectly. Now it was down to why no/not enough vacuum to close the switch? Well... looking for a leak/leaks is a time-consuming and tedious process. I got lucky, and the leaks were few, the major one being a broken plastic line. I blew cigarette smoke into the main line from the servo thru the dash and VIOLA! My buddy was able to find the smoke. We repaired the line and tested. All systems nominal!

The rest of the day was spent removing a BS alarm system that had been hanging (literally) around, and buttoning up all panels. We added a cigarette lighter (constant hot) to the glove box for cell phone/whatever, and fixed a few misc electrical gremlins (the glove box light, et al). Last thing was to install a dash cap to cover the few cracks in his dash (we found a brown one in excellent shape in a wreck at the boneyard, which matched his interior).

ACC II is not all that bad when you get down to it. Pretty ingenious, really. The key, of course, is having a working servo to start with (looks new). The amazing fact is none of his pods are leaking...yet.

The old gal is ready to cruise... I can't name all the things we have done to the old car, but I am proud to have been associated with the rehab. Another 107 saved for future enjoyment!

RMS Out!

Good thing you had a Cigarette, after she got done screwing you.


Sorry I wasn't any help, but Im in the middle of tearing down this 107.

 

:thumbsup::thumbsup: Nice thread. Possibly belongs in the EGv107. Nothing in there about the ACCII.

 

Added 03/01/2012

 

Final Chapter...

My friend took his 450 in to have the AC evaluated (7 years his ownership, bought in a non-functioning state). Tech drew a vacuum, and surprisingly, it held (at least long enough for him to assume it was sealed enough to risk a charge). Charged it up with R12* (and lubricant), and damned if it didn't work! Functions as per design, modulating the temp when set/adjusted. Compressor sounds fine, with no abnormal noises...

Who knows for how long. Makes me realize how robust these older cars were built.

Peace, Out!

*Edit: R134... The tech "converted" it...