I have a '66 Toro. I've had good luck using a mechanical vacuum regulator to force the Power Servo to give me whatever setting I want (Full heat is high vacuum, full A/C is no vacuum, with many in-between options). Since the power servo controls the mode door, blend door and fan speed, it works quite nicely.

https://www.mcmaster.com/41585K43/

For those pulling their hair because of non-functioning confortrons, this is a very easy way to make it do whatever you want manually.

 

Thank you for that information. That's the servo motor under the hood right? Does that mean if I cap off the vacuum to the servo I will get cooler air coming in? Right now it seems to be stuck on heated air, which comes in even when I turn the switch to "off"

 

Get a cheap hand vacuum pump and apply a varying range of vacuum to the diaphragm of the Master Servo. If the rest of the system is more or less intact, it will cycle from "Full A/C to Full Heat" as you go from 0 to 15in Hg. The long arm coming out of the Power Servo is moves the blend door (hot/cold). You should see it move as you vary vacuum to the Power Servo.

 

Would anyone have a pic of one of those valves installed?

 

What valve? The vacuum pump?

 

So with no vacuum to the servo it should be on full AC? (Or outside air temp if no Freon)? Which vacuum line do you do this to, I see one large one and a few smaller lines coming from the heater valve?
Also, should I be able to move the blend lever By hand back and forth the car shut off?

 

No that aftermarket valve that was referenced above

 

 

Got it, thank you
now maybe I won't have heat blowing on my feet for the rest of the summer 😎
If I pull the vac from the servo and it goes to ac will it blow thru the vents and not on the floor?

 

Yes, try unplugging it and let us know what happened.

 

One more thing, do I have to plug the rubber vac line that I pulled out of the servo, or do I plug the servo motor itself?

 

I would plug it.

[ QUOTE=sgolds;1366262]One more thing, do I have to plug the rubber vac line that I pulled out of the servo, or do I plug the servo motor itself?[/QUOTE]

 

Any luck?

 

Pulling It did stop the heat from coming out, just in time for the weather to cool off haha

do I have to cap off both the servo and the vac line?

 

I am working with both my mechanic and Dr Kennedy to diagnose the Comfortron on my 66 Toronado. Blows full hot only. Is there a specific service manual for the system and has any got access to a scan of it? Or is it part of the overall service manual for this car? I have printed the yellow “simplified” manual available here - thanks, that’s an excellent start!

 

I'm a big fan of "divide and conquer". This system is made up of several sub-systems that work together and one of them failing can make it look like the problem is elsewhere, sending the repairer on a wild goose chase. I like to send a variable vacuum signal to the power servo and verify that the system operates from full cold to full heat. Then other parts of the system can be tested separately.

 

For 68, there is a section in the chassis service manual. I would think 66 has the section as well, but there is also a supplemental service manual for the A/C system which covers comfortron and regular systems:
https://www.ebay.com/itm/39228312349...0AAOSw2GlXKUh4

 

if I put vacuum to the servo and i get heat, and it blows cool air when I remove and cap the vacuum line, does that mean the servo is working correctly?

 

Yes

 

OK, got a vacuum pump to test vacuum levels, can I pump the underhood servo unit when the car is off, or will I just see a reaction when its running? Im looking for the lever on top of the firewall to move Im assuming.
In the meantime, the heat stopped working completely and now it just blows cold air, regardless of whether the vac line is on the servo or not
Maybe it will start heating again next summer

 

Without the engine running, the power servo will lose some of its functionality, assuming it you actuate it manually.

 

If the engine is not running, if I pump vacuum into the servo should I see the arm that's attached to the servo start moving?

 

Yes. If the system is energized (you can actuate the master switch) you should hear the fan change speeds as vacuum varies.

 

I pumped the vacuum pump into the under hood servo unit but nothing happened. This is with the car not running and the key turned on. I get no fan at all. The Low setting does not work no matter what, but the Hi setting sometimes works with the car running.

Also, Should I be seeing a vacuum reading on the gauge?

 

Did you jump or actuate the master switch?

 

Just turned on the fan switch, is that what's meant by master switch?

 

The master switch powers the system when there is engine vacuum. It typically sits on the A/C evaporator box. It has (depending on the year) four vacuum lines and two wires going to it. If you squeeze it from behind you can actuate it.

 

You'll also need to jumper the coolant temperature switch on the heater water valve. Coolant temperature has to be >120° for Comfortron to operate in automatic LO or HI. You can force it to operate by switching to DE-ICE which bypasses the temp switch but also switches the outlets to the defroster. That may or may not give you a good test condition.

Contacts in the blower speed range switch may be crudded up after 55 years too.

Marvelous piece of engineering but a lot to go wrong, especially in an automotive environment.

 

So I have to unbolt it from the firewall and then squeeze the back to activate, and I should hear the fan come on? Sounds like a 2 person job, 1 to do that and the other to put vacuum into the servo?

 

Crazy complicated!😖

When I put it on De ice with the key on I get nothing. I should do the above mentioned with the master switch with it on De-ice?

 

You should be able to reach the rear of the switch with your fingers and squeeze without removing it. There is a diaphragm in the rear of the unit, which actuates a switch. You can put something in there to keep it actuated while you test the system, if you need.

 

Ok, I pushed the back of the master switch and the fan came on. seems that the more vacuum I put into the servo the slower the fan got, and I could see the arm start moving

 

Where is the coolant temp switch? All i see on the water valve is a few vac lines and the heater hoses

 

OK, forgot 66 uses a vacuum water temp switch. Was thinking it was electric like later ones.

Do you have a hand vacuum pump? Harbor Freight or most chain parts stores have them and they're handy for work like this. Mityvac is a well known brand but HF Pittsburgh will do the job.

 

Yes I do have a vac pump got it from harbor freight

 

So that's working properly. If the fan works intermittently, you can check the master switch. If you have a vacuum leak somewhere, the master switch may not have enough vacuum to actuate.

You can change the temperature setting in the control panel and see if that has an effect on vacuum going to the Power Servo. You can put a vacuum gauge on that line, or watch for movement in the power servo.

 

I can do that with just the key turned on, or does it have to be running?

 

Running. Otherwise there will be no vacuum.

 

Ok took the car out today, no fan on low or high, even when I activated the solenoid on the back of the master switch. I just got a loud solenoid click at the switch. When the car was running the switch was pulled into the On position.

I am working on removing the blower resistor, but I plugged it back in before driving. Would the high speed position still work if the resistor is bad?

 

Check that these components have power (in this order)
- Master switch
- Power servo
- Range relay (on passenger side inner fender)
- Fan