Climate control programmer question

[2seater]

I think I remember a thread some time ago about the internal workings of the programmer but a search didn't turn up what I am looking for. The FSM doesn't really list any definitive tests for the internal workings. Specifically the operation of the solenoids for the vacuum actuators. Any insight?

[Guest Mc_Reatta]

If the only place the air comes out is the defrost vents then the problem is most likely the vacuum supply line.

The symptom that a solenoid isn't working is one vent won't activate while the others will, and it's not a vacuum leak or disconnected hose. I had my AC vent solenoid burn out so no air would come out the dash vents but would come out the upper defrost vents and the lower heater vents as commanded. Replacing HVAC controller solved the problem. Each solenoid could be replaced separately inside the controller (they are all the same) If you have spares. I kept the bad controller so that I can do this if another fails. To test the valve itself, you could use a vacuum tool like a Mighty-Mite to pull a vacuum on the hose going to that valve (color code chart is in the FSM) to see if the air will then come out of that vent. If it still won't, then problem is with that line or valve, not the solenoid.

Sometimes the valves can stick if not used very frequently (like the heater vents in FL) and cycling thru the delivery options many times might free them up some so they will work again. They are very hard to get, at being buried behind the dash, so lubricating them directly is a pretty difficult proposition.

[2seater]

Thanks for the info. It sounds like you have covered the ground before. All actuators do work, hold vacuum and will switch the operations with a hand pump as suggested. Applying vacuum to the inlet of the each of the solenoids inside the controller shows two hold vacuum and two do not (yellow and red). I have a used replacement programmer that also has two solenoids that do not hold vacuum, (yellow and blue). Neither programmer operates the air direction properly. Both programmers do control the fan speed fine and also the temperature control door. I am pretty sure they should hold vacuum unless activated, but the FSM is mute on the subject. Supplied vacuum to the programmer was over 20". Cannot pump up the programmer with a hand pump as leakage through the solenoids is too bad. They appear to leak out the filter in the rear, not through to the actuators. Solenoids all show about the same (mid 70 ohm) resistance across the top terminals but that may be invalid since they are still connected to the circuit board. The CRT display changes appropriately so it would seem the feedback circuits work correctly?

Is there a source for the solenoids? I might try replacing the suspect ones rather than running through a bunch of used programmers without a reasonable hope of success.

[Guest Mc_Reatta]

I take it the problem is not in the internal vacuum lines running from the connector up to each solenoid.

What exactly are your symptoms?

I don't think the solenoids are meant to hold vacuum on the side connecting to the output lines when unenergized, but should hold vacuum on the supply side. This allows the valve to close off the vent so air is directed to the open one. The defrost valve is reversed (normally open), in that with no vacuum it is open and allows air to pass. When air is requested, a vacuum is applied to it, and the needed vent valve (normally closed). This closes the defrost vent, and opens the requested vent.

If I understand you correctly, you can't pull a vacuum on the supply side when nothing is energized which I believe is a problem. Only place I know to get another solenoid is from a donor controller. If you have a second one swap out the ones that won't hold a vacuum on the supply side and that measure 70 ohms or so across the coil.

I've only have one solenoid fail in one controller so I think these controllers are pretty failure free.

[2seater]

That is what has me somewhat confused. Two solenoids in each programmer do hold vacuum on the supply side, but one is different from the other. Both do not hold on the yellow, which is supposed to be the upper so I will check to see if it routes vacuum through to the actuator side which would make sense as the default is defrost. It is still a bit curious as the neutral position for the upper lower actuator is in the middle, or split flow. All coils in both programmers do have continuity, but the curious thing is all coils in the replacement unit are centered around 76-77 ohms, and the original center around 73.5 except the yellow which is 77.5. Another curiosity is checking voltage across the coils while switching functions in the CRT. All coils at some point show 10.0-10.1 volts except the red (lower) coil in the replacement programmer which always reads zero. I would think it certainly show voltage when in the heater position but I would guess there may be bad communication with BCM or, there is a fault in the board. Should I be able to operate the solenoid by applying voltage across the coils, or would that be hazardous to the circuitry?

[Guest Mc_Reatta]

Do the colors of the vacuum lines inside of each controller correspond to each other and to the color of the external lines? I remember the spare controller I replaced my original one with had different colored lines from the original. Not sure if someone had messed with it, or factory didn't follow the same color code for the lines. This made things more confusing than they needed to be.

Don't think the small differences in resistance you are seeing between the coils is significant.

Is the one solenoid that you never see getting voltage the one going to the orange external line? This would make sense since it is controlling the valve that controls outside air and cabin recirculate modes. It will only be energized if the controller is set to MAX Cool and does not respond to AC, Def, Heat or Bi Level air delivery switches. If it is the one controlling the red line then you should not be able to get air to come only out of the floor vents.

What is your symptom that has you looking at this? Hard to help you troubleshoot a specific problem when I don't know what it is.

[2seater]

This is an '89 I am attempting to rescue. The air delivery had the typical air out the defrost only with some flow from the floor vents. I went through the diagnostic tree in the FSM, checked the operation of the actuators and vacuum supply. The conclusion was the programmer was defective. I received a replacement used programmer, connected it and no change in operation. I looked at the replacement in some depth and noted the vacuum connections are in a completely different order. I opened the cardboard cover and noted the red solenoid is in a different location on the circuit board. I moved the internal hoses around on the outlet connector to match the colors for the actuators. Still no joy on the operation. The only thing I have not done yet is compare the electrical connections in detail. At first blush the color codes appear the same although the 12v ign. wire is a different color. I then started the detailed look at the solenoid continuity, vacuum holding of the solenoids etc... I suspect the original programmer is defective and the replacement is also defective, or, is an incorrect match.

The solenoid with no voltage in the replacement is the red one, or at least it has a red stripe hose connected to it internally. It is also the solenoid that is in a different location than the original.

Edited May 22, 2014 by 2seater (see edit history)

[DAVES89]

I think you should meet me at Gibson's and get one there. There has to be 4-5 out there...

I just remembered I have one also here. Swapped it out of the Black. It may be no good but it is yours if you want it.

[2seater]

Thanks Dave, that is one of my alternatives and I may take you up on the takeout. Was it defective?

Right now I am attempting to understand how the programmer gets it's information and what it should be doing with it. Does anyone know what tells the programmer what is desired? I know the BCM has many different modes but am curious how that information gets to the programmer? I checked the data line from the BCM to programmer, tan wire in the "T" cavity but that is teed with several others. It shows a pulsing voltage under five volts and a frequency around 1kHz but does not change with a change in requested operation in the CRT, at least not a definitive change. The frequency changes between about .8 and 1.2 kHz fairly rapidly. Now that I think about it, I had the door open and the activation of the courtesy lights causes a pulsing voltage on that line also, with the ignition off, perhaps confusing my result? Any insight?

[Guest Mc_Reatta]

You are correct in that the BCM talks to the HVAC Controller over the E&C Data Bus. You need more than a frequency counter to see the subtle differences between the commands. The Controller interprets the commands and sends the proper command voltages to get the desired effects. The blower speed control is not part of this process, it's separate.

I'm pretty sure your major issue is that all of the solenoids cannot hold vacuum when at rest on the supply side. They are bleeding off the vacuum so it can't close the defrost flap and allow the air to get to the upper lower distribution box. There is probably another issue with the one Controller that has no voltage on the red circuit, but that would be a secondary issue.

If I remember correctly, Daves89 changed his HVAC controller because he had an issue with it, so if that's the one he has in stock, recommend you go to Gibson's with him and get your own. Bring your Might-Mite with you and find one that will hold vacuum on the supply side, and check the resistance of the coils so you get one that has the best potential to work when you get it home.

Just retrieved the one I replaced because it wouldn't switch to AC mode, and now none of the valves will hold a vacuum on either side, and all coils were measuring 77 ohms. All 4 of my valves look identical. The only ID on the module which I believe to be OEM from my 89 is a bar code sticker with 384466 on it.

I expect the root problem is they won't hold a vacuum at rest.

But reviewing this module gave me an idea on how to solve one of my pet peeves with the Reatta in that the only way to enter recycle mode is to be in MAX Cool. If one were to attach a wire to the + side of the coil that controls the outside air flap (the black vacuum line), and attach it to a switch that would provide 12 volts, you should be able to enter recycle mode by bypassing the BCM. And here I was waiting for someone to figure out how to reprogram the BCM. Just need to verify that recycle mode is enter when coil is activated not the opposite.

[2seater]

I will admit I am using the diagrams from a '90 FSM for diagnosing the '89 but I am pretty certain the actual moving parts are the same. Looking at the air door diagram, the defrost-a/c outlet is simply defaulted to the defrost position and it requires vacuum to the actuator to close it off for air to the dash outlets. The actual vacuum solenoid is the same as the other three, not reversed.

I agree the subtle communication nuances are beyond my ability to measure. I just know there is something there and I only question it because of the sad shape some of the rest of the car is in. It looks like the FSM assumes the communication is correct if the display changes properly. More after the weekend. It will have to sit and wait.

[2seater]

As near as I can tell, you only need ground the pin on the right as viewed from end toward electrical and vacuum connections. It appears the solenoids have power at all times the ignition is on, sort of like the injectors which are always hot with a switched ground. I still need to verify but all solenoids will click with power on the ign+ connection and tap the ground on that pin. Draw is about .6 amp. Sorta curious why recycle air without a/c? According to the diagram there is always about 20% outside air when in recycle. It also has a delay built in, listed as a porous plug.

Nope, I was wrong. Apply vacuum to the solenoid inlet, click the solenoid and nothing happens. I tried it on one that holds vacuum and the red one which leaked down. Nothing comes through on either one. One maybe good thing with all the trying different things is the red solenoid now holds pretty good vacuum although not perfect. Click or no click, the vacuum on the inlet doesn't change. I must be thinking about them incorrectly but I don't know what it is at this point. They are a simple mechanism. Energize the coil and the pintle inside retracts, opening the passage. It must also close the vent passage that relieves the actuator when powered down.

Edited May 27, 2014 by 2seater (see edit history)

[Guest Mc_Reatta]

Sorta curious why recycle air without a/c?

Hard to get good performance when ambient is either below zero or in the three digits.

According to the diagram there is always about 20% outside air when in recycle. It also has a delay built in, listed as a porous plug.

Keeps CO poisoning risk low.

I believe your thinking is correct. Sounds like the rubber seals that are activated by the pintle have hardened and are no longer functioning properly.

This may be bad news for us to be able to acquire these controllers from P&Ps. RockAuto shows it available new, but the last cars to use them were the 93 Riviera and Allante.

[2seater]

I don't know what to think. The red solenoid got better at holding vacuum, so my original controller only has one that does not. The venting of the actuator side is open on all of them, but doesn't close when activated. It may indeed be a seal problem, but it acts more like the pintle doesn't travel far enough. It seems a shame to discard an otherwise good unit. I don't want to destroy something that may be salvageable but perhaps a dissection of a solenoid may be necessary.

[Guest Mc_Reatta]

Possibly could be pintle is sticking, might try cleaning and lubing one to see what happens. If it works electrically and holds a vacuum, there's hope.

[2seater]

I must admit I am a bit stumped right now and it's also painfully obvious that I know very little about how it is supposed to operate, or, it doesn't operate properly. I powered the circuit board as it would be in the car. Ign. and ground (K). Interestingly, all four solenoids have voltage across the coil and they all click when the board is powered up. When this happens, the yellow solenoid now passes vacuum to the actuator hose and releases when power is removed. It does not hold vacuum at the inlet when unpowered. The three solenoids that hold vacuum unpowered, still hold vacuum but do not pass the vacuum to the actuator port like the yellow one when the board is powered. I had thought about external solenoids powered from the board, but the operation is apparently much more complex than I imagined.

[2seater]

I finally bypassed the internal solenoids with four new ones mounted to the outside of the box. It works just fine now. All functions switch around as they should. It isn't pretty but the solenoids appear much more robust than the originals.

[Ronnie]

I finally bypassed the internal solenoids with four new ones mounted to the outside of the box. It works just fine now. All functions switch around as they should. It isn't pretty but the solenoids appear much more robust than the originals.

Good work! We need more thinking outside the box like that to come up with new ways of extending the life of the Buick Reattas.

[Guest Mc_Reatta]

I agree! This is a powerful first step forward that will become increasingly more important as age takes its toll on these 25 year old valves. While the ones in the cruise servos seem to fail much more frequently, I think this is due to the fact that they live in the hotter engine compartment vs the passenger compartment. Just a matter of time before these HVAC ones catch up.

Hard to tell from the photos if a good shoe horn couldn't get them to fit "inside the box".(pun intended)

[Machiner 55]

Outstanding!

Where did the new solenoids come from?

John F.

[2seater]

The valves could likely be located inside the box after removing the original ones, however, the case is metal and conductive so isolation from the circuit board would be needed. I simply nipped the wiring from the existing coil to the connection and soldered the new ones on. I was going to remote mount them and fab. a connecting cable but I found there was adequate room to mount them on the rear and the box itself can be installed and removed with them in place. The spaghetti looking wiring is the result of the length of the supplied wiring on the solenoids. They could be extended and make it a bit neater, but I found it looks fine once the paper cover is installed

These are the valves:

http://www.ebay.com/itm/2-phase-3-channel-mini-Solenoid-Valve-Discharge-Ventilation-Valve-6V-12V/231026023759?_trksid=p2045573.c100033.m2042&_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D22872%26meid%3D7429476984474026221%26pid%3D100033%26prg%3D9836%26rk%3D1%26rkt%3D4%26sd%3D231026023759

There are name brand valves also available at two-three times the cost. Too rich for an experiment.

[buickguy62]

Great piece of work--thanks!!!

[2seater]

Upon reflection I wish I had added LED indicator lights across the terminals just to be able to watch what is going on. Could still do so I suppose? A couple other observations while testing the circuit board on the bench. If only the programmer signal ground "K" is connected when powered, all solenoids are powered and have voltage across the terminals. When the second ground "L" is connected (as it would be when installed) the voltage at the solenoids disappears. My uneducated guess is the ground is switched to activate solenoids? The second thing is, the yellow solenoid (upper air) is switched "on" when the ignition is switched on. This would be maximum air to the defrost.

[2seater]

Another resurrected thread to answer a question from Mc_Reatta regarding overriding a solenoid manually. The circuit to the coils is the saturated type, similar to the fuel injectors. Constant twelve volts and a switched ground to activate. To override, simply ground the right side terminal, as viewed from the vacuum hose end. The other alternative would be a three way toggle valve to select straight manifold vacuum or the programmer vacuum to the recirculate diaphragm. This could be done without having to remove the programmer but you would have to add a couple of tees to the vacuum feed and operator tubes under the dash.

[Guest Mc_Reatta]

Thanks for the update. This info will make it easy enough to take one of my items off the wish it could list.

[millerrepairllc]

On ‎6‎/‎20‎/‎2014 at 5:05 PM, 2seater said:

I finally bypassed the internal solenoids with four new ones mounted to the outside of the box. It works just fine now. All functions switch around as they should. It isn't pretty but the solenoids appear much more robust than the originals.

BRANDON MILLER FROM MILLER REPAIR LLC COLDWATER MI. where could I find these solenoids for our customers car a 1985 buick grand national? please and thank you

[2seater]

This is similar to the valves I used, but are quite a bit more expensive. I found these on ebay, where I got the first ones from. You are looking for micro solenoid valves, 12v, and they must exhaust when unpowered, so three ports total. I will help if I can.

https://www.amazon.com/Fincos-DS-0520ST-Position-Solenoid-discouraged/dp/B07RTMLQN9/ref=sr_1_10?keywords=12v+micro+solenoid+valve&qid=1566313474&s=gateway&sr=8-10

[millerrepairllc]

On ‎8‎/‎20‎/‎2019 at 11:11 AM, 2seater said:

This is similar to the valves I used, but are quite a bit more expensive. I found these on ebay, where I got the first ones from. You are looking for micro solenoid valves, 12v, and they must exhaust when unpowered, so three ports total. I will help if I can.

https://www.amazon.com/Fincos-DS-0520ST-Position-Solenoid-discouraged/dp/B07RTMLQN9/ref=sr_1_10?keywords=12v+micro+solenoid+valve&qid=1566313474&s=gateway&sr=8-10

THANK YOU for your help we greatly appreciate it!