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rfisher 01-09-2021 09:44 AM

another revisitation on old actuator trick
hi sages- moe said in the war better learn more than one way to skin a cat to stay alive. still wrestling with finding a replacement mode actuator . many sources including gm who has abandoned saturns support have dried up . contacted 2040-parts .com who listed having a nos actuator but they wouldnt respond to my efforts to order. in this war thought of an alternate catskinner. the actuator will sound and then stops and stays on dash vents. heat ac and vent work, but i need the defrost position for safety on the dark and damp tobacco road. figure circuit board in unit must be clusterf!@#ed. since each of the hundreds of actuators available have this circuit board(ford, chev , dorman etc. etc) but each one is different maybe the answer is fixing board in my unit. has anybody here fixed this board or know of a source who could. electronics and computer intrigue are not in my toolbox. gm supermechanics even with many certificates on office lobby walls dont know jack . anybody here know jack . ?need clear and defrostable windshield to evade coppas on thunder road . thanks tons bob f

02 LW300 01-09-2021 05:50 PM

Re: another revisitation on old actuator trick
There is a cam setup on the flappers, my car gets stuck a little between floor and defrost this winter. So my question is does your car switch from floor to both to dash ok? I am going to tear my car apart and lube the cam for the defrost and see if it helps. This might be all you need to do for your car also. I have a couple complete heater boxes out if you really need an actuator.

02 LW300 01-09-2021 08:38 PM

Re: another revisitation on old actuator trick
5 Attachment(s)
Here are some pictures of a hvac unit I have out. The picture of the flappers show the larger center one which is center, the two on the sides are defrost. There is also a picture of the floor arm. The motor turns the cam and the three arms run in slots on the cam to open and close the various flaps. I suspect that my car is as dirty as the one pictured. Some aerosol cleaner and lube should restore proper operation. This can be viewed by removing the glove box assembly and maybe the passenger seat for easier access.

rfisher 01-09-2021 09:18 PM

Re: another revisitation on old actuator trick
hi lw- never saw those pictures of the flappers. i am going to take out the glove box and see what i can see. those pictures wil help. my car has the manual hvac system , not the automatic climate control. mechanic told me that the mode actuator had failed(not the recirc actuator). will try to blow it out as much as i can and then lube the flapper mounts if that is binding. mechanic tried to get an actuator and couldnt find one . this led me to an unsuccessful search for one. i may very well be in touch with you if you have a mode actuator. do you in fact have ones that work? right now heat, ac and vent air
come out the from dash vents when the blower motor is on . that function can be regulated, but other air directions cant. mechanic told me he manually turned the cam plate so i could get air from the front vents. if i turn the mode wheel on dash to defrost i get no air as if the vents are closed. thanks tons i appreciate your help. bob f

02 LW300 01-09-2021 09:32 PM

Re: another revisitation on old actuator trick
I have several units out so I can test one and let you know. So you have no movement of air flow just temperature adjusts? Sounds like everything comes out the dash vents. The floor vents suck on these cars but the defrost works great when it gets there. I use defrost and blend in the winter and dash vents the rest of the year.

fdryer 01-09-2021 09:44 PM

Re: another revisitation on old actuator trick
02 LW300, according to my '03 service manuals, the mode control actuator controlling the door position for defrost/face vent/heater (floor), is a four wire unit. Two wires for the feedback position sensor and two for power to the motor. If I can presume the L-series share the same actuators, perhaps repairs are possible.

Testing actuators out of the hvac box depends on whether or not the wiring harness is long enough to command the actuator into one or all three positions. The feedback position sensor operate on a 5v circuit. The wiring diagram doesn't show operating voltage to the motor other than stating SOLID STATE. This may mean a digital pulse from the hvac control head to power the motor. I don't know unless I have to troubleshoot mine. In theory, the only two failure modes of actuators are either the motor or position sensor. If a broken or intermittent connection is found anywhere within the actuator, this can be easily repaired.

My L300 blew its solid state resistor card a few years ago. I don't remember where I bought the replacement but it solved the blower speed problem. The finned aluminum box acts as a heat sink for the power transistor and a few components, one of them a thermal fuse or fusible link. On a hunch, I cut one connection and measured an open across it. It blew. Specs are silk screened on it if I ever get around to replacing it for a spare. I don't remember if I made cursory measurements on the replacement for comparison purposes but the original shows no visible signs of heat damage or bulging components. The fusible link is a standard part available from electronic distributors.

If anyone is willing to send me their damaged but intact actuator, I may be able to disassemble it for show and tell. And determine if it can be repaired. There may be actuator motors from other GM actuators, gears if any, and feedback position sensors for swapping. The only way to know is by disassembling one then determine what failed. This is by no means the only solution as service manual diagnosing procedures use flow charts to systematically troubleshoot wiring, and actuator using a simple test light to determine if the hvac control head is faulty, wiring damage or actuator fault. No mention of binding mode/temperature doors but that is another possibility.

rfisher 01-12-2021 09:21 AM

Re: another revisitation on old actuator trick
hi lw- need my defrost position to work on the rotary wheel . do you have a mode actuator spare that works and you would sell? mine may have failed due to mysterious crapout on the resistor sensor card. seems no one left in america who can repair that item and inventory is depleted. wondering if a push pull cable could be reverse engineered to actuate the defrost air direction. even thinking of mounting a semi truck dash fan on the dash top to blow air on the windshield when fogged. my enemies will then think the L is a true bohemianmobile. i say to hell with these impossible to fix or acquire actuators, interference engines and hydraulic clutch release bearings. bet you think my attitude is the worst. thanks tons bob f

02 LW300 01-12-2021 10:42 AM

Re: another revisitation on old actuator trick
I will look this weekend, and yes you could move all the flaps with three cables. You can have dash only, floor only or defrost only plus any combination of above.

rfisher 01-13-2021 08:59 PM

Re: another revisitation on old actuator trick
hi lw- thanks will look forward to what you find. bob f

rfisher 01-14-2021 10:26 AM

Re: another revisitation on old actuator trick
hi lw- actually only interested in two functions : 1. front dash vents which now is open and ac and heat work well. 2. most interested with getting the defrost to operate(looks like curtains on replacing the mode actuator) . may want to cable in the defrost door and run the push pull cable downunder the glove box and mount to side plastic bolster or to the metal frame under the box. what think? my only concern is whether actuating the cable on the defrost door will cause a clusterf@#!k on the operation of the front vents. what think #2? appreciate your sage advice . still hoping on your working spare mode actuator which would be the easy way out. regards bob f

02 LW300 01-17-2021 05:31 PM

Re: another revisitation on old actuator trick
2 Attachment(s)
I tested this mode actuator in my parts car just now and it works perfectly. I ran the fan and felt the air move as directed. I removed the actuator and observed it move as commanded. I am going to test a couple more while the jumper cables are connected to the parts car.

02 LW300 01-17-2021 06:02 PM

Re: another revisitation on old actuator trick
1 Attachment(s)
I have tested and I have three good mode actuators. I will sell you one if you PM me.

02 LW300 01-17-2021 06:09 PM

Re: another revisitation on old actuator trick
1 Attachment(s)
Another picture.

Jim@HiTek 01-18-2021 12:52 AM

Re: another revisitation on old actuator trick
[QUOTE=02 LW300;2356097]I have tested and I have three good mode actuators. I will sell you one if you PM me.[/QUOTE]

Would this actuator be the same one used in a '03 L200?

My symptom seems to be that setting the heater for defrost doesn't seem to do anything, there's no air there. It all comes out the dash vents.

That's weird of course because for decades there was a federal automotive law that said any failure of the heating system must default to defrost. Never read if they'd rescinded that law or not.

pierrot 01-18-2021 02:15 AM

Re: another revisitation on old actuator trick
[QUOTE=Jim@HiTek;2356105]Would this actuator be the same one used in a '03 L200?[/QUOTE][FONT="Palatino Linotype"][SIZE="3"]Yes, it is. The OE p/n 2273265[U]3[/U] is used for [B][U][COLOR="DarkRed"]all[/COLOR][/U][/B] L-Series cars which have the [COLOR="Blud"][U]manual[/U][/COLOR] HVAC controls. The same is true for the air inlet actuator, OE p/n 2273265[U]2[/U]. So whether it's a sedan or wagon, regardless of engine size, these are the only actuators ever used in their manual HVAC system for six model years, '00 to'05.

(I know, I've been redundant here, but it's not may fault. It's a genetic problem I have and I know that it's true because Martin Mull demonstrated it on an important documentary called, "A History of White People in America." [I]Nobody would lie about a thing like that...would they?[/I] :xeye::tounge:;))[/SIZE][/FONT].

rfisher 01-18-2021 09:02 AM

Re: another revisitation on old actuator trick
hi jim hitek and pierrot- never heard of that law about mandatory default to defrost nor saw an electronically activated hvac that did that. actually a very good safety thing. would be a very important at 100mph on a dark and cold desert highway(tobacco road) evading coppas . curious question pierrot, what about the ion which i think was the successor to the L series. did both share the same hvac and actuators? thanks tons bob f

fdryer 01-18-2021 12:09 PM

Re: another revisitation on old actuator trick
[QUOTE=Jim@HiTek;2356105] ....That's weird of course because for decades there was a federal automotive law that said any failure of the heating system must default to defrost. Never read if they'd rescinded that law or not.[/QUOTE]
Whether this was hearsay or fact, a problem remains if this were true.

Most here can remember the old days of manual ac and heater controls with levers or dials connected to mechanical linkages. These mechanical controls adjusted the temperature and mode doors. The temperature door simply moved airflow to allow more or less heat from the heater core to regulate heat when needed. The mode door selected defrost, face vents, floor vents or face and floor vents. Presuming linkages aren't damaged or modified, they tend to lsat the life of most vehicles. I don't recall any federal mandate for these hvac controls to default to a specific position if they fail since they're mechanical and tend to remain in the last selected position. Based on this mechanical configurations, stepping into automated climate control systems with a mini computer to power actuators for the same temperature and mode doors, once power fails these actuators remain in the last position. No memory from module to command them to a default position.

Jim@HiTek 01-18-2021 01:00 PM

Re: another revisitation on old actuator trick
[QUOTE=fdryer;2356115]Whether this was hearsay or fact, a problem remains if this were true.


I don't know where you young whippersnappers spent your youth, but yes, there was a 'rule' (not law) that automotive 'mechanical' comfort systems had to default to 'Defrost'. That's still true in my '02 Winnebago RV. And was true in my '94 Bounder, and most of the older cars that I owned. Many of us older folks remember that from our younger days in our old clunker mobiles. If our heaters died, we still had defrost.

It's a trivial mechanical design to have the system set for defrost at all times, and have the actuators for other heat/cool sources (dash, floor) active as required. So when the car was running, the air doors would be held in position for other areas. If the power to the system failed, they would return to home position, redirecting air from a fresh air vent to the windows. So 'defrost' would basically be passive and all the other acutators would be actively supplied as called for by the controls.

As far as an electronic design, since that's what I did for a living for many decades, I'd think a design that defaulted to 'Defrost' in a modern electronically controlled system would be trivial as well. Since the system uses 'doors' to redirect air flow, and springs are still a thing.

But in my '03 L200, I'm not seeing that. What I'm seeing is defrost vents totally devoid of any air flow. I put a piece of paper on the dash over a vent opening and drove around this AM in 48 F temps and never saw any movement of the paper for any settings of the electronic controls. I tried everything.

So I guess that rule either was dropped OR there's sensors in the car that know defrost wasn't needed and so kept it off? And I'm in the desert so defrost really isn't needed. I just find it strange I can never get air out of the defrost vents.


[Oh, wait...should I start a new thread?]

fdryer 01-18-2021 01:15 PM

Re: another revisitation on old actuator trick
I retired after 42 yrs. Fast approaching 70. The only reference I recall was something in the '70's about having flow thru ventilation in cars at all times whether the blower works or not. Mechanical linkages might be more complicated if a return spring were incorporated into actuators. The less space in hvac systems and smaller interiors of most cars doesn't lend itself to designing a mechanical setup for default position. This would imply constant power to an actuator against a return spring. Not very efficient design if this were true. I've not had the pleasure of disassembling any of my actuators yet but I did reach out in a thread for anyone willing to send me a dead actuator for show and tell and possibility of repairs to restore a part that's discontinued.

As near as I can tell, when I leave my mode setting, temperature and blower speed preset the night before, the next morning remote start powers up everything to preheat the interior. I can choose face vents or defrost, mostly defrost when I anticipate snow to make it easier to scrape it off in the first few minutes of warm-up while I scrape windows and brush off snow buildup before driving. The days I forget to select defrost, vents blow warm air. Whatever the last setting, this becomes the default setting.

rfisher 01-20-2021 11:00 PM

Re: another revisitation on old actuator trick
hi fd- know how you feel . passed 70 2 years ago. does that mean i am no longer a whippersnapper? thought that was a mental condition. never knew about the defrost default rule. dont think that could work with actuator controlled hvacs.on my L100 i only get air, hot cold or fresh from the front dash vents. remember once where i had to replace a snapped cable in a cable controlled 64 dodge and only defrost would work. that had vacuum controlled hvac functions too. thanks bob f

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