Blower Runs Constantly/Low Defroster Air Flow

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   Is the blower on a 71 Ambassador supposed to run all the time?  Even with the controls in the fully off position, the blower continues to run on low.  Also, there is very little air flow through the defroster vents, even when messing with the dampers and cables.  Does anyone have any idea what could be the cause of that?  It seems to get somewhat better with all of the dash vents closed.

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nashman50 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: May/21/2021 Location: Pennsylvania Status: Offline Points: 39	Post Options Post Reply Quote nashman50 Report Post Thanks(0) Quote Reply Topic: Blower Runs Constantly/Low Defroster Air Flow Posted: Jun/30/2021 at 9:56pm
	Is the blower on a 71 Ambassador supposed to run all the time? Even with the controls in the fully off position, the blower continues to run on low. Also, there is very little air flow through the defroster vents, even when messing with the dampers and cables. Does anyone have any idea what could be the cause of that? It seems to get somewhat better with all of the dash vents closed.

tomj Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jan/27/2010 Location: earth Status: Offline Points: 7544	Post Options Post Reply Quote tomj Report Post Thanks(0) Quote Reply Posted: Jul/01/2021 at 12:49am
	Those are completely different sets of problems. One is electrical, the other, ducting. Of course the fan in the middle but the problems are separate. The fan should have OFF LOW HIGH (or whatever and AMbo has) and off means off. Switch is broken, or if it's done this since you got the car -- you haven't told us anything about background, did this just start happening, etc? -- or someone went in and wired it funny to "fix something" (like a bad switch). Switches do fail of course, but it's unusual for an OFF position to be suddenly powered. I suspect human meddling. The duct work is almost certainly plugged with leaves, fallen down, cracked, tape and seals come loose, in other words, succumbed to age-related maladies. It seems no or few cars escape this. Usually it means pulling everything out from the dash and going through it. Heater box filled with leaves and mice nests, clogged with dust, etc. 50 years is a long time! I just did all that stuff in my 1968 American (similar enough to yours, but probably simpler). No one task was difficult, there were just many of them. spent weeks finding windshield and cowl leaks, bad heater core, foam flapper seals replaced, leaves extracted, etc. It now works as good as it did from the factory -- barely acceptable! lol.
	1960 Rambler Super two-door wagon, OHV auto 1961 Roadster American, 195.6 OHV, T5 http://www.ramblerLore.com

6PakBee Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Charter Member Joined: Jul/01/2007 Location: North Dakota Status: Offline Points: 5457	Post Options Post Reply Quote 6PakBee Report Post Thanks(0) Quote Reply Posted: Jul/01/2021 at 8:06am
	Reminds me of my Dad's '62 Dodge pickup, in the winter in sub zero weather the defroster struggled to get a 6" circle defrosted that you could see through to drive. Ah, good times!!
	Roger Gazur 1969 'B' Scheme SC/Rambler 1970 RWB 4-spd Machine 1970 Sonic Silver auto AMX All project cars. Forum Cockroach

troutwilly Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Sep/14/2007 Location: Carriere, MS Status: Offline Points: 992	Post Options Post Reply Quote troutwilly Report Post Thanks(0) Quote Reply Posted: Jul/01/2021 at 8:46pm
	What tomj says, plus, if the mechanism for changing air flow from floor to vents to defrost is controlled by a cable (like a lawnmower throttle), its possible the cable slipped its position, became unattached at either end, or broke.
	Bill O. 70 AMX

Heavy 488 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Apr/27/2019 Location: In the Status: Offline Points: 3553	Post Options Post Reply Quote Heavy 488 Report Post Thanks(0) Quote Reply Posted: Jul/01/2021 at 8:52pm
	Time to bust out the TSM. It's all in there.

tomj Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jan/27/2010 Location: earth Status: Offline Points: 7544	Post Options Post Reply Quote tomj Report Post Thanks(0) Quote Reply Posted: Jul/01/2021 at 11:17pm
	71... yeah those stupid black plastic control cables. they were brittle when new, and brittlerer (?) today. They flex slightly in operation and often crack right at the clip. When ductwork gets clogged, stiff, packed with leaves, etc, it takes more force to operate, then the black plastic cable housing cracks, and the cable no longer operates. I have not once owned a Rambler that did not need all of the crap under the instrument panel removed, cleaned, repaired, sealed, etc. Earlier ones are simple; my 1960 American has wirewound cables, no "Weather Eye" complexity, and was fixed in a day. My 68, it took me nearly a year of poking at it to get it leak-free. YMMV. The good news is everythign was cheap to fix, just a bunch of hours, cleaning, fabricating new flapper seals, etc.
	1960 Rambler Super two-door wagon, OHV auto 1961 Roadster American, 195.6 OHV, T5 http://www.ramblerLore.com

madams Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jun/26/2017 Location: Duncan OK Status: Offline Points: 603	Post Options Post Reply Quote madams Report Post Thanks(0) Quote Reply Posted: Jul/02/2021 at 6:25am
	On the early AMX/Jav cars with all the controls in the off position the fan will still run on low if the Temperature control for the AC is not all the way off. I bought a "rebuild kit" from Detroit Muscle Technologies for early AMX with all the gaskets foam covers etc. Nice kit that worked well. I have been happy with all the products I have purchased there. https://www.detroitmuscletechnologies.com/amc-68-69-70-javelin-amx-non-ac-heater-box-restoration-rebuild-kit/

george w Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Joined: Jan/27/2013 Location: New Jersey Status: Offline Points: 2899	Post Options Post Reply Quote george w Report Post Thanks(0) Quote Reply Posted: Jul/02/2021 at 8:30am
	Like madams said, like the AMX and Javelins, also on the "big body" cars the HVAC fan will run on low if the a/c temp. control knob is not turned fully CCW past the detent click.
	Long time AMC fan. Ambassador 343, AMX 390, Hornet 360, Spirit 304 and Javelin 390. All but javelin bought new.

nashman50 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: May/21/2021 Location: Pennsylvania Status: Offline Points: 39	Post Options Post Reply Quote nashman50 Report Post Thanks(0) Quote Reply Posted: Jul/02/2021 at 10:27pm
	The switch seems to move properly and we have been adjusting the cables--it's somewhat better. It seems like the switch might be bad, even though I've cleaned it.

farna Members Profile Send Private Message Find Members Posts Add to Buddy List Supporter of TheAMCForum Moderator Lost Dealership Project Joined: Jul/08/2007 Location: South Carolina Status: Offline Points: 19676	Post Options Post Reply Quote farna Report Post Thanks(0) Quote Reply Posted: Jul/12/2021 at 6:32am
	Modern cars run the fan on a "very low" speed all the time, but they are tighter than the 60s and 70s cars. If the only issue is the fan running on low I don't think I'd bother with it, but check the control positions as noted first. There should be a switch of some kind near the temp control -- that could be out of adjustment or not working -- more likely that than the main switch. There is a chance that the issue is in the resistor pack for the fans, which is inside the blower housing on 70s models so it gets cooled by moving air (60s models have the resistor pack exposed under hood -- at least through 66). You might want to check connections there.
	Frank Swygert