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Heater Blower Motor Question ASAP.


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97 Deville-Digital Dash. Will the blower motor still turn on with the engine not running but key on with engine cold? Think the motor went out, but now that the car is not running I am not getting the new or old motor to turn on when plugging in. Just purchased a new motor and do not want to install if not the problem. The antifreeze is currently drained, so I cannot start the car. I do have 12.4 volts at the red lead on the plug.

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I believe when I changed the blower on my '97 I tested the new one before installing it by simply plugging it in and turning the key on, and turning the fan on high. Even if you had to start the car, it should be no problem to run it for a few seconds with no coolant. Have you done this before? Do you know that you'll need to rock the engine forward a bit to get enough clearance to install the new one?

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I believe when I changed the blower on my '97 I tested the new one before installing it by simply plugging it in and turning the key on, and turning the fan on high. Even if you had to start the car, it should be no problem to run it for a few seconds with no coolant. Have you done this before? Do you know that you'll need to rock the engine forward a bit to get enough clearance to install the new one?

Yeah, I am not worried about the install.............just confused as to why neither the old or new one is turning on with the key. Had no problems with the old one, before it went out. In my past experience, there was always intermittent problems before hand, where as this one, just quit. Yet I still have 12.4 volts at the plug. Wondering now if it is not a computer problem. ACM?

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Just a thought, have you grounded the fan?

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no.....it bolts in on top of rubber bushings (no metal to metal contact).................and one of the three plug terminals is a ground......so thinking that is not necassary, but I'll check it out. Pretty sure no need for an external ground though. I would jump it to the battery, but I already have power to the plug. And from what I understand...........to direct jump you need a resistor between the ground and gray wire.............and I don't know what size, nor do I have one handy.

Ranger: I know I can start it for a short time........I was just wondering if the ACM needed the engine to be at a certain temp to activate the fan. Guess I never paid attention if the fan previously turned on as soon as I started the car. But common sense does tell me the fan should just run with the key on............so now I am stumped even more.

Maybe I need to figure out the resitor size and test both fans off the battery and go from there. Anyone know what resistor I need?

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In my OBDI equipped 1995, ACP overide AS16 (Blower speed) allows you to vary the blower speed by selecting values between 99-0.

Presumably, OBDII vehicles do something similar?

Regards,

Warren

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There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises

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Jumping it directly to the battery will not work. Been there, done, that. You are correct about the ground. Fan normaly does not come on til the engine reaches something like 90 degrees but defrost should be on demand at any temp. Like I said, I am pretty sure when I tested my new one, I just layed it on the cowl, turned the key on. Not sure what I did after that. Might have been hi fan or defrost.

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Jumping it directly to the battery will not work. Been there, done, that. You are correct about the ground. Fan normaly does not come on til the engine reaches something like 90 degrees but defrost should be on demand at any temp. Like I said, I am pretty sure when I tested my new one, I just layed it on the cowl, turned the key on. Not sure what I did after that. Might have been hi fan or defrost.

Maybe there is a chance I got a bad fan from parts store? Think I am gonna take it back.....get another and try it. If it no worky either, then I know there is another problem. Yeah I read a few former posts on running off battery. But one said something about using a resistor with the gray wire and black I beleive. Of course I know these are solid state and I really don't want to screw it up by trying to jump the new one anyway......without a diagram of the fan. So I am just gonna take it back and try another. Weird that I have power at the plug though. Does the gray wire work through the ground or the hot. Just would think there should be a way to check with meter...........but I am not even sure how the gray wire works (ground or hot).

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The grey wire is a pulse width modulated signal from the ACM. The duty cycle dictates the fan speed.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Took the new fan back. Came home, started the car after filling coolant system. Let it warm up to 160. Plugged in original fan and it spun intermittently. Went and bought an AC Delco ($250) fan, came home, plugged in.........spins like a top. Still a bit confused..........but atleast it works. Now just need to install. Oh well, atleast not the ACM.

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Just lends more credence to Bbob's aftermarket theory.

Jeeze, you would think the aftermarket industry could get a simple blower motor right. I realize it's PWM, but that hasn't been a secret since the '50s.

Oh well, you live and learn.

Regards,

Warren

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There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises

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Installed it in less then 10 minutes. The newer AC Delco has a more flexible fan blade and was able to massage it into the hole without moving the engine, displacing any wires, or cutting the housing. Thanks for all the input.

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Hmm, I did the same thing ........the first time. I say first time because apparently I massaged it too much and 6 months later the squirrel cage literaly exploded. I think I even posted pictures here. The second install went a little faster because I was expirienced :lol:

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When I did the job on my '96 about 5 years ago, I had a hell of a time installing the new blower - the squirrel cage was slightly larger than the original but I did it without cutting the housing. If I ever had to do the job again, I'd just remove the dogbones and lower/tilt the cradle to gain additional room.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Kevin,

No need to lower the cradle. After removing the dog bones, replace one with a turn buckle and pull the engine forward an inch or two. That will give you just enough clearance to wiggle the new one in.

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I'll remember that - I shouldn't need to repeat the job on the '96 as it has the new design blower but the '97 still has the old style blower.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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I could be *very* wrong on this, however I seem to recall someone having said that connecting the grey (PWM) wire to ground through a 1000 ohm resistor would cause the fan to operate.

I don't remember having seen a resolution on that question. Maybe someone with a blower motor and a 12V supply might answer?

Regards,

Warren

Posted Image

There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises

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