Author Topic: Blower motor speed for the AC and heat  (Read 1844 times)

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Offline 1onehotTA

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Blower motor speed for the AC and heat
« on: August 03, 2007, 05:31:28 PM »
   Anyone have any idea how fast the blower is supposed to go on high, mine is wired right off the alternator or batt I forget, but it also has a good ground and has good voltage, how fast does it spin, can you feel it inside well on high, like in a new car or are they slower, my motor may be wearing out and it is friggin hot here in PA, my AC works well, but the fan sucks.
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Offline 1onehotTA

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Re: Blower motor speed for the AC and heat
« Reply #1 on: August 03, 2007, 05:32:47 PM »
I almost forgot, I have no leaks in the ducts as I replaced and rebuilt it all at a premium believe me.  Fan jsut has no UMPHHF
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Offline Joker (§ir£Ğragon)

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Re: Blower motor speed for the AC and heat
« Reply #2 on: August 03, 2007, 07:43:47 PM »
Well, for the most part GM blower motors haven't changed much. The ones in these are very close to the one in my '94 Blazer. Same with the "squirrel cage".
Larry


Offline ta78w72

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Re: Blower motor speed for the AC and heat
« Reply #3 on: August 03, 2007, 08:30:56 PM »
You can tell the difference as you increase the blower speed.  If you can't, you've got a ground issue with the high blower relay.

Offline Eagle 1

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Re: Blower motor speed for the AC and heat
« Reply #4 on: August 03, 2007, 10:10:09 PM »
Also on "max air" the air inlet door will open and you will hear and feel the difference.  Just like cars now days with the "re-circulation" button activated.
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Offline ta78w72

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Re: Blower motor speed for the AC and heat
« Reply #5 on: August 05, 2007, 01:26:15 PM »
Eagle 1 funny you should bring up "Max".  I've noticed a specification difference between the 1977 and 1978 model years.  On a 1977, if you place the A/C selector on "Max", it defaults the blower motor to "High".  However, on 1978, there is no blower motor default and the action of the fan is solely determined by the fan switch. 

Offline bandit nz

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Re: Blower motor speed for the AC and heat
« Reply #6 on: August 11, 2007, 08:04:30 AM »
If your blower fan sucks, it may be wired in reverse, as its meant to blow  ;) jk Sorry couldnt resist that. ;) ::)

Where is this "high blower relay" located ??
My air cond is cold and heat works really well, but my fan seems to be slow also, even on high.
I can detect a change when shifting up through various fans speeds, but it is very slight, I would have expected a reasonable air velocity through the vents and heat outlets, however this is not the case. :-\
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Offline ta78w72

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Re: Blower motor speed for the AC and heat
« Reply #7 on: August 11, 2007, 10:30:36 AM »
The high blower relay is situated next to the blower resistor...which is the reddish part on the A/C box near the hood hinge.  The high blower relay is the silver part next to it.

The blower speeds work off of changing resistance in the circuit...that's what the resistor is for.  When the switch is put on "High", the high blower relay circumvents the resistor and full current is sent to the blower motor.  I had a ground issue with my high blower relay and I could only get one speed out of my blower.  I found that someone had spliced into that black wire going into the high blower relay and compromised the ground.  When I fixed that, I had all the fan speeds.

The motors get tired but they should still change speeds.  So, you might have to pull that inner wheel well to see what's actually going on.  That whole job would be about four hours.  And, once you've got the inner wheel well out, you might as well go ahead and change the blower motor and wheel.  Get the original style wheel (classic has them) rather than the aftermarket metal ones the parts places sell.  The metal ones have a different shape and can catch on the A/C box.

Before you button everything up, test the blower motor to make sure it works properly.

Offline bandit nz

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Re: Blower motor speed for the AC and heat
« Reply #8 on: August 11, 2007, 05:47:40 PM »
ta78 Thanks
I knew how they worked, just was not sure where it was all located, aside from the motor which id located reading the threads.
I'll check that relay ground to make sure its a good contact, my air velocity at the vents on high feels more like low to med, when compared to most other cars.
I'll have to get a motor imported if I need one, so I would probley just order it through Hitman.

Thanks again

Bandit NZ
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