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Author Topic: No A/C Blower in 73 1/2 ton blows fuse  (Read 3237 times)

Offline reluctant mechanic

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No A/C Blower in 73 1/2 ton blows fuse
« on: November 02, 2016, 12:54:18 pm »
I've read suggestions answers from bd & Chevyrado, however I'm unable to find a heater relay at all.

  I did however discern that the squirrel cage fan was set too deep and created mechanical resistance that prevented spin, I thought I'd fixed it, but apparently not (new motor BTW).

  I also replaced the switch, however the new one is 4 prong, whereas the original was 3 prong. I'm assuming shouldn't matter, probably an off position, which the former never had.

  I'm preheating it now to get in garage, further test wire resistances,and reset squirrel cage.

Reluctant Mechanic
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Offline hatzie

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Re: No A/C Blower in 73 1/2 ton blows fuse
« Reply #1 on: November 02, 2016, 03:51:40 pm »
Quote from: reluctant mechanic on November 02, 2016, 12:54:18 pm
I've read suggestions answers from bd & Chevyrado, however I'm unable to find a heater relay at all.

The AC harness offloads the HI blower position current draw to the relay.   Does the Orange blower power wire run directly from the resistor pack to the blower?

Quote from: reluctant mechanic on November 02, 2016, 12:54:18 pm
I did however discern that the squirrel cage fan was set too deep and created mechanical resistance that prevented spin, I thought I'd fixed it, but apparently not (new motor BTW).
Jamming the squirrel cage will burn the motor out.  If the blower sits too deep you need to figure out why.  An AC blower in a NON AC housing?

 
Quote from: reluctant mechanic on November 02, 2016, 12:54:18 pm
I also replaced the switch, however the new one is 4 prong, whereas the original was 3 prong. I'm assuming shouldn't matter, probably an off position, which the former never had.
3 terminal is non AC.  4 terminal is AC. 

I question whether you have factory air installed.  No relay, shallow housing, and 3 terminal blower switch.
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Offline VileZambonie

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Re: No A/C Blower in 73 1/2 ton blows fuse
« Reply #2 on: November 02, 2016, 05:50:32 pm »
Put the correct switch in. Start at the source, unplug the blower motor, does it still blow the fuse?
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Offline reluctant mechanic

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Re: No A/C Blower in 73 1/2 ton blows fuse
« Reply #3 on: December 21, 2016, 09:27:45 am »
Sorry for slow response. It turned  out that there are 3 recommended blower motors: AC, W& W/out AC (which I had), & finally non- AC. All hold the reused squirrel cage style fan on shaft w/ hardened spring nut.
   The non-AC shaft is 1/2" shorter! I switched to it and voila, no blown fuse.
    Thx for all the help!
   


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