HVAC question/help

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Texvet

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1992 SCLB with a 3 speed blower. I understand "high speed only blower isn't a rare problem. I did a search and read posts until my eyes bled.

I pulled the glove box - operated the blower switch, and heard each relay click. Not saying that means they are good (I don't know what it means). Pulled the resistor. None of the wires looked rusty, burnt or broken. I checked each wire with a multimeter, and each showed resistance (versus open circuit). Again, not saying that means it is good, because have no idea what the resistance tolerances are. As long as I was pulling parts I didn't know much about. I pulled the blower motor and jumped off the battery and to see if it bound up. It did spin sort of free (no real point of reference regarding how free it should spin), so I blew out with compressed air and dripped some 3n1 electric motor oil through some hold in the motor case. I ran if off the battery and it spun up better after being oiled.

Put the blower back in - tried it. It did get a weakass bit of air flow on low - nothing more on medium, and of course high was great.

So..... instead of throwing money at it - or just buy all 3 relays, a resistor and blower motor (there was a time before retirement - that I would have done that).

I am open for any suggestions you may have, or the order in which I should start replacing stuff.

TIA
 

east302

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Are you getting water on the passenger floor? There’s a screw in the cowl that can leak water into the blower housing, rusting out the blower.

If it ran better after oil, to me that would point to a blower issue.


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Texvet

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Thankfully, I've not had a cowl leak on this truck. Although, I've had a few in the past that did. I may put a new motor in just to have history on that part. I believe the all the parts in the blower system are original. At least there was nothing in the service records from the original owner.
 

10mm Nut

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When you mainline that blower motor straight to your battery like you did it ought to spin like crazy. It ought to try and twist/jerk out of your hand when first connected. If it's not really doing that I'd start with a new one first.
 

Texvet

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You are right 10mm - if not prepared, you'll probably drop the motor - lots of torque.
 

Texvet

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Pulled the resistor. None of the wires looked rusty, burnt or broken. I checked each wire with a multimeter, and each showed resistance (versus open circuit).

What kind of numbers should I be looking for when Ohm'ing the resistor? Or... is no burnt or broken wires and no "OL" (open circuit) good enough? A

Also - is it somewhat safe to assume that hearing each relay click as different speeds are selected?
 
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