Hvac motor confusion

[Astro]

Hey all. 96 Sierra here.

So I'm experimenting with pushing a little more voltage to my blower motor, but I've been having some trouble with a seemingly simple task.

Ok, so I've used voltage step up converters on model aircraft and they're pretty straight forward. The converter has a certain input and output vdc range and amperage rating. If you make sure all of that is within range, you can use the pot on the converter to get the desired output voltage for whatever device you have connected to it.

So ive been trying to apply the same logic here.

I bought this converter from Amazon - DC DC Voltage Step Up Converter Boost Power Module 10-60V to 12-97V 1500W 30A CC CV https://a.co/d/7dBAWOX

And I used 10awg wire for all my connections and tested everything on full speed to take the resistors out of the equation.

Here what the issue is, finally lol.

I ran the pos/neg from the car side fan motor to the input side of the converter. Then, turn the car on, fan speed full, Output NOT connected to the motor, tested output vdc and was able to adjust the output vdc across the full range it's spec'd for. I wanted to set the voltage to like 15 or 16 vdc before I connected it to the motor.

But when I connect the output wires to the motor and run it, I cannot adjust it. It just shows about 12vdc output and that's it.

I've tried this on two different converters.

Anyway, it doesn't make sense, or at least I can't make sense of it. Disconnected from the motor, I can adjust output vdc, connected, I cannot.

Do you guys have any idea what I'm doing wrong here?

 

[Astro]

Bump.

 

[someotherguy]

I don't have the answer but I do have a question: why? If you perceive poor fan output, the most likely cause is plugged-up fins on the evaporator core, where all air in the system must pass through regardless of temperature or mode setting. This is super common on gmt400's and is somewhat easy to address without major disassembly. A 100% cleaning requires taking the hvac box out of the truck and apart, but you can get it "mostly" clean just removing the blower motor for access.

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When the evap is cold, it's wet with condensation, and dust coming in through the outside air intake builds up on it and turns into a mud cake. Any debris like pine needles or leaves end up there, too.

Richard

 

[Astro]

I don't have the answer but I do have a question: why? If you perceive poor fan output, the most likely cause is plugged-up fins on the evaporator core, where all air in the system must pass through regardless of temperature or mode setting. This is super common on gmt400's and is somewhat easy to address without major disassembly. A 100% cleaning requires taking the hvac box out of the truck and apart, but you can get it "mostly" clean just removing the blower motor for access.

You must be registered for see images attach

You must be registered for see images attach

When the evap is cold, it's wet with condensation, and dust coming in through the outside air intake builds up on it and turns into a mud cake. Any debris like pine needles or leaves end up there, too.

Richard

Haha, do I know it!

I've already dug into the box to replace the evap core a few months ago and performed a decent cleaning of everything in there. It just doesn't blow hard enough. My 2000 Jimmy blows like a beast and so does my Volt.

It still cools the cab, but it takes a while and I really like the feeling of cold air blowing hard into my face in this Texas heat.

 

[Astro]

bump

 

[kennythewelder]

Just a FYI. For a long time, the power that my fan had, blowing out of the vents, sucked. Finally, one day, the resistor went out, so I changed it. After that, the motor burnt up, so I also replaced that too. Now, it has a lot of push coming out of the vents. As strong as it was when I bought the truck in 2002, if not more air flow. It made a huge difference, replacing the resistor, and the motor. Like I said, just a FYI.

 

[Astro]

Just a FYI. For a long time, the power that my fan had, blowing out of the vents, sucked. Finally, one day, the resistor went out, so I changed it. After that, the motor burnt up, so I also replaced that too. Now, it has a lot of push coming out of the vents. As strong as it was when I bought the truck in 2002, if not more air flow. It made a huge difference, replacing the resistor, and the motor. Like I said, just a FYI.

Thank you brother. I could do that. It's not too expensive.

 

[firestoness]

Refrigerator coil cleaner is a great way to clean the evaporator without pulling the box out. My k1500 wasn't pushing any air and I found it matted with dog hair.