heater fan - always on?

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74 Shortbed

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It's not for dust, it's to keep moisture out of the ductwork so it don't build up mildew..
 

smoothandlow84

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It's not for dust, it's to keep moisture out of the ductwork so it don't build up mildew..
And thats probably why drug smugglers dont like using the squares vents to hide their shipments. The constant on feature would give them away with either odor or pixie dust blowing out all over the cab...lol
 

74 Shortbed

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And thats probably why drug smugglers dont like using the squares vents to hide their shipments. The constant on feature would give them away with either odor or pixie dust blowing out all over the cab...lol
Probably right there, lol.. :D
 

smoothandlow84

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"It's magic dust man". "A little bit to the reindeer, a little bit to santa clause, a little more to santa clause, a little more to santa clause
 

Rusty Nail

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Meh.
My effing blower is in its' death throws and makes a TERRIBLE sound, sometimes. If I hit a bump, it starts making the noise and since I can't turn it off, it never stops after it starts unless I unplug the purple wire or turn the truck off.

Handy!

Sometime if I pat it (the blower) it will settle down but not often.

I don't have interest in 40 year old trucks because I want them to do **** I don't tell it to. Like ABS, for example. I hate ABS so I drive square bodies.
The lack of control in the HVAC is very,very unwelcomed IDGAF what the "purpose" or "intention" is, the answer is no. Lol maybe in your truck that's okay but not in mine. My 40 year old truck has an automatic transmission and that's enough automatic for me.

Ima look into this tab bendy thing , that's the type of solution i'm after! Can I simply kill the uber lowest speed on the switch? That would be ideal. Use that for off.

See, it was never an issue because I had no hi-speed blower function and that position was effectively "off".
And since my K5 rides like an Ox cart, my "Rough Country" 2 inch lift leaves much to be desired. I don't understand how it rides SO ****. Focking ridiculous. Thinking new shocks.
Im hangry venting, you all aren't motherfuckers lol.

Well, not all of you...some of you I block.:mad:

Nobody noticed I topped a 2013 thread post search feature use for teh lulz? Is this the internet?:(


Lemme guess. None of you motherfuckers know what a 9/16, 350 is? Srsly?
A 5/8, 350 even?
Might as well ask a engine question and not get pissed off twice.

Quick, go google it.
 
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smoothandlow84

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I might know what you're talking about...but I will need to translate further.




:Insane:
 

HotRodPC

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Not sure which system you have some of them aren't a high medium low, some are just adjustable blower on a slide switch. In that case, the Top switch needs to be turned to OFF, then the blower will shut off even if your blower speed switch is all the way down to the lowest it'll go. I think the heat only systems are blower OFF Low Med High, but AC Trucks the top slide switch has to be in the OFF position or the blower runs on low IIRC.
 

74 Shortbed

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I think the heat only systems are blower OFF Low Med High, .
My 74 beater is a heat only and it runs all the time, also my 78 donor was a heat only and it ran all the time..
 

MtBraun

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Good to know. My 78 fan runs all the time. This time of year I like it. During our one nice month of the year (July) it can get a little warm. I like the idea of installing a valve on the heater line.
 

74 Shortbed

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Could put a toggle switch in that way you could shut it off when you want.
 

Snoots

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Do you have A/C? If yes, read on.

Take a look at the schematic on the right side.
If your control lever (top one) is in the 'OFF' position then there is no power to the fan AT ALL.

If your fan is still running then you have a problem with the control lever switch.
 

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SirRobyn0

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Not sure which system you have some of them aren't a high medium low, some are just adjustable blower on a slide switch. In that case, the Top switch needs to be turned to OFF, then the blower will shut off even if your blower speed switch is all the way down to the lowest it'll go. I think the heat only systems are blower OFF Low Med High, but AC Trucks the top slide switch has to be in the OFF position or the blower runs on low IIRC.

Pertaining just to square bodies what @HotRodPC has said is correct HVAC operation. The blower motor will shut off if you more the top lever to OFF. I've worked on a fair number of squares in various condition and I've never seen one that didn't shut the blower off with the top lever slid all the way left to the OFF position. The cars maybe another story.

I have a 78 square in the shop right now that is heat only and the top level is labeled, off - heat - def the fan switch is labeled low - med - high.

My 84 is like this. Top lever off - max air - norm - bi-lev - vent - heat - def fan switch is low - med low - medium high - high.

Both trucks will shut the fan off if the top level is slid to off.

However and this is what I think makes some guys think the fan is on all the time, these trucks have great flow though ventilation meaning that if your driving a long at speed air will come though the heater because of ram air effect at the heater intake. When you move that top lever to off the blower fan shuts off and the door inside the HVAC system should go to the recirc position for A/C equipped, thereby stopping the flow of outside air. For non-A/C equipped vehicles IIRC, the door just shuts outside air off as there is no recirc provisions for a heat only system. Then if for some reason that door doesn't seal well or doesn't fully move to the closed position then air will still flow in even though the fan is in fact off, and this is a pretty common issue.

That is how every square body I've ever seen has worked, that's not to say that there might not be an oddball heating system, but I really think the ram air effect has people mistaking it for low speed fan operation.

Also the door allowing air to flow though all the time is what leads guys to install a coolant shut off valve, which at least stops the air flowing in from passing over the heater core in a non-A/C truck.
 

Turbo4whl

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@SirRobyn0

To repeat what has already been stated, early squares without AC, the fan always runs. Not many differences between the 73's and 74's. My 1974 Jimmy I bought new in 1974, the blower was on with the key. No off for the fan.
 

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