Blower motor won't stop running Help

[TurnNBurn]

Hello I have had many old chevys like this. Where in the summer you open the hood and unplug the blower, but I want to fix this one. The truck i'm doing is a 78 1/2t 2wd. The fan control will not shut the blower motor off. I first off bought a new blower resistor in the heater box. That did not work, I have speed control now but it wont shut off. What do I try next?? The fan switch maybe??? btw no factory A/C

[GMC Guy]

i think they'll all like that. maybe you could hook up an in-line switch to the blower. i dunno what much else you can do.

[gchemist]

The fan is designed to run all the time. You'll have to install a bypass switch to turn it off.

[TurnNBurn]

seriously wow ok

[TurnNBurn]

does any one know why

[78 Big10 454]

I bought my 78 new in Dec. of 77. The salesman made a big deal of the blower being on constantly, calling it "Astro-Ventilation" or something of that sort. After 32 years, I'm used to it.

[TurnNBurn]

OK Thats really odd, Do you know where I can find anymore info on this.

[spinem]

it runs all the time, chevys idea was to keep the heater core cool due to direct water pump-intake manifold hook up (not radiator hook up).... you can put an inline switch on it but make sure u use a beefy switch or a relay.

[ToughBowtieTruck]

Yep....I got rid of this little "option" a long time ago.

Here is how to do it:

You need to pull your dash bezel cover off, and unplug the harness from the fan switch. On the plug you will see I think a brown wire that jumps to 2 terminals at once. One of the terminals is the power to the switch and one is for the low speed, hence making the fan run all the time on low. You can cut that wire out - but be warned you will then only have medium and high speeds left. I don't care about low anyhow, truck is still cold in the winter on high ha ha.

[Mr.Scary]

my question is why would you even wanna stop it from running? its been doing it for years and hasent hurt anything, i dunno just my 0.02 i guess

[Keith Seymore]

Originally Posted by TurnNBurn

Hello I have had many old chevys like this. Where in the summer you open the hood and unplug the blower, but I want to fix this one. The truck i'm doing is a 78 1/2t 2wd. The fan control will not shut the blower motor off. I first off bought a new blower resistor in the heater box. That did not work, I have speed control now but it wont shut off. What do I try next?? The fan switch maybe??? btw no factory A/C

Do you mean it runs full blast, like even after you shut the truck off and remove the key?

Or are you saying it runs at a low speed (only when the key is in the "on" position) even when you think the system should be "off"?

K

[ToughBowtieTruck]

Originally Posted by Mr.Scary

my question is why would you even wanna stop it from running? its been doing it for years and hasent hurt anything, i dunno just my 0.02 i guess

Way too hot in the summer for me.

[joe231]

I just clipped the yellow wire at the blower resistor to get rid of low. I didn't need low anyway. And to kill the heat in the summer, I put a manual shut off valve in the heater hose. Made it much better.

[TurnNBurn]

The Blower shuts off when I turn key off. I just thought that it should shut off when I tell it to. Also Its not really needed when its 100 above with 85% humidity. Its hot enought just running around town. I just find it odd that is doesnt shut off. I thought every pickup I have had has this problems.

[Keith Seymore]

Originally Posted by TurnNBurn

The Blower shuts off when I turn key off. I just thought that it should shut off when I tell it to. Also Its not really needed when its 100 above with 85% humidity. Its hot enought just running around town. I just find it odd that is doesnt shut off. I thought every pickup I have had has this problems.

Ok, thanks.

I had a different problem: the blower was stuck on High no matter where I put the switch, and then remained running even when I shut the engine off and removed the key. I had to pull the power wire to the blower motor to keep the battery from running down.

After doing this for a couple days it finally "healed" itself. There is a module mounted on the case that is suspect; I will replace that module first thing if it ever does it again.

Thanks for the followup -

K

[68_Step]

Originally Posted by gchemist

The fan is designed to run all the time.

I had no idea they ran all the time - learn something new everyday in these forums.

Does it also run on low on a 67 C10? Or just square bodys?

[78-5.3]

on the note on the blower not turning off my blower doesnt work i pulled my blower and it dont spin freely also the fuse got really hot and blew could the fact its hard to spin make it not work and blow a fuse!!

[flamingbig10]

Originally Posted by 78-5.3

on the note on the blower not turning off my blower doesnt work i pulled my blower and it dont spin freely also the fuse got really hot and blew could the fact its hard to spin make it not work and blow a fuse!!

yes