Hi,

I have 2 questions regarding the blower on my 75 k5....

1) Only hot air comes out of the vents when the truck is warm... Doest matter what i set it to.... Is this normal? Easy fix? Switch and vent controller seems to be working fine otherwise...

2) The blow is really weak... it has 3 stages, OFF, 1 and 2 where 2 is the highest speed... Unfortunately its really weak even at speed 2... Is this normal or could it be fixed?

Maybe i need a new motor.... ?

Thanks!

 

Have you crawled under your dash to see where the cables go? There is a door that will divert the air source away from the heater core, your's may be either out of adjustment or broken. I think there is a foam seal too which over time (30 years should do it) will just wear out.

As far as the blower, this could be three things. First, it could be the blower like you guessed. Second, the resistor could be bad causing a drop in voltage to the motor. It is simple to replace the resistor, it has a three prong plug on it and will be in the engine compartment bolted to the HVAC box. Two screws and it's out. Once out you will see what look like springs. Third could be another symptom of your HVAC seals. Your blower might be blowing just fine but because of leaks at various places it is not building up enough pressure to force the air through a specific opening, like the floor register or the defrost vents.

 

Hey Thanks for reply =)

Ive been under there but not knowing what to look for things were looking ok...

I noticed theat my fan controller has LO * HIGH.. on LO there is nothing... maybe the high mode is missing... and that its moving from low to mid and now low mid high.

You have given me some good pointers and i will take a peek the coming weeknd and see if i can figure out something =)

BR Jonas

 

another thing to add is if the motor sounds like its blowing at full speed and theres no leak and barely anything is coming out, i had a mouse who moved into my heater box and installation coverd up 80% of the heater core so it made high feel like low

 

oi ahaha... better take my apart then.... :P

 

you might be able to just pull out the resistor and look into the hole to see if its being blocked, i only found out cause my heatercore was leaking and noticed the mess when iw as in there.