heater won't work

[dman1982]

so last winter my heater worked in my truck, now its not, getting closer to winter i want to fix this before hand so that way I'm not stuck there with frozen windows, i just changed out the blower motor and no luck

i thought i posted a thread similar to this but went through and couldn't find it, i went to check my fuses and didnt know which one was for the heater so a diagram of a 84 k10 would be helpful, any other ideas besides a fuse?

[Just call me Sean]

Is the heater not working or is the blower motor not working?

[dman1982]

my bad...the blower motor isn't kicking on

[wilkin250r]

Does it not blow at all? I've seen some with faulty switches or bad resistor packs that only blow on "High".

If I had my truck in front of me, I'd take pictures and show you how to pull the power and ground off the motor and apply power directly. This will tell you whether your problem is in the motor, or in the switch and wiring.

Does your truck have AC? (regardless if it actually works or not), it adds a few more components into the mix.

[dman1982]

before it totally quit, it would only work on high, then it just quit, it did have a/c at one point

[67swb72klb]

a lot of times it is a ground or the resistor in the heater box

[dman1982]

where is the grounds for the blower motor? i seen the one that is actually on the motor, but there is more? and is the resister the silver thing on the a/c box?

[wilkin250r]

When you say "silver thing on the AC box", most likely you're looking at the Relay, it kicks the fan on high when the AC turns on.

The ground is the chassis of the blower motor itself, most often they have a star washer and a dedicated ground wire also, rather than rely on the chassis contact itself.

Here is a picture (pulled from this site) that shows two blower motors. The "power" input is the electrical terminal sticking out of it. You can put 12V directly to that and verify if your motor is working or not. However, I would only contact it briefly the first couple of times, if your motor is worn out you might burn it out.

[wilkin250r]

Here is a picture from the same thread, showing the motor installed with the typical ground wire from the chassis of the fan to the body.

Like I said, all you need to do is pull the power wire off, and use a jumper wire directly from the battery and touch it to that terminal. This will tell you if your fan is working, and thus tell you if your problem is with your fan, or with your switches/wiring/other components.

[Just call me Sean]

The fan itself doesn't have a fuse, it has a fusible link. It's bolted to the junction block.

[dman1982]

Originally Posted by Just call me Sean

The fan itself doesn't have a fuse, it has a fusible link. It's bolted to the junction block.

do you have a pic by chance? i changed the motor and relay and still nothing, getting kinda frustrated with this

[dman1982]

and is it common for the switch cluster to go bad? (you know where you control the heat fan etc)

[67swb72klb]

as long as you know the motor is grounded the switch must be bad but check for power going to the switch first
good luck

[dman1982]

i think while doing my LS swap i may have cut into those wires

[dman1982]

so with my LS swap there was a little box bolted to the fender well, does anyone have a pic of this? i took it off and dont remember how it goes in there

[motornut]

not sure if this will help....relay and resistor?

[dman1982]

Originally Posted by motornut

not sure if this will help....relay and resistor?

so the a/c harness asm is where the power comes from i take it?

[motornut]

Originally Posted by dman1982

so the a/c harness asm is where the power comes from i take it?

heat or blower gets power from the heater fuse

[dman1982]

Originally Posted by motornut

heat or blower gets power from the heater fuse

the heater fuse is the thing right above where the distributer use to be? looks like a solenoid?

[Just call me Sean]

Originally Posted by motornut

heat or blower gets power from the heater fuse

No, the blower gets power from the junction block.

Originally Posted by dman1982

so the a/c harness asm is where the power comes from i take it?

That is the junction block, it feeds the relay which feeds the blower.

[dman1982]

Originally Posted by Just call me Sean

No, the blower gets power from the junction block.





That is the junction block, it feeds the relay which feeds the blower.

gotcha, so the junction box looks like a solenoid and gets wired to the harness that goes to the blower motor?

do i just need to add constant 12 volts? got a little cut happy when i did my swap haha

[Just call me Sean]

The yellow broom handle points to the junction block where the fusible link attaches. It feeds the large red wire on the relay which feeds the blower motor. You can see the red wire in my pic but mine is rigged at the moment.

[dman1982]

Originally Posted by Just call me Sean

The yellow broom handle points to the junction block where the fusible link attaches. It feeds the large red wire on the relay which feeds the blower motor. You can see the red wire in my pic but mine is rigged at the moment.

in the marine corps we called this barney style...what I'm used to...im pretty sure i can get it now....i did tape up all the old wires that goto the blower motor so i should be able to get it pretty quick in the morning

[motornut]

Originally Posted by dman1982

the heater fuse is the thing right above where the distributer use to be? looks like a solenoid?

No I have a fuse in the box marked for it.
With or without AC

[dman1982]

with