For Cryin Out Loud! I'm COLD!

[C. M. Wolf]

Ok, I now live in MT... darned cold around here!

...And I can't get my heater fan to work to save my life!

I've replaced... the heater radiator core, the fan switch on the dash, the fuses are good, and I've replaced the heater hoses within the dash side. I've insulated/wrapped the heater hoses to the heater radiator after replacing them. The water pump is new and as big & strong and guaranteed as I could find. The thermostat is a new 160 degree unit. The engine radiator is a new 4-core,(as large as I could fit into the thing without reworking the mounts and changing the fan shroud), that is now partially covered from mass air-flow. I'm running 80% anti-freeze and plug a heater on the block at night.

So, where else is something going to go wrong or what else can I check to get the heater fan to work??

Did I mention that it gets darned COLD around here?

TIA for any and all help.

Michael

[too much stuff]

Go to a 195 t-stat and pull the blower motor and see how much junk is in there. Ask me how i know as of 2 days ago. Gets cold here too...

[swamp rat]

With your post its kinda hard to figure out.

1) is the heater motor and fan working? If not than it may need replaced. You checked the fuses, do you have a test light? you could trace the wire to the motor and check to see if it gets power. if it gets power then the motor may have to be replaced or possibly the 3 position switch, i wouldn't be able to tell from this computer.

2 Is the fan blowing but your not getting any heat? make sure the temp control lever is moving the flap door properly, its the door that regulates how much heat is brought into the cab. you should not have to wrap or insulate the hoses, i have never seen this done on my 40 years of hobby wrenching. i would probably run a 185 degree thermostat myself. Get down on the passanger side floor and activate the temp control and listen to the sounds comming from the heater box, do you hear it moving? you may have to unhook the cables from the box and activate by hand to be sure there adjusted properly.

You just replaced the heater core? is it possible you neglected to properly reconnect a wire or ground lead?

[C. M. Wolf]

Originally Posted by swamp rat

With your post its kinda hard to figure out.

1) is the heater motor and fan working? If not than it may need replaced. You checked the fuses, do you have a test light? you could trace the wire to the motor and check to see if it gets power. if it gets power then the motor may have to be replaced or possibly the 3 position switch, i wouldn't be able to tell from this computer.

I have a test light, I'll have to trace the wires I guess.
I have already replaced the three-pstn switch on the dash control panel.
It's possibly the fan motor itself that has failed. I dunno, need to check. (Can these be temporarily jumped straight from the batt without harming the motor or relays to it to check for function?)

2 Is the fan blowing but your not getting any heat? make sure the temp control lever is moving the flap door properly, its the door that regulates how much heat is brought into the cab. you should not have to wrap or insulate the hoses, i have never seen this done on my 40 years of hobby wrenching. i would probably run a 185 degree thermostat myself. Get down on the passanger side floor and activate the temp control and listen to the sounds comming from the heater box, do you hear it moving? you may have to unhook the cables from the box and activate by hand to be sure there adjusted properly.

>The fan is not running at all.<
I have re-run and lubed all the heater control cables when I replaced the inner-dash ducts and replaced the heater control panel in the dash. I am sure these are just right and working properly.

You just replaced the heater core? is it possible you neglected to properly reconnect a wire or ground lead?

This is unlikely, but not out of the question,(because I just ain't perfect, ya know). I'll double check this again.

I was wondering if this year and model has a "Heater Resistor" that might have failed somewhere within the unit,(inside the heater box unit), that I can't see?

?

Michael

[Jacfourteen]

Pull the wire at the fan and check for 12 volts with the switch set to the highest setting. Make sure that it is well grounded, because having 12v does no good if it can't get it to ground. If you have power and good ground then the only thing left is the fan motor itself.

[swamp rat]

I'm not sure about a heater resistor.

I would put a post in the electrical section of the forum asking about the resistor and jumping the heater fan direct to battery and for the electrical schematic if you don't allready have a copy

[my70chevyc10]

There is a blower resistor located on the top of the heater box inside the cab behind the glove box. I just got mine going after i changed the motor, switch, and resistor. i took a test light to the fuse box i had power going to and across the fuse but nothing coming from the back of the fuse block. so i just took the next size wire and just went stright from battery and now it works fine also got new defroster grills that go on the dash and new hose going to those grills from heater box. Now the heater will burn you up in there.

[swamp rat]

Originally Posted by my70chevyc10

. i took a test light to the fuse box i had power going to and across the fuse but nothing coming from the back of the fuse block. so i just took the next size wire and just went stright from battery and now it works fine.

The next wire size larger? No need to go any larger than the stock wire but whatever ya do you better at least put an in line fuse in the new wire to protect the blower motor and resistor.

[dan76]

I may have missed the year of your truck, but the 67-72 years have a small plastic access panel in the box (under the glove box area) when removed allows you to peer into the heater core area to determine if the door is opening...allowing air to flow across the heater core.

[cdowns]

i posted wrong