Need some help troubleshooter my heater

[coggonobrien]

Hi guys,

I have no/very little air moving the air ducts of my 69 blazer k5 custom. it is a non-air truck with the 3 lever and toggle switch hvac controls. when i turn the key on i can hear the motor moving (albeit it is very quiet with the hood opener and no top on the blazer. Also the 2 top levers (defrost and air) are broke off/missing and have been since before i got the blazer.
What's your thoughts?

Thanks,
David

[smn69]

Originally Posted by coggonobrien

Hi guys,

I have no/very little air moving the air ducts of my 69 blazer k5 custom. it is a non-air truck with the 3 lever and toggle switch hvac controls. when i turn the key on i can hear the motor moving (albeit it is very quiet with the hood opener and no top on the blazer. Also the 2 top levers (defrost and air) are broke off/missing and have been since before i got the blazer.
What's your thoughts?

Thanks,
David

Just hooked up my controls in my 69 C10. The air flow is controlled by the connection on the bottom of the air box. I have heard that the shaft can break or the flap inside can come loose. Disconnect the cable and see if you can tell if the flap inside is moving with the shaft. The cable on the front of the air box controls the heat/defrost setting and the long cable that goes to the heater core controls the heat. It could also be that your blower housing is filled with leaves and mouse nests or any number of other things. If you have not had it apart, it might be a good idea to check and make sure it is all clean on the inside. I know when I took mine apart, it had a bunch of crap in it.

[truckster]

It also depends on where you're talking about air moving. If you're talking about the defroster ducts, those tend to come loose or totally disintegrate after 40 years or so.

[coggonobrien]

gotcha, where else are there ducts? just by your feet?

[coggonobrien]

also how much of a pita is it to replace them

[AirSpeed]

You should be able to move the levers from the backside of the controller to see if it makes a difference, you should also hear three different speeds as you adjust the middle lever, reach behind and move it back and forth. If you don't hear three speeds try wiggling the plug on the switch around, it may just have a bad connection. You can easily remove the interior heater box to see if anything is plugging it up from the inside or if any of the doors are not moving all the way. Most the time the other side of the heater core gets all the leaves and crap and for that you need to pull the box under the hood. Mine came off with no problems but I have read that others have had to remove the hood hinge. I had the same problem with my heater, it turned out to be a bunch of problems, my heater core was plugged up with years of leaves and a couple mouse nests, the foam gasget around the heater core housing against the firewall under the hood had fallen out, there was no gasket around the heater core lines going in and out. I went ahead and removed the heater boxes inside and out, replaced the heater core because it was easy to do and cheap, you may as well replace it if you got it torn apart! I used some thick closed cell foam weatherstripping for the firewall gasket and some short pieces of pipe insulation where the heater hoses connect to the core. I lubes up the detent tabs on the doors inside the heater box and now my heater blows lots of hot air! My defroster actually melts ice now!
It's really worth the time to just take the entire system out and clean it up, you should be able to do the entire job in a couple hours. My local NAPA parts store had a core in stock, I think it was around $35, I wouldn't take it apart without replacing the core now, they usually leak and or plug up once they've been in there so long.
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[coggonobrien]

ok another question on the heater controls, mine has the three levers but it also has a toggle switch.......switch appears to be non-factory and it is turning the blower on/off. all the catalog's i see do not sure any kind of switch unless its a/c. think somebody cobbed the system together? if so i'm guessing i'm better off replacing the control unit. i have one out of my 68 but i think that was 2 levers.
David

[AirSpeed]

Is the toggle switch mounted in the controller? Sounds like an AC type controller to me. The 68 controller should have three levers as well and should work fine, I would replace it, it will make things a lot easier to work with.
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I just noticed you said it looks "non factory" is the switch on the right side of the controller? Is the face made out of clear plastic? You can look at LMCs or Classic Parts website to compare it. You should order a catalog from both, the LMC catalog has a lot of exploded views and is great for referencing stuff, LMC is usually more expensive though.

[coggonobrien]

yea its mounted right in the switch, similiar but not exactly like this switch

i guess at least i have extra parts since i have the complete 68 pickup. would i need just the defroster duct kit's readily available or should there be more ducts with a regular heater unit?

[coggonobrien]

the rocker switch is location in the area i highlighted in red. basically fills the whole spot

[cdowns]

remove the blower motor then scoop out 40years of crap that is built up in the housing tends to allow for better air flow

[coggonobrien]

ok is there any differance between a 1968 or a 1969 heater setup? curious if i can pretty much cannibalize my 68 for parts. also in regards to the switch i wonder if that was done to bypass a bad resistance switch.

David