Heater Fan doesn't blow on low

[kna4977]

I’ve got medium and high now. On low the fan doesn’t blow at all but the resistor turns red. Also turns red on medium but the fan also blows.

[dmjlambert]

You're making progress. The bearings could be going out on the blower motor, or your squirrel cage fan maybe rubbing on something. If taking the blower motor out I recommend treat the rubber hose that goes between the motor and the evaporator casing with care, because it is not reproduced. Mine was cracked and I restored it to reasonably good condition with super glue and black RTV.

[kna4977]

Originally Posted by dmjlambert

You're making progress. The bearings could be going out on the blower motor, or your squirrel cage fan maybe rubbing on something. If taking the blower motor out I recommend treat the rubber hose that goes between the motor and the evaporator casing with care, because it is not reproduced. Mine was cracked and I restored it to reasonably good condition with super glue and black RTV.

I’ve tried new switch which it needed anyway. The old one worked but was dangerous and would spark. New resistor no change, fuse and grounds are good. New relay no change. Anything else it could be besides the blower motor itself? Parts are cheap and I can return the ones I don’t need.

[Rust_never_sleeps]

you could hit the positive term on the blower motor with a direct battery wire and see how it spins before you pull it apart

[kna4977]

In the process of replacing the blower motor as that’s what ended up being the sole issue. Have the old one out and the new one painted and prepped to go in. Looks like the motor was sealed at some point likely many years ago with light gray RTV that is brittle and cracking now.

What did the factory use? Would it have had a gasket, strip caulk, rtv or? I’ll need to smooth the blower motor box surface before I reinstall. Also the old motor has the squirrel cage, flat washer, star or windmill like washer and a square piece that I believe inserts into the back of the squirrel cage but not sure. How is it supposed to go on? When I pulled apart it all kinda jumped off then fell in the floor so I’m not sure what’s right.

[Rust_never_sleeps]

THe book refers to "non-hardening sealer", so probably seam sealer back then.
You could use whatever you want now

[kna4977]

Originally Posted by Rust_never_sleeps

THe book refers to "non-hardening sealer", so probably seam sealer back then.
You could use whatever you want now

Non-hardening sealer to me sounds like strip caulk. The same stuff they used around the upper line on the a/c. Nasty stuff, very black and sticky. Like tar but a little more solid. I have some I bought for a restoration 10 years ago that's been left in a hot garage since and untouched that is the same as it was then.

[HO455]

Here's a couple photos on how the cage assembles to the motor.

For more information on non-AC heater boxes see the page in the link and the previous page too.

http://67-72chevytrucks.com/vboard/s...698377&page=42

You can get the correct non-hardening sealer at NAPA for almost $50 or you can get screen door sealer for $8 as shown.

[kna4977]

Originally Posted by HO455

Here's a couple photos on how the cage assembles to the motor.

For more information on non-AC heater boxes see the page in the link and the previous page too.

http://67-72chevytrucks.com/vboard/s...698377&page=42

You can get the correct non-hardening sealer at NAPA for almost $50 or you can get screen door sealer for $8 as shown.

Thanks that’s how I did it but mine has a flat washer and a star washer too. Put flat on them star then the alignment clip. I used 3M strip caulk that I’ve had for years.