heater blower motor is cutting out

[jzjames]

After I changed the heater core last year, I noticed the blower motor was getting tempermental, cutting out, I would bang on it and it would start, but it got progressively worse. I thought I must have might have messed up something so I took out the blower motor again a couple weeks ago to test it, and see if it could be opened up, etc.

Started working again so I reinstalled it and connected it to a better ground, and all was good, I thought it must have been a poor ground.

Now it's on the blink again, and with the glove compartment still out, I rechecked the ground but it's no go.
I read another post about the resistor for them, could this be the problem? It's foggy weather time here in WA. and Ive got to get a handle on this.

Where's the resistor for the heater box? Can I just hook up a one-speed heater box by bypassing something?

I am lousy on electrical stuff.

[basketcase0302]

jzjames » Sat Nov 05, 2016 6:18 pm
After I changed the heater core last year, I noticed the blower motor was getting temperamental, cutting out, I would bang on it and it would start, but it got progressively worse. I thought I must have might have messed up something so I took out the blower motor again a couple weeks ago to test it, and see if it could be opened up, etc.
Started working again so I reinstalled it and connected it to a better ground, and all was good, I thought it must have been a poor ground.
Now it's on the blink again, and with the glove compartment still out, I rechecked the ground but it's no go.
I read another post about the resistor for them, could this be the problem? It's foggy weather time here in WA. and I've got to get a handle on this.
Where's the resistor for the heater box? Can I just hook up a one-speed heater box by bypassing something?
I am lousy on electrical stuff.

If you look up towards the top in my pic below, (on the back side of the plenum) you'll see the blower motor resistor, (which sounds to me like the culprit). First thing would be to make sure the plenum area is not full of leaves, (via the fresh air vents) as it could cause the motor to be bound up. And yep if the truck has been "put out to pasture" and parked under trees with leaves falling into the cab vent your probably gonna find the plenum area plugged-get ready for some work to clear it out)! The resister has two small screws holding it in if memory serves me correctly.

[jzjames]

thanks basketcase0302 for that pic of the backside of the heater box. I had forgotten how those connecters were.

It looks like I may have to pull the heaterbox out again as I think the water drip from my windshield wiper above it may have gotten on the connecter/wires causing corrosion or something there. I think that may be the culprit.

[basketcase0302]

You are quite welcome. If you have the heater plenum, (what the heater core is mounted in) out it is the perfect time to replace the cheap windshield wiper gaskets which are cheap. I had a set of the gaskets here if you need them, (page-153 part#4 in LMC below). And make sure you have some body putty to wrap around the studs when you slide the plenum back in, (both inside the cab and outside the cab) as it's another place where water and air gets into the cab.
http://www.lmctruck.com/icatalog/fb/full.aspx?Page=153