switch help
Moderator
Joined: Jan 2001
Posts: 56,992
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From: Virginia
You probably need a new resistor assembly. Go out and look in the ductwork, you should see a square thing with several wires going to it mounted in the duct. Take it out and it will look like a bunch of springs. See if any of them are burnt out.
Here's what it looks like.
Here's what it looks like.
Lead Driver
Joined: Jul 2009
Posts: 6,477
Likes: 19
From: Sheffield, AL
Welcome to the forum, rustyfordhibbard!
My experience has been that the resistors burn out due to the blower motor either going bad or being under a heavy electrical load due to the fan/blower running against leaves or other debris that has made its way into the duct work. Has the fan ever made a screeching noise?
It is always a good idea to annually remove the blower assembly [located next to the resistor] and clean out the duct work. There have been dash fires caused by the hot resistor igniting dried leaves.
By the way, the resistor is located in the duct work so that the moving air helps cool the wire coils. The fan high speed bypasses the resistors.
My experience has been that the resistors burn out due to the blower motor either going bad or being under a heavy electrical load due to the fan/blower running against leaves or other debris that has made its way into the duct work. Has the fan ever made a screeching noise?
It is always a good idea to annually remove the blower assembly [located next to the resistor] and clean out the duct work. There have been dash fires caused by the hot resistor igniting dried leaves.
By the way, the resistor is located in the duct work so that the moving air helps cool the wire coils. The fan high speed bypasses the resistors.
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Joined: Oct 2015
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switch help
Thanks for the replies guys! This ductwork is in the cab of the truck, yes? Because I have the fan out and don't see anything like the pictures under the hood. I'll look there in the meantime.
pedant
Joined: Jan 2008
Posts: 23,576
Likes: 40
From: EXTREME southwest CT
The resistor block is screwed into the plastic plenum under the hood.
The wire coils are inside the plenum with the harness connector facing out.
Most often it is not the coil that burns through, but the little thermal fuse. (Otherwise you would only lose *one* of the intermediate speeds)
I actually replaced my fuse for $0.69 a week or two ago.
The wire coils are inside the plenum with the harness connector facing out.
Most often it is not the coil that burns through, but the little thermal fuse. (Otherwise you would only lose *one* of the intermediate speeds)
I actually replaced my fuse for $0.69 a week or two ago.
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