Resistor Pack & how I fixed it.
09-08-2004, 09:22 AM
#1
6th Gear
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Resistor Pack & how I fixed it.
The A/C-Heater blower was driving me crazy because sometimes the fan speeds 1-3 would work just fine and sometimes they wouldn't work at all. I brought this problem up on this list and immediately got responses identifying the Resistor Pack as the source of the problem. Thanks guys!
My first response was to just buy a new resistor pack but the fine folks at ZIMS told me that the price was well over $200. Yipes!
So I pulled the resistor pack to have a look at it. Just two screws hold it onto the top of the blower housing under the hood, below the black plastic cowl cover. Once I saw the unit out I knew immediately what the problem was.
The design is heavy duty, a bit too heavy duty actually. The pins for connecting to the wiring harness plug are a rivet design on the other end. The various loop resistor wires are riveted to the various pins. Such a design is suitable for high current demands but over time can suffer corrosion within the riveted connection itself. This tendency is especially troublesome if current demands are low as the riveted connection never gets warm enough to keep itself clean. Also riveted connections can loosen with age, vibration and oxidation. In this case, because all three resistor loops would either work or not work as a group, it was probably the combined ground connection pin that had corrosion or looseness within the connection.
I wasn't quite sure which pin was the ground connector but it didn't matter. I set out to tighten all of them. First I blew all the dust out with an air hose. Then, because I had a can of it, I shot some carb cleaner all over it and again blew it out. Brake cleaner or genuine electrical cleaner would work too. This is a heavy-duty electrical design, not some delicate electronic circuit board.
Then I turned the resistor pack upside down and clamped the pins securely in the vice. I took a small, pointed punch and a hammer, then used them to center punch each of the riveted pin connections. The effectively pushes the stem of the rivet out to a larger diameter and also tightens the rivet itself. The rivet stem is soft so it deforms easily -- which is exactly what is needed.
Just as quick as that my problem was fixed. The random work-or-not-work situation has completely gone away.
My first response was to just buy a new resistor pack but the fine folks at ZIMS told me that the price was well over $200. Yipes!
So I pulled the resistor pack to have a look at it. Just two screws hold it onto the top of the blower housing under the hood, below the black plastic cowl cover. Once I saw the unit out I knew immediately what the problem was.
The design is heavy duty, a bit too heavy duty actually. The pins for connecting to the wiring harness plug are a rivet design on the other end. The various loop resistor wires are riveted to the various pins. Such a design is suitable for high current demands but over time can suffer corrosion within the riveted connection itself. This tendency is especially troublesome if current demands are low as the riveted connection never gets warm enough to keep itself clean. Also riveted connections can loosen with age, vibration and oxidation. In this case, because all three resistor loops would either work or not work as a group, it was probably the combined ground connection pin that had corrosion or looseness within the connection.
I wasn't quite sure which pin was the ground connector but it didn't matter. I set out to tighten all of them. First I blew all the dust out with an air hose. Then, because I had a can of it, I shot some carb cleaner all over it and again blew it out. Brake cleaner or genuine electrical cleaner would work too. This is a heavy-duty electrical design, not some delicate electronic circuit board.
Then I turned the resistor pack upside down and clamped the pins securely in the vice. I took a small, pointed punch and a hammer, then used them to center punch each of the riveted pin connections. The effectively pushes the stem of the rivet out to a larger diameter and also tightens the rivet itself. The rivet stem is soft so it deforms easily -- which is exactly what is needed.
Just as quick as that my problem was fixed. The random work-or-not-work situation has completely gone away.
09-08-2004, 05:26 PM
#5
Race Car
I wonder if you could solder the rivets as well? Might help keep them from corroding underneath, as well as keep them in place.
I've never seen this thing up close, so I may be way out in space.
FWIW, Brake cleaner, and electronics cleaner are VERY similar. Only real difference is brake cleaner tends to be charged with CO2, to keep people from using it as a propellant (yeah right, still works great). Both are mostly hexane and isopropyl alcohol.
I've never seen this thing up close, so I may be way out in space.
FWIW, Brake cleaner, and electronics cleaner are VERY similar. Only real difference is brake cleaner tends to be charged with CO2, to keep people from using it as a propellant (yeah right, still works great). Both are mostly hexane and isopropyl alcohol.