Testing Fan Switch

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May 30, 2008 | 07:44 PM

boatnfish

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Mountain Pass

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Testing Fan Switch

2001 F150 4x4 supercab

Lost #2 speed on the fan, #1, #3, and #4 seem to work fine. Actually, I guess I could have lost #1 speed as well but I don't remember how much air that speed moved.

I have pulled the switch, and get the same readings (infinite) on an ohm meter across the various terminal comnbinations for speeds #1 and #2. Speeds #3 and #4 I get continuity across different terminals for the two speeds.

Looking if someone can tell me what combinations for each fan speed I should be seeing on the various terminals?

I think the issue is the switch and not the resistor pack.

Thanks in advance

May 30, 2008 | 08:04 PM

jimm66

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From: Green Bay WI. / Wawa Ont.

Don't know what you are suppose to have across those terminals, but it's almost always the resistor ckt in the plenum. Why do you think it's the switch?

May 30, 2008 | 08:14 PM

boatnfish

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I am thinking the switch because when I check various combinations of terminals, I get the exact same readings for the lowest two speeds, which is infinite ressitance across all terminals. The higher two speeds I get get different combination of readings across the different terminals.

With that I think it is the switch as I don't see any difference between the number one and number two speeds.

May 30, 2008 | 08:22 PM

jimm66

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From: Green Bay WI. / Wawa Ont.

On the resistor ckt the lower speed resistors burn out first. If you have the same reading then 1&2 speeds are gone. You have 2 different readings across 3&4 so they are still working. I believe the resistors! Then of course I could be wrong. Like many other times.

May 30, 2008 | 08:27 PM

boatnfish

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I will look at the resistor tomorrow AM, much easier to pull the switch first.

On the SWITCH, the readings I am getting are:

Speed #1
Terminals Ohm
1-2 infin
1-3 infin
1-4 infin

Speed #2
Terminals Ohm
1-2 infin
1-3 infin
1-4 infin

Speed #3 Ohm
1-2 0.2
1-3 infin
1-4 0.1

Speed #4
Terminals Ohm
1-2 0.2
1-3 0.4
1-4 infin

Jun 5, 2008 | 06:40 PM

boatnfish

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Mountain Pass

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okay, so once the rain stopped I got out and pulled the blower motor resistor. It was rusted, broken, etc.

When picking up the resistor at the local dealer i asked him about the switch. The kid at the parts counter didn't know, but a meter on a new one and got the same readings as mine. He did know to ask if I needed the connector as they tend to melt.

Put things back together, and good to go.