1998 GMC SIERRA HEATER BLOWER RESISTER

  • Tiny
  • adubber
  • 1998 GMC Sierra

Heater problem
1998 GMC Sierra V8 Four Wheel Drive Automatic

Hello I am sending anouther request on my vehicle
I have only the high setting on the fan motor

I have replaced the air actuator the heater relay the
control pannel on dash and the heater blower resitor as requested by you guys,

up until I replaced the heater relay I couldnt controll the temp it was on high always.

what next? I am so frustrated with this now.
There are two wires going into the motor one is purple and the other is black test light works on the purple on high only tried it on lowest settring 1st
I see 2 yellow wires in a harness thas is connected to something on the fire wall but no others

after looking further I found the yellow wire going into the resistor and on low it has no power going to it

Friday, January 15th, 2010 AT 6:02 PM

17 Answers

  • Tiny
  • rasmataz
  • Member

Hi adubber, Welcome to 2carpros and TY for the donation: I want you to turn heater on set it at low and check for power at the yellow wire on the blower motor resistor let me know asap

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Friday, January 15th, 2010 AT 6:18 PM
  • Tiny
  • adubber
  • Member

I testerd for power on the yellow wire with the fan on low and found no power

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Friday, January 15th, 2010 AT 6:47 PM
  • Tiny
  • adubber
  • Member

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Friday, January 15th, 2010 AT 7:49 PM
  • Tiny
  • rasmataz
  • Member

Replace the blower switch

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Friday, January 15th, 2010 AT 8:44 PM
  • Tiny
  • adubber
  • Member

What exactly are you refering to?

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Friday, January 15th, 2010 AT 9:32 PM
  • Tiny
  • rasmataz
  • Member

The switch is within the HVAC control module


http://www.2carpros.com/forum/automotive_pictures/12900_b1_9.jpg




http://www.2carpros.com/forum/automotive_pictures/12900_b2_9.jpg

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Friday, January 15th, 2010 AT 9:45 PM
  • Tiny
  • adubber
  • Member

Thats odd the new console had the switch attached
could the new switch be bad? Or could there be some other problem?

UPDATED 1-19-10
Hi,

I ran a power line from the battery terminal to the yellow wire going into the resistor and the blower run on low, I did the same with the brown and it runs the fan on med and on blue it runs on med high
the high comes on if you turn it to high before starting the vehicle
i9f you have it on any other setting and start the vehicle it don't but will turn on after a few seconds or minutes no pattern.
I tested the 25A heater fuse and its good I found a aircond- relay in the fuse box under the hood and replaced it but that didn't change
I noticed that the air cond- don't come on at first when you push the button and after a while the light on the panel turns on.

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Friday, January 15th, 2010 AT 9:46 PM
  • Tiny
  • rasmataz
  • Member

Earlier you said you don't have power at the yellow wire on the resistor-if the switch is working properly the yellow wire should power up on the low position.

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Friday, January 15th, 2010 AT 9:57 PM
  • Tiny
  • KHLow2008
  • Expert
  • 41,938 posts

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Sunday, January 17th, 2010 AT 3:56 AM
  • Tiny
  • adubber
  • Member

Hi,

I ran a power line from the battery terminal to the yellow wire going into the resistor and the blower run on low, I did the same with the brown and it runs the fan on med and on blue it runs on med high
the high comes on if you turn it to high before starting the vehicle
i9f you have it on any other setting and start the vehicle it don't but will turn on after a few seconds or minutes no pattern.
I tested the 25A heater fuse and its good I found a aircond- relay in the fuse box under the hood and replaced it but that didn't change
I noticed that the air cond- don't come on at first when you push the button and after a while the light on the panel turns on.

From: " forum@2carpros. Com" < forum@2carpros. Com> Sent: Sun, January 17, 2010 1: 56: 14 AM
Subject: Topic Reply Notification - 1998 GMC Sierra heater blower resister

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Monday, January 18th, 2010 AT 6:32 PM

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