1998 GMC Sierra heater blower resister

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

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

[quote:8b7993ae84="adubber"]I testerd for power on the yellow wire with the fan on low and found no power[/quote:8b7993ae84]

Replace the blower switch

what exactly are you refering to?

The switch is within the HVAC control module

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.

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.

[quote:0f3d9f4791="adubber"]Electrical problem
1998 GMC Sierra V8 Four Wheel Drive Automatic 115,00 miles

Hello again,

I am the guy with the gmc sierra i replaced the controll console for the haeter and air cond- I replaced the relay for the fan I replaces the air door actuator, I replaced the heater blower resister
you asked me to test the yellow wire going into the resister with the fan set on low and i did this finding no power. what next?

I am will to pay more for the advise if needed.[/quote:0f3d9f4791]

[quote:0f3d9f4791="KHLow2008"]Hi adubber,

You should have replied to your previuos post so that whoever was attanding to you can get notification and attend to you as soon as he gets online.

This would keep the history of what had transpired to allow an easier understanding of the problem and recommendations and repairs carried out.

Please do not edit the post as no notifications would be sent out.

Let me know the following.

With blower control speed at Low, you have no power supply to the yellow wire. Let ma know the following.
1. Do you have power at the Tan wire when blower speed is set at M1?
2. Do you have power at the Light Blue wire when blower speed is set st M2?
3. Does applying battery voltage to the terminal of the resistor at the yellow wire work the blower at low speed?
4. Did you test the HTR fuse ( 25A) in the fuse box?

I will copy this thread to the previous one and we will work from there.[/quote:0f3d9f4791]

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: "[email protected]"
Sent: Sun, January 17, 2010 1:56:14 AM
Subject: Topic Reply Notification - 1998 GMC Sierra heater blower resister

Nov 17, 2018 at 9:41 AM

[quote:fda5d37c28="KHLow2008"][quote:fda5d37c28="adubber"]Electrical problem
1998 GMC Sierra V8 Four Wheel Drive Automatic 115,00 miles

Hello again,

I am the guy with the gmc sierra i replaced the controll console for the haeter and air cond- I replaced the relay for the fan I replaces the air door actuator, I replaced the heater blower resister
you asked me to test the yellow wire going into the resister with the fan set on low and i did this finding no power. what next?

I am will to pay more for the advise if needed.[/quote:fda5d37c28]

[quote:fda5d37c28="KHLow2008"]Hi adubber,

You should have replied to your previuos post so that whoever was attanding to you can get notification and attend to you as soon as he gets online.

This would keep the history of what had transpired to allow an easier understanding of the problem and recommendations and repairs carried out.

Please do not edit the post as no notifications would be sent out.

Let me know the following.

With blower control speed at Low, you have no power supply to the yellow wire. Let ma know the following.
1. Do you have power at the Tan wire when blower speed is set at M1?
2. Do you have power at the Light Blue wire when blower speed is set st M2?
3. Does applying battery voltage to the terminal of the resistor at the yellow wire work the blower at low speed?
4. Did you test the HTR fuse ( 25A) in the fuse box?

I will copy this thread to the previous one and we will work from there.[/quote:fda5d37c28][/quote:fda5d37c28]

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: "[email protected]"
Sent: Sun, January 17, 2010 1:56:14 AM
Subject: Topic Reply Notification - 1998 GMC Sierra heater blower resister


Hello,

You are receiving this email because there is a reply to your question, "1998 GMC Sierra heater blower resister" at Auto Repair Car Questions.

To view and follow-up on the reply to your question, please click on the following link, https://www.2carpros.com/forum/viewtopic.php?p=772779#772779

Sincerely,

Bob, Ken and all of the 2CarPros team.

Nov 17, 2018 at 9:41 AM

[quote:f708383860="KHLow2008"][quote:f708383860="adubber"]Electrical problem
1998 GMC Sierra V8 Four Wheel Drive Automatic 115,00 miles

Hello again,

I am the guy with the gmc sierra i replaced the controll console for the haeter and air cond- I replaced the relay for the fan I replaces the air door actuator, I replaced the heater blower resister
you asked me to test the yellow wire going into the resister with the fan set on low and i did this finding no power. what next?

I am will to pay more for the advise if needed.[/quote:f708383860]

[quote:f708383860="KHLow2008"]Hi adubber,

You should have replied to your previuos post so that whoever was attanding to you can get notification and attend to you as soon as he gets online.

This would keep the history of what had transpired to allow an easier understanding of the problem and recommendations and repairs carried out.

Please do not edit the post as no notifications would be sent out.

Let me know the following.

With blower control speed at Low, you have no power supply to the yellow wire. Let ma know the following.
1. Do you have power at the Tan wire when blower speed is set at M1?
2. Do you have power at the Light Blue wire when blower speed is set st M2?
3. Does applying battery voltage to the terminal of the resistor at the yellow wire work the blower at low speed?
4. Did you test the HTR fuse ( 25A) in the fuse box?

I will copy this thread to the previous one and we will work from there.[/quote:f708383860][/quote:f708383860]

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: "[email protected]"
Sent: Sun, January 17, 2010 1:56:14 AM
Subject: Topic Reply Notification - 1998 GMC Sierra heater blower resister


Hello,

You are receiving this email because there is a reply to your question, "1998 GMC Sierra heater blower resister" at Auto Repair Car Questions.

To view and follow-up on the reply to your question, please click on the following link, https://www.2carpros.com/forum/viewtopic.php?p=772779#772779

Sincerely,

Bob, Ken and all of the 2CarPros team.

Nov 17, 2018 at 9:41 AM

Sorry for the delay in replying.

Just to be sure we are on the right track with the correct model, the circuit I have posted is for the 4.3 L engine. If it is not correct, please let me know.

From the last diagnosis, we are getting somewhere. You have a power supply fault and we are getting near to our destination.

The blower motor and resistor are perfectly good.

Power is not coming out of the HVAC control unit and you would need to test if power is available at the speed control switch. Test the brown wire for battery voltage with ignition switch turned ON.

If power is available and no voltage is available at the Yellow, Tan and Light Blue wire when speed is turned to low, M1 and M2 respectively, the control switch is faulty.

Ok,
I will do that and let you know

You did mention the switch earlier and i went to baxter and purchased one and installed it
this didn't help the issue.

You can test the switch for continuity according to the various speed mode.

Most important wire to test would be the power supply.

Was the switch replaced of the correct type?

Yes I have also relaced the hvac control unit on the dash

If you have power on the brown wire coming from the heater 25amp fuse when key is On and when you switch to low the yellow wire should have power-Is this happening if not were right back with HVAC control module. Now if yellow has power ,blower motor should come On-if not-check and test the ground pointG201 at right side of dash. Get back with us