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Hvac Problem: Stuck On Hot Air

Woodcutter

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Woodcutter Enthusiast

Woodcutter

Posted
Posted

This morning after using the defroster, I could not switch from hot air to cold. I tried switching from defrost to floor, bi-level etc. Then I tried switching from outside air to recirculate. Even turning the A/C on didn't do any good.

 

After letting the truck sit for about 5 hours, I jumped in and was getting all cold air again. Has anyone else experienced this?

 

This is the third time since I've had the truck that it's done this. When I took my truck to the dealer for a new rear main seal a month ago, I explained the problem but got the old "we tested it but found no problems" story.

 

Any info from you guys before I return to the dealer :banghead: would be great!!

j.roffel Senior Enthusiast

j.roffel

Posted
Posted

I know with the 99 if the hvac controls are disconnected then it blows hot air out the defrost, but you can still adjust the fan, cause its a seperate relay. So maybe your HVAC control plug is loose in the back?

 

Good luck

Woodcutter Enthusiast

Woodcutter

Posted
  • Author
Posted
I know with the 99 if the hvac controls are disconnected then it blows hot air out the defrost, but you can still adjust the fan, cause its a seperate relay. So maybe your HVAC control plug is loose in the back?

 

Good luck

 

So I assume the dash with have to come out to check this?

mini1 Enthusiast

mini1

Posted
Posted
Don't expect perfection out the bargain basement model :banghead:

 

So your SLE has a super-duper upgraded duluxe heater?

 

 

Yes it does. It works when I need it.

slomo007 Enthusiast

slomo007

Posted
Posted
Don't expect perfection out the bargain basement model :banghead:

 

So your SLE has a super-duper upgraded duluxe heater?

 

 

Yes it does. It works when I need it.

 

Show some respect man....not everyone needs a loaded truck. Just the fact that a work truck has the climate controlled option in it surprises me actually.

jrrod2004 Senior Enthusiast

jrrod2004

Posted
Posted

Sounds like you have this problem, if you want me to check your specific vehicle, PM my your VIN number.

 

 

 

 

Document ID# 2023311

2007 Chevrolet Silverado - 4WD

 

EI07264 - Manual HVAC Performance, Temperature, Mode, A/C Does Not Cool, DTC B0228, B0413, B0423, B0433, B3779, B3782 (Engineering Information) #07-01-38-009A - (10/02/20070)

 

 

 

Models:2007-2008 Chevrolet Silverado

 

 

2007-2008 GMC Sierra

 

 

Extended and Crew Cab Models Only with Manual Temperature Control HVAC System (RPO C67)

 

 

 

 

 

 

Attention: Proceed with this bulletin ONLY if the customer has commented about this concern AND the EI number is listed in GMVIS. If the customer has not commented about this condition or the EI does not show in GMVIS, disregard the bulletin and proceed with diagnostics found in published Service Information. THIS IS NOT A RECALL -- refer to Service Bulletin 04-00-89-053A for more details on the use of Engineering Information bulletins.

 

 

 

This bulletin is being revised to update the diagnostics. Please discard Corporate Bulletin Number 07-01-38-009 (Section 01 -- HVAC).

 

Condition

 

 

Important:

• This concern only applies to Extended or Crew cab vehicles.

 

 

• If the customer did not bring their vehicle in for this concern, do no proceed with this bulletin.

 

 

Some customers may comment that the A/C blows hot air or is inoperative. They may also comment that they are unable to change the temperature or HVAC mode of the vehicle. In this instance, the actuator door defaults to full hot and defrost position.

 

 

Cause

GM Engineering is seeing an increase in HVAC control head and actuator warranty where the root cause is intermittent wiring connections at the actuator, control head or the right hand BEC.

 

GM has a need to obtain information BEFORE any repairs are made. If the customer's concern can be duplicated, perform the following inspections/steps:


  1. <LI type=1>Note the following information on the repair order:

1.1. Describe the customer's concern -- be specific.

 

 

1.2. List any/all DTCs and note whether the DTC is current or stored in history.

 

 

1.3. Note Door position (feedback) counts from the Tech2.

 

Important: The concern must be current before diagnosis can be performed.
 
<LI type=1>Review and print the following SI documents -- Electrical Center Identification Views, for use during diagnosis:

• Junction Block -- Right I/P, Top View

 

 

• Junction Block -- Right I/P X4

 

 

• Junction Block -- Right I/P X5

 

<LI type=1>Locate the Junction Block -- Right Side I/P on the vehicle. <LI type=1>For the appropriate actuator, measure the following signals for voltage/resistance from the BACK of the X4 or X5 connector and record the following: Important: DO NOT unplug the X4/X5 connector.
 
Turn Ignition On, A/C Blower Full, if possible -- mode on "panel" and Temp to "cold."
 
 
 
Actuator will stay in default position until commanded to a new position. Change commanded position regularly to see if issue is still current.
 
 
 
Continue to monitor door positions (feedback) on Tech2 to see if it changes during circuit testing.
 

 

• Ignition Voltage -- 12V

 

 

• Door Control Signal -- 2.5V when stationary, 0V when commanded toward "cold" or "panel", 5V when commanded toward "hot" or "defrost"

 

 

• Low Reference -- less than 40ohms

 

 

• Door Position Signal -- measure voltage

 

 

• 5 Volt Reference -- 5V

 

<LI type=1>If any signals do not display the correct value or if the issue is corrected during testing, pull the connector and check the terminal for poor tension (use the appropriate terminal tool). Replace or repair the terminal if poor tension is found. <LI type=1>If all signals are correct and the issue is still current, locate the appropriate actuator and check the signal performance at the BACK of the actuator connector.

Contact engineer Adam Freeman at 586-914-0404 and provide him with repair order information. If necessary, Adam will provide information to proceed with correcting the customer's concern. If the engineer is not available to take the call, leave the following information: - Technician Name, date and time of call
 
- Dealer Name, Dealer Code & Phone #
 
- VIN and Repair Order #
 
Important: If the engineer does not return the call within one (1) hour, continue to diagnose and repair following the information found in SI. Fax the front and back of the repair order to Adam Freeman (fax #: 248-685-4196).

<A href="http://service.gm.com/servlets/BlobShtml?ShtmlFile=2023311&psdid=1647&evc=sm#ss3-2023311">

Warranty Information

For vehicles repaired under Engineering direction, use:

 

Labor Operation

 

Description

 

Labor Time

 

D9719*

 

HVAC - Engineering Information

 

0.5 hr

 

Add

 

To Replace Temperature Actuator

 

2.3 hrs

 

Add

 

To Replace Mode Actuator

 

0.5 hr

 

Add

 

To Replace Recirc Actuator

 

1.0 hr

 

* This labor operation number is for bulletin use only. This number will not be published in the Labor Time Guide.

 

 

 

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

999999994.gifWE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

© Copyright General Motors Corporation. All Rights Reserved.

 

 

cmf21 Enthusiast

cmf21

Posted
Posted

I sometimes have a hvac problem as well. When I have the heater on it'll quit blowing hot air and start to blow out cool air. Strange.

jrrod2004 Senior Enthusiast

jrrod2004

Posted
Posted
Thanks a bunch for the info!!! The service bulletin describes my problem.

M. Cueva I sent you a PM.

 

No problem, I replied to your PM, get that fixed, you paid for the warranty, now it is time for GM to pay.

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