Cars & Trucks Logo

Related Topics:

A
Anonymous Posted on Aug 31, 2015

My 1998 gmc jimmy slt has a heating problem. The heater wont turn off. As long as the car is on the heater is on full blast. The fans work and everything knob wise works but the heater is always on.

1 Answer

Jeff Armer

Level 3:

An expert who has achieved level 3 by getting 1000 points

Superstar:

An expert that got 20 achievements.

All-Star:

An expert that got 10 achievements.

MVP:

An expert that got 5 achievements.

  • GMC Master 15,575 Answers
  • Posted on Aug 31, 2015
Jeff Armer
GMC Master
Level 3:

An expert who has achieved level 3 by getting 1000 points

Superstar:

An expert that got 20 achievements.

All-Star:

An expert that got 10 achievements.

MVP:

An expert that got 5 achievements.

Joined: Nov 22, 2012
Answers
15575
Questions
1
Helped
7105385
Points
73899

The air temperature valve electronic actuator positions the temperature door according to the temperature setting of the temperature control on the temperature control knob. For the full COLD temperature setting, the temperature control returns approximately 12 volts to the air temperature valve electric actuator. When the temperature setting is changed to full HOT, the temperature door is moved to the warm position and the output drops to about 0 volts. For a temperature setting in the mid range, the temperature door is positioned according to the voltage supplied through the temperature control switch.
Temperature Control Inoperative

2

Inspect the HVAC I fuse 21.
Is the fuse open?
--
Go to Step 20
Go to Step 3

3

  1. Disconnect the air temperature valve sensor.
  2. Turn the ignition switch to the RUN position.
  3. Move the headlamp switch to the PARK position.
  4. Using the J 35616-A , connect a J 39200 Digital Multimeter (DMM) between cavity 8 (CKT 733) of the air temperature valve motor connector and ground.
  5. Move the temperature control knob from the HOT position to the COLD position.
Does the voltage vary smoothly and continuously within the specified range?
0-12 V
Go to Step 4
Go to Step 9

4

Using the J 35616-A , connect a J 39200 DMM between cavity 10 (CKT 341) of the air temperature valve motor connector and ground.
Does the voltage equal the specified value?
B+
Go to Step 5
Go to Step 7

5

Using the J 35616-A , connect a J 39200 DMM between cavity 10 (CKT 341) and cavity 7 (CKT 1850) of the air temperature valve motor connector.
Does the voltage equal the specified value?
B+
Go to Step 6
Go to Step 8

6

Replace the air temperature valve motor.

5 Related Answers

Anonymous

  • 9 Answers
  • Posted on Dec 04, 2008

SOURCE: 94 GMC Jimmy heater fan not working

if you hear the fans blowing and no heat is coming
then you mite have to replace the heater.

before you try to replace the heater talk to Lords

Ad

Anonymous

  • 239 Answers
  • Posted on Jan 07, 2009

SOURCE: 2001 gmc jimmy defroster-heater blower will not direct heat

you have a vacuum leak

Anonymous

  • 73 Answers
  • Posted on Apr 15, 2009

SOURCE: 1998 GMC Jimmy-Turning Signal Noise

check all bulbs first

Anonymous

  • 1 Answer
  • Posted on Apr 22, 2009

SOURCE: 2001durango slt no heat in front

I have a 2001 Black Durango that had the same problem. There is a resister to the right of the ac/heat blower (underneath the dash on passaenger side). This needs to be replaced. You might want to replace the motor as well. Both are real easy. I had replaced the resister first and everthing worked fine for about 6 months and then my ac/heat would only works on high. I replaced the motor and now it works just fine. The resister was about $15 at dealership and the motor is prob around $40-$50. I hopes this helps. Good Luck!

Anonymous

  • 20 Answers
  • Posted on May 08, 2009

SOURCE: i have 2005 chevy trailblazer heater wont work,

Sounds like your water pump is going out or your thermostat is stuck. Check the thermostat first and make sure it is not frozen in the clsed position.

Ad

Add Your Answer

×

Uploading: 0%

my-video-file.mp4

Complete. Click "Add" to insert your video. Add

×

Loading...
Loading...

Related Questions:

0helpful
1answer

Heater only blows cold 1998 gmc jimmy

are both heater hose getting hot
0helpful
1answer

Temp. keeps going up and down between 180 and 210 also heat then no heat

Sounds like it is low on Antifreeze or the thermostat is hanging up. This would account for the lack of heat, which should be felt in the water lines coming out of the heater core.

Both water hoses should be equally hot if the heater is on full blast. But there is a radiator cooling fan for the engine and it is to some degree responsibile for cooling the water. But even at 180, you would have heat.

Last, as this is 13 years old, check for collapsing main radiator hoses.
0helpful
2answers
0helpful
1answer

1998 GMC Jimmy SLT warm air only from heating ducts

if you claim that your heater core is flushed properly then my bet is the temp regulator is bad.
2helpful
1answer

94 GMC Jimmy heater fan not working

if you hear the fans blowing and no heat is coming
then you mite have to replace the heater.

before you try to replace the heater talk to Lords
7helpful
3answers

2000 GMC Heater Problem

I had problems with a similar truck,a 1998 GMC diesel after checking to make sure the control cables were operating the blend door and blowing the mess of the heater core,I replace the thermostats.Still no heat turns out there was a small amount of debris collecting in the fitting for the inlet hose at the thermostat housing after removing it and blowing out the lines the heat was fine.
4helpful
3answers

1998 Jimmy SLT heater problem

if the blend air door keeps cycling even if the setting is hot or cold this tells you that the thermostatic control sensor is bad. replace that and the problem will be solved.......please rate this.
Not finding what you are looking for?

338 views

Ask a Question

Usually answered in minutes!

Top GMC Experts

ZJ Limited
ZJ Limited

Level 3 Expert

17989 Answers

Ronny Bennett Sr.
Ronny Bennett Sr.

Level 3 Expert

6988 Answers

john h

Level 3 Expert

29494 Answers

Are you a GMC Expert? Answer questions, earn points and help others

Answer questions

Manuals & User Guides

Loading...