Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
Hello I will help you with your question,
Is this an automatic temperature control system?
Or do you have separate settings for the blower?
OK, that is the manual system.
There is logic in the control that sees the blower switch inn the off position and the compressor will not be turned on there but if you move to one of the speed settings the compressor should be turned on by the PCM IF all the conditions are met that allow compressor operation.
You should work on the blower operation first and then the AC operation.
Check the connector for the blower and the blower resistor. The can become burnt.
If you have a 12 volt test light I can help you check at the resistor for power in each position and see if the conditions are correct for the blower to operate.
Let me know if you want to test this
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Sure, if the connector is good let me know if you have or can get a 12 volt testlight. They are less than $5 at any big box or autoparts store.
Thanks and I will be here
Yes, that is the first check I would make. Place the meter leads on the motor connector pigtail from the resistor and see if there is battery voltage in the high blower position. If there is the motor has failed.
If no voltage check at the orange wire in the high position for voltage and the yellow wire in the #1 position,
If you have voltage there the blower resistor has failed and will need to be replaced.
You did check the 30 amp green HTR A/C fuse for power in the run position of the key?
Let me know what you find so I can help
If you are not on high speed with the switch try it and see if you can get up to 12 volts. I would do a direct current to the motor to check. You can use the red wire and the black wire for your sources.
The wire to the motor should be purple and black not red and black. The red wire is powered straight from the 40 amp BLWR fuse in the underhood fuse block so maybe you have a ground problem if you are only getting 9 volts between the red and black.
What do you get between the orange and black with the key in the run position and the blower switch on the high setting?
Then move the meter lead from the black wire to a good metal ground
Let me know what you get, if the voltage comes up when you go to a good ground you have a grounding issue for the black wire at the connector.
I will be here for about 40 more minutes tonight and back tomorrow if that will work for you.
I understand, you will not be charged again. You can always post to this thread and I will respond as soon as I see your post. No rush necessary except for your comfort.
I will be back on about 1:00pm EST as I need to get some sleep tonight.
If you have questions or results go ahead and post them, I check my questions when I get up so I can respond then and we can continue if necessary tomorrow when I get back online.
Let me know how i can help
OK, let me know what I can do to help you
Thanks for the update
Glad you found the problem, please let me know if you have further questions
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Let me know what I can do to help you
Glad to hear it and this is not uncommon. You should not have problems from here on out.
Please let me know if you have further questions
need help on a 1999 Chevy K3500 pickup with a 7.4 L