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sprinkles08
sprinkles08, ASE Certified Technician
Category: Chevy
Satisfied Customers: 23114
Experience:  ASE Master and Advanced level certified. Factory trained with 17 years dealership experience
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2011 Chevrolet suburban Air conditioning fan will not kick

Customer Question

2011 Chevrolet suburban Air conditioning hi fan will not kick on.
Submitted: 1 year ago.
Category: Chevy
Expert:  K. Wiggins replied 1 year ago.

Hello, does it have auto climate control?

Customer: replied 1 year ago.
it does
Customer: replied 1 year ago.
The fan works when I manually set the relay. Also I have 2 powers 1 ground and a low voltage at the relay connection. Don't know if that helps any
Expert:  Gary replied 1 year ago.

I am sorry for the long wait

which relay are you setting or testing at ?

Customer: replied 1 year ago.
Top left of you are standing behind the driver side fender
Expert:  Gary replied 1 year ago.

which relay ? what is it called ?

Customer: replied 1 year ago.
Hi fan relay
Expert:  Gary replied 1 year ago.

that relay when the fan should be on high should show 2 powers and 1 good ground then the last terminal only showing a ground when the fan should be on high speed

Customer: replied 1 year ago.
I found 2 powers 1 ground and a low voltage.
Expert:  Gary replied 1 year ago.

the ground will it come and go when the fan should be on high then off high speed ? or stay the same low voltage all the time ?

will the ground come and go when its off high speed then on high speed?

Customer: replied 1 year ago.
Sorry but I am a little confused
Expert:  Gary replied 1 year ago.

the leg with low voltage is our problem but we need to find out of that is supposed to be the ground all the time or the ground that the computer is supposed to turn on and off to turn the high relay on

Customer: replied 1 year ago.
I did a continuity test to the ground from the computer (thick black with white stripe) to the ground post on the block. All was good.
Expert:  sprinkles08 replied 1 year ago.

Hello and welcome to JustAnswer!

I'm not 100% sure what you're testing. You mentioned having automatic temperature control, in which case the blower motor is supplied power and ground by the blower motor controller based on a signal from the control head.

Can you post the VIN?

Do you truly have automatic temperature control or is it a manual system?

You mentioned 'air conditioning high fan' which I take to mean the blower motor. Are you dealing with a blower motor issue or the engine cooling fan?

Customer: replied 1 year ago.
Engine cooling fan
Expert:  sprinkles08 replied 1 year ago.

What actual symptoms are you trying to repair?

Customer: replied 1 year ago.
The hi fan won't turn on. With manifold gauges the red side pins and the high pressure relief valves opens. Once I manually set the relay the fan kicks on and the Ac works 100%
Expert:  sprinkles08 replied 1 year ago.

Do you have a scan tool to monitor data?

Customer: replied 1 year ago.
No sir.
Customer: replied 1 year ago.
When I apply a ground to the low voltage it trips the hi fan.
Customer: replied 1 year ago.
What sends the ground signal to the relay?
Expert:  sprinkles08 replied 1 year ago.

The engine controller turns the relay on when a/c high side pressure is high enough. You need to be able to monitor high side pressure and/or perform a relay actuator test to see if the driver is functional or if the fan isn't being commanded on.

Customer: replied 1 year ago.
Is there a cheap counter I can get to do that?
Expert:  sprinkles08 replied 1 year ago.

An entry level scan tool starts at about $2,000. If you aren't able to borrow one you may be able to rent one at a big chain parts store such as Autozone. Otherwise you can resort to replacing parts in hopes that takes care of it or allow a shop to diagnose the problem and then repair it yourself, which would most likely be .5 o 1 hour of labor.

Customer: replied 1 year ago.
Let me see what type of computer I can get. I will keep you posted.
Expert:  sprinkles08 replied 1 year ago.

Great!

Customer: replied 1 year ago.
I'm going to grab a computer from my corporate mechanical facility.
Expert:  sprinkles08 replied 1 year ago.
Great!
Customer: replied 1 year ago.
here is he update. I can't get my hands on the computer like I thought I could. I am trying to see if I could get one but j think I might just have to take it to the dealer.
Expert:  sprinkles08 replied 1 year ago.

You may be able to have a dealer diagnose it for .5 to 1 hour of labor and then do the work yourself.