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2005 Tahoe - Climate Control Question

mxmike#25

By mxmike#25
in Ask A GM Technician

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mxmike#25 New Member

mxmike#25

Posted
Posted

Sorry if I'm in the wrong spot to ask this question!

 

And apologies for posting this in New forum as well.

 

I've been a Chevy guy since I was a kid, but I've had my frustrations lately with the last 3 I've owned. But for now, can someone please direct me to a link/discussion about

 

2005 Tahoe LT - 2wd

 

I have two problems I need help with:

 

1) The AC blower for auto climate control. It shuts off, comes on with "auto", etc... It's a crazy problem. I had our neighbor help and he said it might be the blower resistors, as they go bad all the time. He disconnected it several times thinking the connection was bad. It began to work again, but not really. You could increase the fan speed SLOWLY, and it would work. But, if you tried to increase the fan speed too quickly, it would just blow at a medium speed.

 

2) Power seat - maybe one motor is burned out? The up/down selector switch is opposite! crazy. And the power memory setting never works, I think because one of the motors is not working. Andy ideas? fuse, breaker, etc.?

 

BTW, I replaced the battery a month ago or so. I'm not sure if that did something

bill190 Enthusiast

bill190

Posted
Posted

Did these problems start with the battery change and everything was working fine before?

 

In any event, you have a lot of computer modules which control things. Computers don't like low voltage!

 

So first thing to check is voltage.

 

Turn on the ignition (don't start), then check the voltage at the battery with a multimeter. It should be 12 something volts. Then start the vehicle and it should be 13/14 volts at the battery. This is the alternator kicking in and charging the battery.

 

Also check the voltages inside the vehicle. Like from one side of a fuse to ground. Or from the center connection on a cigarette lighter to ground. These voltages should be pretty much the same as the battery. Test the inside voltages with things turned on. A/C, radio, etc.

 

What we are looking for here is that in general the computers inside the vehicle are getting full voltage. If you are getting 13/14 volts at the battery and 9 volts inside, then there is a connection problem somewhere and your computers will not be happy! :)

 

If that checks ok, also be sure there are clean tight connections to the battery and to the main electrical wires. This is + to the battery and where that + cable goes. And - to the battery and where that cable goes. Also there would be a main - (ground) wire to the engine block.

 

As vehicles use more and more electricity, these main connections become *critical*! You should not be able to "wiggle" any screwed down connections.

 

Next disconnect the negative battery terminal and check all fuses. Look in your owner's manual for locations of all fuses. Pull one out at a time and check with an ohm meter.

How to check fuses...

http://www.dinosaurelectronics.com/Test_Fuse.htm

 

Checking all the fuses is doing several things here. We are "rebooting" all the computers by disconnecting the negative battery terminal, allowing time for any residual electricity to drain from all electronic modules, being sure all electronic modules in the vehicle have good fuses (there can be 25 or more computers in a vehicle these days), and we are being sure each fuse is firmly placed back in its socket providing a good electrical connection.

 

Then next reconnect the battery. Then turn the ignition switch on and wait about 30 seconds. (Don't touch any switches on the vehicle.) Then start the vehicle and again don't touch any switches for about 30 seconds. (This allows time for certain things to "calibrate" after having the power removed/restored.)

 

Then see if the A/C and seat are working as they should or not.

 

If not, about all you can do with the A/C is see that there are good electrical connections to everything. I don't see a bower resistor for this, rather there is a "blower motor control processor" which controls the motor speed and this is based on a pulsed signal from the "HVAC control module".

 

And with the seat, use a mirror/flashlight and look under the seat and see if there are any loose wires. Be sure all connectors are firmly plugged in.

 

Other than the above, further testing would require a GM Factory Service Manual set which you can order from helminc.com or a GM dealer.

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