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2004 Silverado 1500 4WD Crew cab 5.3L
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Discussion Starter · #1 ·
The other day I took my truck to a drive through carwash. There was a little water that came through the passenger side and driving home the AC blower was fluctuating between not blowing at all to blowing normally. I figured a connection got water in it and after it dried out, it would work normally. the next day the AC blower didn't come on at all. My resistor is good, the fuses and relays are good, the blower motor is good, I swapped it with another one I had. The climate control panel indication shows fan speed moving up and down when I change it but blower isn't running. I also noticed that the AC compressor isn't coming on. Is there anything else to check before changing out the climate control module?
 

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did you put voltage on the blower motor ?
I do not go to a carwash ....shutdown the HVAC when you got to the carwash..water will suck into the air system.
 

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Discussion Starter · #3 ·
I've got 12.25 volts at the resistor with truck off and 14.2 running. Same at the blower motor.continuity for both motors check good, 0.00, windings are good,I mistakenly said my compressor wasn't cycling, but it is, so it's just a blower motor problem. I don't see how the new motor and old motor are bad with the windings good. Thanks for the tip about shutting down AC going through car wash. In Vegas, it's pretty much on non stop 9 months out of the year, I don't even think about turning it off.:unsure:
 

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gm trucks 2004-5 had many blower motor resistors/connector to the components in the blower /resistor area...
some had fires ...
 

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Fix, do you have the manual temp, or the auto temp HVAC?
The manual has 2 fuses the auto has one.
The manual uses a speed assembly that has 1 relay and a bunch of speed resistors.
The auto uses a transistor to control speed.
 

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2004 Silverado 1500 4WD Crew cab 5.3L
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Discussion Starter · #6 ·
I have the auto temp dual zone
 

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Discussion Starter · #8 ·
I saw one 30A fuse in the interior fues block on drivers side and one 10A in the engine compartment fuse box. Both fuses were good. The Blue wire running to the motor has 12.3V when checked with a door bolt as ground and also when checked with it's black wire mate that runs to the motor. Electrically everything seems like the motor should run.o_O
 

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I don't have the wire colours; but we'll assume the blue is the power to the motor.
I'll also assume the motor housing is plastic and that there is a ground wire.
The black would be that ground wire.
Your testing description proves the ground is good, I believe.
The transistor I talked about is the speed control.
If you change the fan speed settings, does the 12 volts change on the blue wire?
2nd test, if you take the motor out of truck and wire two leads to it and hold those wires to the battery posts, will the motor run?
 

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2004 Silverado 1500 4WD Crew cab 5.3L
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Discussion Starter · #10 ·
Funny, I just wired the motors, both of them to the battery direct and they both ran. So I thought why won't they run when plugged in. I rechecked the wires and now zero Voltage going to the motor plug, and Zero voltage feeding the blower motor resistor. I had voltage there yesterday. The problem I was having was that after the car wash the fan was cutting in and out like it was getting voltage and then voltage was removed, like a loose wire. It still doesn't explain why the motors weren't running when they had voltage. I was thinking that I had a bad plug to the motor because I was piercing the wires with my needle probes so not really checking the plug. After the motors ran connected to the battery I was going to check the plug when I found no voltage at all this time. Something tells me this is going to be fun tracking down.
 

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The speed control assembly should plug in as well.
And you should have 12 volts on one of the wires feeding the speed assembly.

I have a schematic for the GMC Envoy, the 12v feed is red in the Envoy wiring.
The red wire is fused from under the hood, labeled Blower fuse
 

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Discussion Starter · #12 ·
By speed control assembly do you mean the Resistor assembly? If so, I did check the red wire going to it and zero volts which makes be think it's possibly the climate control unit. I'm going to check it out tomorrow. I think there are a couple of wire harness plugs that plug into the back of it. I'll post my results. I appreciate the help.
 

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Fix, it's a resistor assembly when you have the manual controls, you need to physically change the speed with your fingers.
The auto system, set and forget, uses a transistor (a big field effect transistor) to let the system automatically change the blower speed.
You said you had the auto system.
The red wire is the power wire and it goes to a fuse, an always hot fuse.
 

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do you have an automatic HVAC controller system . the blower motor has the HVAC 30amp fuse going to the red wire blower , the black wire is ground and the controller feed in is gray/black changes the resistance/speed ... then the blower logic controller changes the blower motor speed .the gray/white wire logic in side of the blower motor , goes to the controller ..changes the ground resistance of the blower motor gray/white wire ,,
 

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Discussion Starter · #15 ·
Fix, it's a resistor assembly when you have the manual controls, you need to physically change the speed with your fingers.
The auto system, set and forget, uses a transistor (a big field effect transistor) to let the system automatically change the blower speed.
You said you had the auto system.
The red wire is the power wire and it goes to a fuse, an always hot fuse.
I have the auto temp control I believe. I turn the knobs and dial in a temperature on either drivers or passenger side
 

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Discussion Starter · #16 ·
do you have an automatic HVAC controller system . the blower motor has the HVAC 30amp fuse going to the red wire blower , the black wire is ground and the controller feed in is gray/black changes the resistance/speed ... then the blower logic controller changes the blower motor speed .the gray/white wire logic in side of the blower motor , goes to the controller ..changes the ground resistance of the blower motor gray/white wire ,,
I think I have the Auto controller where you dial in a specified temperature from a low of 60 to what ever the high temp is. I've never dialed in a max temp so I don't know what it is. In the winter it's set on around 74 to 78 usually.
 

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I have the auto temp control I believe. I turn the knobs and dial in a temperature on either drivers or passenger side
Sounds like you do fix, I'd look for a blown fuse.

Or, the other possibility is water got into the fuse panel and caused some shorts, or corrosion.

Edit.

Just reread your first post, you say the AC compressor doesn't work either.
I'd be suspicious of a wet fuse panel.
 

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Discussion Starter · #18 ·
Sounds like you do fix, I'd look for a blown fuse.

Or, the other possibility is water got into the fuse panel and caused some shorts, or corrosion.

Edit.

Just reread your first post, you say the AC compressor doesn't work either.
I'd be suspicious of a wet fuse panel.
All the fuses are good and Compressor is coming on, I was mistaken on that, so only issue is no voltage to the resistor that feeds the blower and no voltage to the motor. Yesterday I had voltage at both points. My blower fuse is a 40A. The climate control unit appears to be working correctly, fan speed changes on the led indication and all other buttons seem to work fine. Tomorrow I'm going to pull the control unit and check the feed wire that goes to the resistor. Maybe I have a faulty control unit. The image is the resistor I have that goes to the blower and the other is the control unit even though it's not a very clear picture




Musical instrument accessory Audio equipment Rectangle Font Compact cassette
Circuit component Font Auto part Electronic device Audio equipment
 

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Discussion Starter · #19 ·
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Does anyone know where I can find the pin out diagrams for this climate control. I have a 12way plug and a 24 way plug. 04 silverado 1500 LT 4WD Crew cab 5.3L gas
 

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Fix, your over thinking this problem.
It worked until it got wet.
The 12 pin plug to a 24 pin connector worked before it got wet.
If it looks fine, put back together before you have numerous problems and you won't get it fixed.

The red wire that has no voltage is supposed to be a fused 12 volt always hot wire, that's where your problem is, figure out why the 12 volts has disappeared.
 
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