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Ok that's the control module by the blower motor or also known as resistor. I have no power on any of the wires that go to that what I need is the wire diagram for this in the pic. That blower switch is what had the wire spliced into it that ran to a random fuse on driver side fuse block
Ok that's the control module by the blower motor or also known as resistor. I have no power on any of the wires that go to that what I need is the wire diagram for this in the pic. That blower switch is what had the wire spliced into it that ran to a random fuse on driver side fuse block
The resistor (aka blower control module) is on the top left corner of the diagram, just to the right of the blower motor. Continuing down the left side from there, the next “box” is the ECM, then the next “box” below that is the HVAC Control Module which is what you posted a picture of. I know it doesn’t look like a module, but it is - an advanced scan tool can pull DTC’s, execute commands, and read live data from it like any other module on the data network.
The *****, levers and buttons you push are just inputs to the control module that tell it you are requesting a change in the HVAC settings. When you change the settings, the module determines the necessary steps to make it happen.
Originally Posted by Lowmanauto
Just curious can I just bypass that resistor and just wire the blower motor to a toggle switch?
Sure can, but it will only work on high speed.
Originally Posted by Lowmanauto
Also dont know if its related but the abs light came on at same time blower stopped working
It could be - I’ll have to do some digging and see if the ABS light and blower motor have a common feed.
Originally Posted by Lowmanauto
Actually yes do you have page 2? Cause the grey/black wire at the control head you said was for blower speed was the wire that was spliced into
As I said, all page 2 shows is the junction block and which wires splice together between the control head (under radio) and the resistor; but I’ll try to get it posted this weekend.
From the control panel, the gray/black wire (speed control) is supposed to change to the purple/white wire at the resistor. If this wire was cut or spliced into, remove whatever was done and repair the original wire - you may have to open the harness to find it.
The red wire at the resistor has a direct battery voltage feed (hot at all times) from the HVAC blower fuse in the underhood fuse box. You should be able to ground a test light at any point on the body (as long as its clean) and verify this. If the battery feed is good, jumper the test light between the red and black wire at the resistor connector (unplugged) to confirm the ground is also good.
Ok update. The 30 amp HVAC fuse in my driver side dash has no power on either side. I checked both terminals with fuse out and I found a diagram that says that 30 amp fuse goes directly to the blower speed switch on the control head under the radio. So I'm assuming that's why my blower is not working cause I have no power to the speed switch/****. Fuse is brand new, replaced just in case so what would cause no power to even the fuse?
Ok update. The 30 amp HVAC fuse in my driver side dash has no power on either side. I checked both terminals with fuse out and I found a diagram that says that 30 amp fuse goes directly to the blower speed switch on the control head under the radio. So I'm assuming that's why my blower is not working cause I have no power to the speed switch/****. Fuse is brand new, replaced just in case so what would cause no power to even the fuse?
Was this a diagram left by the person who spliced into the wiring?
From the factory, both HVAC fuses in the underhood fuse box get a direct battery feed - they are hot at all times. If there’s no power to the HVAC fuse(s) under the hood, there’s an open circuit between the battery and those fuses. Since the box has a primary cable feed from the battery, then the fuse box probably has a fault in it that’s keeping power from getting to those fuses, otherwise you’d be seeing other things that aren’t working.
If you really want the blower to work as intended, I’d recommend you start by first correcting the wiring under the dash. Remove the splices and verify with a meter that you have good continuity between the HVAC control panel and the blower resistor on the speed control circuit (Gray/black wire to purple/white wire). Once that’s established, use your meter to check continuity between the control panel, resistor, and their respective fuses under the hood. If you have good continuity, and there’s battery power getting to the fuse box, the fuse box needs to be replaced.
Ok so I have done some test my driver side interior fuse box in the dash is bad. It's the gmc 1500 classic does anybody know exactly witch box I need? Ebay said like 2002 to 2006 and 07 to 09 or 13 but none specific to the 07 sierra 1500 classic
