| ID | Status | Date | Year | Make | Model | Transmission Type | A/C Controls | Public/Private |
|---|---|---|---|---|---|---|---|---|
| #12712 | Closed | 05 | Chevy | Trailblazer | public |
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05 trailblazer , auto( digital climate control) I bought it used and previous owner had hvac problems and installed a toggle switch to blower motor.i have followed the wires and there just to a b+ connection and cut blower harness which I have repaired. I have been testing to find the original source of the issue with no luck. All fuses are good, resistor harness isn’t burnt up or anything. I have b+ to the control head. No power at all to the resistor module. I can put 12v to the resistor b+wire and the blower will run but only on high. Changing the control head has no effect on the actual motor. |
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Lack of power on the red wire at the blower speed controller would likely be caused by a blown fuse in the underhood fuse box. It would be fuse #35 and marked as Blower. If that fuse is powered and good the next most likely cause would be a damaged terminal under the fuse box. The blower only running on high when adding power to the blower speed controller would indicate that the blower speed controller is faulty as well. This can be further confirmed be seeing if the blower continues to blow after the ignition is turned off. Your B+ jumper needs to stay in place during this test.
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The fuse in the underhood box originally was missing when I acquired the car. I got a fuse for it, installed it and still no power. The blower does continue to run when I turn the key off. In theory if that resistor is bad, I should be able to replace it, and that leave my blower motor jumper wired, working correctly and run by the control head? I will pull the fuse box out and check for a damaged terminal as soon as i can today and check back in |
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One thing i should add, I tested the control head powers and grounds. From what diagrams i have all the power is good, grounds also. My blower speed signal wire out of the gray connector on control head has no power with my jumper wire unhooked, with that jumper connected as I change the blower speed on the control head it varies from like 1-3 volts |
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Okay the “power” on the small purple wire is not really power but an unbiased or ungrounded control circuit. With the blower speed controller properly powered and grounded that signal should vary between 1 and 5 volts when the blower speed is adjusted. Yours seems to be doing close to that so I would say the blower speed controller is faulty. You should know that the three wire connector style that is currently in your truck is not longer available from a reliable supplier. Instead it has been updated by GM and ACDelco as part number 15-81773. I would strongly recommend locating and repairing the lack of power issue on the red wire before installing a new controller. |
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When I got out of work I did some tracing. Previous owner pulled the fuse in underhood box due to the blower running constantly on high , in all positions including key off. I reconnected the original harness installed the fuse and the blower runs , high constantly. I’m going to get a r3sistor tomorrow and throw that in and see how it works. |
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Installed a new resistor and harness today, works fine. I overlooked the obvious in the beginning with the missing fuse. Works as it should now though. On to fixing the cluster now. |
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What issues are you having with your cluster? Do you plan on fixing the cluster yourself? |