Buick Repair Questions? Ask a Mechanic for Answers ASAP
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We need to check the four related fuses in the I/P fuse panel in the glove box area with a 12 volt bulb type (not led) to ground. Change the blower speed control while doing this. What we're looking for is the light to dim or even shut off when changing speeds.
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Replace the ignition switch.
There is a dedicated circuit in the ignition switch that often has high resistance and therefore blower speeds are lost on the lower speeds. When on high, the blower motor pulls it's amperage through a different fuse and not through the ignition switch. Replacing the switch should correct your concern.
We can continue to work on this. I've had numerous ignition switch failures cause a loss of amperage at the low blower fuse due to excessive resistance in the switch itself. Did you not say the test lamp shut off while probing the low blower fuse? That would indicate a loss of amperage at that circuit which comes directly from the ignition switch. I can only go by the information given. Did you replace the switch itself and check the connections? Can you do the same test at the c201 connector labeled 5 in the picture below?
and you disassembled the column and replaced the switch and harness labeled 1 in this picture?
i did the ignition switch,same problem,all this started after my son had a aftermarket radio installed.will this have anything to do with this problem
Again, have you done the same test at the connector mentioned above and at the ignition switch. Circuit 300 in the schematic above.
not yet it is very cold out side right now.should be warmer tomorrow.will check it then,what should i be looking for
The same thing with a test lamp. The light to dim when moving the blower control switch or a burnt terminal at the connector
backprobe the red wire at the same c201 connector and do the same test.
Study the schematic above with emphasis on the circuit labeled 300 (orange wire) and also the voltage feed to it before the ignition switch (red wire circuit 142). If you have a voltage drop which causes the light to dim, when in the mid blower speeds (and we know its not a blower motor problem because you said it works on high) Then the problem is either in one of those two circuits or the ignition switch.
ok there is power at the red wire,but there is no light on at the 300 circuit org wire
Circuit 142 supplies power to the ignition switch. Once again, with the ignition switch on and the blower set to mid speeds, If you have power at circuit 142 red wire at the c201 connector and none at the circuit 300 at the c201 connector than the loss if power can only be between the connector and the ignition switch or the ignition switch itself.
This isn't my first rodeo... :)
Glad you got to the bottom of it.