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Discussion Starter #1
I have a 2004 Grand Marquis A/C blower working only on high speed. I am thinking I have an open ground. Anyone that can tell me of known ground problems for the A/C blower? I replaced blower switch and resistor on firewall. I have manual A/C. I have power .going to wires at resistor, but no low or medium fan speeds. Any solutions would be greatly appreciated.
 

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I know you said you replaced the resistor but it would be a good idea to check it with a multimeter before trying anything else.



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Discussion Starter #3
I know you said you replaced the resistor but it would be a good idea to check it with a multimeter before trying anything else.


Thank you for your reply. I used the multimeter on my original resistor but the ohms were not within specs so I thought I would give it a try. I also checked it on the replacement resistor. I do not like replacing parts just to see if that will fix it......but I have been messing with this problem over a month now and it is driving me crazy. I am on a fixed income so dealership is out of the question.
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Was the new one out of spec too? The power and ground don’t change for the blower motor, just the resistance value. So I doubt the problem would be power or ground related.


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Discussion Starter #5 (Edited)
Problem is solved as suspected it was a ground issue. Someone spliced the wires going into the blower resistor. The number 3 pin in the connector is the ground for the resistor and that came loose.The high speed fan circuit doesn't go through the resistor and picks up a ground else where. I want to thank all who replied
 
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