Blower Motor, AC & Heat - Won;t work!

MAANONSEN

MEMBER
2003 FORD F-250
5.5L
V8
2WD
AUTOMATIC
151,000 MILES

Hi,

I have a Ford F250 SD 2wh. Drive, 5.4 Lt? Engine, Automatic Pickup. When I bought it this problem existed. I cannot get the Blower motor to run, for the AC or for Heat! It;s crazy. So far, I have replaced the blower motor & resistor, the control switch on the panel, and figuring there is nothing left, I cannot figure why it won't work? Oh, I also checked and swapped both fuses and resistors, (interior and engine compartment), but that did nothing either.

Someone mentioned something about this being a negative ground system and possibly a ground short, but I don't have a clue on how to go about checking all that. Is this something you Pro's can help me with? And, am I better off bringing this to a garage for better equipment to check it?

HELP!
Thanks,
Mark

4 Replies

JACOBANDNICKOLAS

MECHANIC
109,867 POSTS

Mark:
In this case, the best thing to do is go to the blower motor and check to see if there is power available there. If there is, there is a ground problem. If there isn't power, you need to start tracing the wiring backwards to see where you locate power. It isn't a fun thing to do, but at this point, I don't see another choice at this point.

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Wednesday, December 17th, 2014 AT 11:08 AM

MAANONSEN

MEMBER
3 POSTS

Yes, thank you! I did try checking power to the motor, but not sure if I did it right, it didn;t work out.

One thing I failed to mention is when I turn the switch off, and then turn it on again, I hear a "rummmm" noise for about 1/2 to 1 sec. But can;t figure out what it is, almost like the motor starts, then dies? Except, I had my son put his hand on the blower motor when I heard this (and it wasn't once, it does this pretty much every time), but he could not tell if it was the motor. I mentionit as it might help someone to figure this out with me.

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Wednesday, December 17th, 2014 AT 2:14 PM

JACOBANDNICKOLAS

MECHANIC
109,867 POSTS

It may be the fuel pump that you hear.

As far as the blower, go directly to the fuse and make sure there is power at both sides of the fuse.

Let me know what you find.

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Thursday, December 18th, 2014 AT 4:57 AM

MAANONSEN

MEMBER
3 POSTS

Steve,

You know, that is possible. I just assumed it was a mechanical pump, I'll check that out. Hum, but as I type this it doesn't happen when I turn the truck key to accy or turn it on, it only happens when I turn the blower knob/switch?

In any case, I will check the fuse panel and check both sides of the fuse and let you know, thanks!

Mark

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Thursday, December 18th, 2014 AT 6:39 AM