HVAC Issues
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HVAC Issues
So randomly today my blower quit working, check the fuses and fuse F2.28 was blown. The truck is a 2004 F250 SD with the 6.0. So i replaced the fuse clicked on to ac blew again. Every single setting except for off and dash vents blows the fuse. The blower motor does operate in all 4 speed positions. I replaced the blower motor resistor, blower relay as well as the selector switch in the dash. I also unplugged the blower and tried to utilize the switch still blew. I also already tried the electronic blend door actuator unplugging that as well still blew. Does anyone have any insight on what is going on?
Fleet Owner
Joined: Aug 2010
Posts: 21,255
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From: Reynoldsburg, Ohio
Could be the switch itself is the problem. I've had a few E-Series blower switches melt even though the blower motor and resistor were in great condition---no fuses blew but I had no fan operation either.
if it does turn out to be the switch consider replacing the pigtail lead at the same time---those too have been known to become heat affected after some years in operation.
FWIW I tend to run my blower in the middle or Medium speed.
if it does turn out to be the switch consider replacing the pigtail lead at the same time---those too have been known to become heat affected after some years in operation.
FWIW I tend to run my blower in the middle or Medium speed.
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New User
Joined: Oct 2019
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Could be the switch itself is the problem. I've had a few E-Series blower switches melt even though the blower motor and resistor were in great condition---no fuses blew but I had no fan operation either.
if it does turn out to be the switch consider replacing the pigtail lead at the same time---those too have been known to become heat affected after some years in operation.
FWIW I tend to run my blower in the middle or Medium speed.
if it does turn out to be the switch consider replacing the pigtail lead at the same time---those too have been known to become heat affected after some years in operation.
FWIW I tend to run my blower in the middle or Medium speed.
I already replaced the switch.
Hotshot
Joined: Jan 2004
Posts: 19,768
Likes: 1,082
From: St Louis
In addition to operating the blower relay and the blend door actuator, power from F28 is through the function selector switch (in all positions except OFF, VENT, & FLOOR) to the low pressure cycling switch then to the dual high pressure switch then back to the PCM to control the A/C compressor.
I suspect that eventually you'll find a chafed wiring harness, most likely under the hood. Inspect the wiring and connector those two switches and see if anything appears to be amiss. Check to see if a harness is rubbing on any of the idler pulleys or the like.
Unplug the low pressure cycling switch and see if the short goes away (will disable A/C cooling, of course, if it was operating at all). That will give you an idea where the fault lies, whether still "upstream" or "downstream" from that switch. Repeat, if necessary, for the high pressure switch. Report results.
I suspect that eventually you'll find a chafed wiring harness, most likely under the hood. Inspect the wiring and connector those two switches and see if anything appears to be amiss. Check to see if a harness is rubbing on any of the idler pulleys or the like.
Unplug the low pressure cycling switch and see if the short goes away (will disable A/C cooling, of course, if it was operating at all). That will give you an idea where the fault lies, whether still "upstream" or "downstream" from that switch. Repeat, if necessary, for the high pressure switch. Report results.
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