4.6L V8 Technical Discussions Any questions about engine, transmission, or gearing can be asked here!
Old Oct 22, 2015, 06:59 PM
How-Tos on this Topic
Last edit by: IB Advertising
See related guides and technical advice from our community experts:

Browse all: Ford Mustang Interior Guides
Print Wikipost

AC/Heater fan not working...

Thread Tools
 
Search this Thread
 
Old Aug 16, 2022 | 04:09 AM
  #21  
boecherer's Avatar
boecherer
 
Joined: Oct 2020
Posts: 5
From: CA
Default

Originally Posted by boecherer
Good to hear you got it working. I know my wipers work so it's not a fuse for me. The fact that I can jiggle the fuse box for my issues seems to indicate it's just a loose connection. Just yesterday I turned it on and it worked for 5 seconds and then probably from the bumps in the road, it turned off again. I'll be sure to update here once I check the fuse box connections.
I just saw a response to this post and saw what I wrote and that I would update this when I checked the fuse box connections. That was back in 2020 and since then I did check the fuse box. I disconnected it and took it apart a bit and found sone of the leads that mate with the relay for the blower motor were not making a connection. I was able to coerce them into making a better connection and the fan has been working ever since

It did get stuck on high (4) recently and that was due to the resistor module that goes bad and doesn't provide any resistance so all fan positions are stuck on high (no resistance). The funny thing was that I replaced that module with a replacement a while back trying to troubleshoot the blower issue and it turned out not to be the issue, but I left the replacement in since it was in and done. So when the fan got stuck on high recently, I knew what it was and I put in the original module that came with the car and that worked. Nice to have spare parts laying around and ones that are original and older than the replacement parts.
Old Aug 29, 2022 | 07:44 PM
  #22  
66mustangcoupe289's Avatar
66mustangcoupe289
 
Joined: Aug 2022
Posts: 3
From: north carolina
Default

i’m having the same issue, ive replaced the blower motor, blower motor resistor, ac clutch relay, blower motor fuse, im getting power to all the connection, sometimes it blows and works fine sometimes nothing blows at all im lost i dont know what else it could be other than ground or pcm issues
Old Aug 29, 2022 | 08:06 PM
  #23  
66mustangcoupe289's Avatar
66mustangcoupe289
 
Joined: Aug 2022
Posts: 3
From: north carolina
Default

also have a new power distribution box(fuse block/box) whatever you wsnt to call it
Old Aug 29, 2022 | 10:25 PM
  #24  
boecherer's Avatar
boecherer
 
Joined: Oct 2020
Posts: 5
From: CA
Default

Sorry to hear you're having so many problems after replacing just about everything. Someone above mentioned the actual fan switch (in the dash I assume) might be the problem. Have you tried replacing/checking that? Maybe you can bypass it to see if it stays on when not using the actual switch.

When it blows does it blow at the correct speed or only high speed? Since you've replaced the resistor it's probably not that since even if it went bad again, it would blow at full speed.
Old Aug 30, 2022 | 06:14 AM
  #25  
66mustangcoupe289's Avatar
66mustangcoupe289
 
Joined: Aug 2022
Posts: 3
From: north carolina
Default

yes when it blows everything works correctly, however it is more likely to cut off if keep touching the controls
Old Aug 31, 2022 | 05:15 AM
  #26  
boecherer's Avatar
boecherer
 
Joined: Oct 2020
Posts: 5
From: CA
Default

It sounds like it might be the switch. Someone mentioned above "I have helped with many blower problems and it tends to be the connector on the fan switch itself that cannot handle the fan/resistor currents without overheating and loosing all connections." if you haven't seen that. There is also a schematic: https://iihs.net/fsm/?d=40&f=Manual%...l%20System.pdf

I'm not a mechanic, but I've fixed a lot of things. I would try messing with the switch and continually switch it to see if it's reliable. From the info above, if the switch can't handle the fan currents without overheating, I assume that when the fan is on the highest speed, the most power is running through the switch.

And not knowing what the switch is like, maybe you can get it out and set something up to set it on speed 2 or 3 by bypassing the switch to see if it runs longer without the switch in the mix.
Old Sep 23, 2025 | 06:23 PM
  #27  
ecar67's Avatar
ecar67
 
Joined: Sep 2025
Posts: 2
Default AC/Heater fan not working

I just had this problem on 2007 gt replaced blower resister under dash didn’t work then I had to take passenger side floor panel off and bumped the wiring harness connector and the ac blower came on there is a big white connector that had a burnt pin connected and it melted that part of the connector went to the salvage and found a good connector bought a pin remover on Amazon $15 and marked and labeled wires and replaced the bad connector repaired wire worked great a word of advice to disconnect the connector it has a lever you have to pull on one side of the connector so pay attention
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
str8boostin
2005-2014 Mustangs
1
Sep 29, 2014 08:34 AM
mustang86
5.0L (1979-1995) Mustang
1
Apr 2, 2007 06:27 PM
gentlejax2
5.0L (1979-1995) Mustang
6
Sep 2, 2006 11:21 AM
rybro
General Tech
3
Jun 23, 2006 12:45 AM
2003 GT Mustang
4.6L (1996-2004 Modular) Mustang
4
Apr 9, 2006 05:17 AM




All times are GMT -5. The time now is 05:52 PM.