2007 XLT - Blower Motor Slight Tick like it's trying to turn on. Sometimes it will most time it wont

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

Jtruck

New Member
Joined
Nov 18, 2009
Posts
3
Reaction score
0
Location
Normal, IL
Hello,
2007 Expedition XLT with manual hvac. I know this crazy, but i've replaced all of this and the blower still will only work every so often. I live in AZ so it would be nice if it worked consistently (I don't care even if on high).
- blower control module (motorcraft) that fits behind the 1-4 setting on the head head unit.
- ebay hvac control head unit. i'm getting voltage out of the 4 pins of the connector.
- blower control wiring harness
- blower motor (autozone)
- about 4 different blower motor resistors (including motorcraft)
- blower motor resistor wiring harness (dorman)

When I turn on the truck, I can hear/feel a slight tick on the blower motor like it is trying to start up. I had the blower motor resistor wiring harness off and after I gave it a good whack (like i've read in other forums) it started up but only for about one minute on full blast. Didn't realize it didn't need the blower motor resistor not connected but I guess it makes sense as that controls the speed of it. Another odd thing is that when it came back on the air only blew out of the defrost vents, when it switched it over to main vents it didn't change.

I am plumb out of ideas. I've literally read every thread on this forum that has to do with blower motor...I'm willing to try anything you all suggest.

Jtruck
 

Trainmaster

Old School Member
Joined
Jun 17, 2017
Posts
3,392
Reaction score
1,919
Location
Rockaway Beach, NY
Get your hands on a wiring diagram and start checking for voltage at specific points. The common problem is the resistor and the wiring and plug that go to the resistor. The crimped connnectors to the wires degrade/melt or corrode.

I've also had some problems with the controllers, which contain electronics. Sometimes the used ones are bad.

Check each component separately using a test light, meter or jumper and a power source. That's the only way to troubleshoot. When you randomly replace parts you run the risk of installing something new that doesn't work and doubling your problems.
 
OP
OP
J

Jtruck

New Member
Joined
Nov 18, 2009
Posts
3
Reaction score
0
Location
Normal, IL
For the life of me, I cannot find a manual a/c wiring diagram anywhere. Bought a test light and I'm getting an ever so slight light for just a brief second every 10 seconds or so on the wiring harness going into the blower. Clearly not enough to power it up. it's like something is trying to send it power but it's not enough. Tested the hvac related 15/37 position fuses and they were fine. Swapped the relay in position 1 under the hood fuse box. Got a 3rd controller from junk yard and it didn't do the trick.
Gotta be a crimped connector like you suggested. Just unsure how to test it all. Been thinking about getting one of those power probes you see all over youtube for diagnostics.
 
Top