Timewalker

Yeah, I'm back. It's about my 2008 LS this time. Several months ago, my A/C started only blowing on High. Based on my 2011 blowing intermittently a few years ago, and the subsequent help here, I knew this was probably the resistor instead of the blower motor that I replaced in that one. So I ordered the resistor, crawled under the dash and replaced it. Huzzah! All speeds running again.
For a while.
A couple of weeks ago, it stopped blowing altogether.
My first thought was that the motor went out, but since it didn't give any warning like in the other car, I'm not so sure. No amount of banging on the glove compartment has made it start up again, like the 2011 would do.
So before I crawl under and cut all of that plastic out to remove the old one, what should I check/test to see if it is something else?
I have a digital multimeter, but I have only done basic electronic work (installing car stereos and amps, servicing my clothes dryer, etc.).

Thanks.

Oldblue

Have a look at the connection at the blower motor, is it melted or is it blackened from over heating?
is there power to that connection?

greg8453

What old blue says. If it has power and the ground is good your motor gave up the ghost without advanced notice. I'd fire that motor. LOL

donbrew

Well, you could put a jumper to ground. The Orange wire to the switch is the ground. The Brown wire comes from the relay #30 in the BCM and fuse #4 in the underhood fuse box. Backwards from what is usual.
My bet is the switch is worn out.

Timewalker

Hey guys. Thanks for the feedback. Sorry I disappeared, but first my dog got sick and then I caught a cold. However, today I did the pragmatic thing and bought a new blower motor, disconnected the old one, plugged the new one in in the floorboard and it started running right away. So now all I need to do is cut the dead sumb!tch out of there like I did in my 2011 and install the new one. As soon as I get decent weather on a day off.
Thanks again.

Oldblue

Thanks for the follow up, glad you got it figured out! Hope your dog is doing better!

Timewalker

FINALLY this week the weather cleared up enough and I had enough time to cut out the old blower and screw in the new one (ugh, I hate that part). I started it up and it blows great, on HIGH.
Ugh.
I bought a new resistor and pulled the old one out that I had replaced back in March or so. It was blackened.
Started it up and it blows great, on HIGH.
Ok, so what could be going on here?
Thoughts?
Thanks.

donbrew

If it blows only on high the resistor is bad or the switch contacts are all burned except high (pretty low probability). Or, some wires are crossed.
Has anyone messed with wires without looking at or understanding a wiring diagram?

Timewalker

Nobody has messed with the wires. I considered it at the beginning of the thread, then decided to test a new blower by just plugging it in before I started testing wires and circuits.
Can I test the resistor with a digital multimeter?

donbrew

If you want to.
The switch routes the orange wire to ground. On high it goes directly to ground, bypassing the resistor pack. The other speeds go through various value resistors. So, if it runs only on high the switch is not connecting to ground via the resistor pack, QED. Switch, wires, resistor pack.

Here is the important part, again, the M represents to motor.