AC Fan blower quit working on high

[totalpackage]

This morning at 27 degrees my blower did not work at all. Then after switching it from low/med/high and turning on and off the controls, it came on but the high speed setting did not work. I assume that its the blower motor resister that needs replacement. Any one think of anything else?...dont know if this matters but the low speed has always been wimpy throughout the years..

 

[PG01]

Just high?... when its resistor it’s usually low and med/high... id do resistor, blower motor and clean out the box, youd be surprised how much more air movement youll get. Maybe even switch if you turned off and on and it worked...

 

[totalpackage]

I cleaned the box a year ago trying to get more air movement. Not much trash was in it. I didnt see a difference unfortunately. What switch are you talking about? on the main controls? Also this is a 2 door 96 model.

 

[PG01]

Yes, main switch. But rereading your original post and seeing that low was always weak your blower motor seems like its shot. If you’re going to do resistor, i would do motor also, if motor is on its way out it will take new resistor with it.

 

[1BADI5]

The blowers in the GMT400s in general suck.

Last fall I clean out the box and dropped in a new blower motor, not sure the over all effort was worth it, but its done

 

[totalpackage]

ok, so i did go ahead and replace the resistor and the motor...both original 21 year old parts. I noticed when rolling the new fan and old fan that the new one moved with much less resistance. It did not fix my high speed issue but fill better knowing the blower is likely faster and pulls less current hopefully. So the issue could be the blower relay (which looked healthy and i hit it with WD40 for the heck of it as i also did with all my connections. Or its likely the ac controller which i already ordered...to be continued.

I would like to add i have had extensive ac issues in the past. Getting cold that is. When the ac is on, the compressor cycles on for about 10 sec and then off for a bit, then back on. I posted all that in an earlier post but didnt get conformation if that was normal...if not,maybe this controller has been my gremlin?

 

[dubyagee01]

Sounds like your evaporator is clogged with dirt. Have a friend with an endoscopic camera?

As far as high speed. Check the relay output with a meter.

 

[totalpackage]

..I also failed to mention i vacuumed and washed out that air box. 2nd time in 3 years and wasnt to bad. I just replaced ac controller which was original and practically fell apert in my hand. Clips broke and plastic was yellow from age. i took a pic of both old and new. There was a large piece of tape over old ones circuit board which hand all the sticky gunk melted within the board and other components. It works more sound than the other one. Also replaced ac blower relay and the high fan setting still does not work. So EVERYTHING except the harnesses have been replaced. Any ideas? Whats the output pins on the harness? I cant belive i have changed the blower resistor, motor, relay and ac control and the high output does not work!! UGH!!!

 

[totalpackage]

....continuing on. I found and verified the blower fuse under the hood is good. Found this diagram and following it. As you can tell the high fan setting does NOT go thru the blower resistor.

 

[retiredsparky]

The drawing is not correct. Even engineers can make mistakes! The blower motor wire labeled PPL for purple color should be wired to the common terminal of the relay (where the dark blue wire is connected).

The dark blue wire then connects where the purple wire is currently connected.

That is why you have no high blower speed.

Larry