2003 Sub HVAC Fan speeds 1-4 not working , 5 works ok....

[calsdad]

Just noticed this afternoon on my drive home from work that it seemed like I wasn't getting any airflow from front (dash) vents on my 2003 Suburban 2500. When I turned the fan speed knob to 5 - the fan seemed to be blowing at it's expected speed.

 

When I got home - I tried putting a piece of paper in front of one of the dash vents to see if there was any airflow at all - and there seems to be nothing on speeds 0 -> 4. Speed 5 on the dial seems to work fine.

 

Any ideas why some speeds would not work and speed 5 is still working?

 

 

[Chris]

Blower motor resistor

[Doug_Scott]

+1

the most common part failure on GM trucks for a very long time. If you want to see how common, take a look at youtube and search for "blower motor resistor gm". Lots of hits that will help guide you through replacement.

[Chris]

I just had to replace one on a Buick Rainier. Same one as the trucks i believe. The part came with instructions for both GMT-800 and GMT-360. When it went out in my truck, i had speeds 1-4, but not 5.

[calsdad]

Thanks for the help. Looking on www.rockauto.com right now for a replacement - looks like there's a number of different options. At least it's a quick fix.

[Jsdirt]

Yep - every GM I've owned built after '88 has needed one at some point. The newer ones (late 90's to mid '00's) seem to fail much sooner.

[calsdad]

+1

the most common part failure on GM trucks for a very long time. If you want to see how common, take a look at youtube and search for "blower motor resistor gm". Lots of hits that will help guide you through replacement.

 

 

Found a few videos - looks very easy and quick to replace. Rockauto had the correct one listed for my truck - which has the auxilary rear heat and rear AC. Now I just have to wait for the package.

[Jsdirt]

Yeah that place is great. Found lots of NLA parts for our '86 Grand Marquis there that I couldn't believe I'd ever find.

[gmtech4]

Found a few videos - looks very easy and quick to replace. Rockauto had the correct one listed for my truck - which has the auxilary rear heat and rear AC. Now I just have to wait for the package.

Replace the connector as well ,, it comes in a pigtail and your old one WILL be melted

 

Always replace bothe resistor and pigtail , stagger the butt connectors for a clean tapped joint

[gmtech4]

Crap - so which pigtail are you referring to? On the videos I've seen it shows two connectors going to the resistor. The pic of the one I bought seems to indicate it comes with a small wiring harness

 

I believe the resistor has a short harness to go to the fan , the other connector that feeds the resistor from the truck is the one , it has many wires and like stated , a solder job is better than the yellow butt connectors that come with the kit

 

Stagger the connection

[calsdad]

Replace the connector as well ,, it comes in a pigtail and your old one WILL be melted

 

Always replace bothe resistor and pigtail , stagger the butt connectors for a clean tapped joint

 

Crap - so which pigtail are you referring to? On the videos I've seen it shows two connectors going to the resistor. The pic of the one I bought seems to indicate it comes with a small wiring harness

 

[calsdad]

Just wanted to follow up about the resistor. After a couple of tries with RockAuto - I finally got the correct part. Their descriptions leave a little to be desired. Put the new part in - checked the wiring and didn't see any issues with it, and now the fan works.

 

There's a whole bunch of other problems with the truck - but at least the fan works now.

[Doug_Scott]

I have little faith in crimp connectors. Soldering and shrink tube is just as easy, and looks far more professional. The resistor blocks failling is so common that they already include the connectors and short harness.

[Jsdirt]

I use heat shrink butt connectors. Had good luck with them in the salty Northeast here over the years. http://www.sherco-auto.com/krimpaseal.htm#krimpa

[Chris]

It does, but you will need some butt splices.