Fan Blower Only Works On High - 1999 Suburban

[TurboDiverArt]

Hi All,

My blower only works on high. Normally I would simply say it's the switch but as with many things on these trucks things can sometimes not be as simple as they seem. I tried checking voltage at the back of the switch but honestly couldn't make any rhyme or reason of it. Maybe if I knew the wiring pin out it might make sense. I would change the switch position and would seem to see voltages on different wires at different times. I definitely saw more than 2 voltages with any one position so it confused me.

Is there any thing other than the switch that it could be?

If it's the switch, can I replace just the switch or do I need to buy a complete control panel? My Suburban has a rear A/C/heater unit in the back if it matters. My truck was manufactured in 1998 so may have the same controls as a 1998. mine does not have temperature numbers but just the blue/red colors on the temp control.

Any help would be appreciated!

[Dvldog8793]

Howdy
It could be two different items. The switch or the resistor pack that is located in the blower box. Both of these things are prone to failure.

The resistors are cheap, kinda tricky to replace, but that's what I would start with.

The climate control is EXPENSIVE. They fail often enough that my neighbor with the salvage yard buys them aftermarket new to have on the shelf. If I remember correctly, the lower settings are routed directly through the switch and the high setting is routed separately. Check all the connections at the switch for melting.

Another item to check while your in there...the connection to the blower fan is prone to melting as well.

Hope this helps!

[TurboDiverArt]

Sorry for taking a while to reply. The resistors in the blower box. I think I remember changing the blower motor a while ago. I think you just remove the glovebox for better access and it just unbolts and slides out? The resistors are in there? Are they individual resistors or are they in an assembly like they use to be on older cars? Looking like spiral coils? I assume you just check the resistance across them? If they Ohm out not to have any continuity across them they are bad? If they don't show any voltage into them then it's the switch?

Thanks again for the info!

[Dvldog8793]

The resistor pack is just as you said, coiled wire resistors. The only tricky part, IIRC, is one of the screws requires very small double jointed fingers....or maybe it was just me:rolleyes:. The resistor pack was pretty cheap....$20.00...so when I started having problems I just replaced it. Between the four trucks of that vintage that I own/owned I have replaced the resistors in them all and the climate control in two of them. The wire connector down by the blower motor was melted in all of them and the connectors on the climate control showed heat damage on all of them as well.
Have fun!

[TurboDiverArt]

Thanks so much, that makes a lot of sense. I was able to buy a new switch from Rock Auto, it was cheap, like $15. I couldn't find the resistor pack or I would have ordered one of them too. I'm going to try and work on it this weekend, among all the other things I need to work on.....

Thanks again!

[a5150nut]

Something like this http://www.youtube.com/watch?v=qxWM285eizw
I had to do almost the same on my wife’s Liberty. I think he even gave teh Delco part number at the beginning of the video.

[Dvldog8793]

Howdy
The video is for a newer type chevy Silverado. It appears to be much easier! The wire connection that I was referring to is actually on the motor power wire.
Hope this helps!

[TurboDiverArt]

Replaced the resistor module and my fan is working correctly. It's a tight fit to get your hands up on top of the air duct to get to the module but at least you can fit a small 1/4" ratchet to the screws to remove it. Note to others, remove the electrical connection first before removing the 2 screws that hold the resistor module in place. If you remove the screws it's difficult to get the connector off. If it's still screwed in place you can pretty easily pop the connector off using a screwdriver to pry it off.

Thanks for all the help!

[a5150nut]

Thank you fro the update. Glad to hear it is working again.