1999 Suburban Electrical / Fan Blower Automatically Comes on.

[matthewr]

Help!!! I am running into a problem with my fan blower automatically coming on. When the 99 Suburban is sitting in my garage, the fan blower for the airconditioner comes on, along with the 4x4 lights on the buttons, also, the air starts blowing out the vents. Even if you turn the A/C to the off position, the blower will turn on; however, nothing will come out of the vents. This is not the fan in the front of the engine. This is the A/C blower. It has done this for almost 2 years. It just gets really annoying. Please also note that the engine is cold, warm, hot... It does it all the time. It will come on about every 15 minutes. Please let me know if you can help.

[jeff_heintz]

Originally Posted by matthewr

Help!!! I am running into a problem with my fan blower automatically coming on. When the 99 Suburban is sitting in my garage, the fan blower for the airconditioner comes on, along with the 4x4 lights on the buttons, also, the air starts blowing out the vents. Even if you turn the A/C to the off position, the blower will turn on; however, nothing will come out of the vents. This is not the fan in the front of the engine. This is the A/C blower. It has done this for almost 2 years. It just gets really annoying. Please also note that the engine is cold, warm, hot... It does it all the time. It will come on about every 15 minutes. Please let me know if you can help.

I would start by looking at your blower relays. Is it the the front blower or the rear blower (near the rear doors)? If it is the rear blower there are 3 relays (not shown in the manual) located under the plastic shelf on the rear passenger side forward and above the blower motor. I had one in my '97 K1500 that would short sometimes when the vehicle was off and run the blower until it drained the battery.

[mrrpm]

I have a '99 that does the same thing. Blower will come on, run about 5 seconds, then shut off. Mine only does this when it is not running - key not in the ignition. I was thinking it was possessed. Guess I'm not the only one! Unfortunatly, I haven't looked into what's causing it yet. If I find out, I'll be back with a post!

[matthewr]

Originally Posted by mrrpm

I have a '99 that does the same thing. Blower will come on, run about 5 seconds, then shut off. Mine only does this when it is not running - key not in the ignition. I was thinking it was possessed. Guess I'm not the only one! Unfortunatly, I haven't looked into what's causing it yet. If I find out, I'll be back with a post!

Doesn't it suck... I thought I was the only one with this problem. I am going to take the other individuals response and try replacing the relays. I will let you know if this works.

[matthewr]

Originally Posted by jeff_heintz

I would start by looking at your blower relays. Is it the the front blower or the rear blower (near the rear doors)? If it is the rear blower there are 3 relays (not shown in the manual) located under the plastic shelf on the rear passenger side forward and above the blower motor. I had one in my '97 K1500 that would short sometimes when the vehicle was off and run the blower until it drained the battery.

It is the front blower. Since it is the front blower, would the Relay be in the Fuse Compartment? What would it look like? I don't want to pull something out that might not go back in... Any advise would be great.

[TJ_in_IL]

The blower coming on is a mod that was made by the dealer based on a TSB (99-01-39-004A), referring to musty smell from the AC.
This is actually an Electronic Evaporative Blower Motor, which will activate for 10 seconds every 30 minutes up to 2 hours after shutdown. This prevents moisture buildup on the condensor coils, preventing mold and mildew buildup. It has a built in low batter detection,l which will halt operation if the battery dropt below 12.5 volts.
Run a google search on "Electronic Evaporative Dryer" , or bthe TSB for more information.
Also, under the hood should have a sticker indicating the mod was made. (Mine does, and I ran the search to see what it was).
Hope this helps!