Moldy Smell Since Parked

spikesputnik · June 2, 2011

Well I've done the Damp-rid thing for a few weeks and little if any improvement.

I was considering a dilute bleach solution- like 1:20 instead of Lysol.

Any thoughts on this? I guess the whole idea is to kill something growing in the freash air intake...

Eddie 70 · June 2, 2011

I just went out to my truck and sprayed half a can of lysol down the passengers side of the truck intake with the fan on high and fresh air intake. Hopefully this will help. I will finish up the can when I get home this weekend and the truck will set for a week with the lysol in there. I will let you know how it works for my truck.

LeoS41280 · June 2, 2011

There is a bulletin about musty AC smell on the 900's. Go to your dealer and have them turn on the after blow function that is built into our trucks but just turned off.

spikesputnik · June 3, 2011

Leo- what does the after blow function do? Make the truck take a nap?

big_dawg74 · June 4, 2011

Leo- what does the after blow function do? Make the truck take a nap?

That's funny right there!

Jason952 · June 4, 2011

all i had to do in mine was remove the 2 wk old bottle of breast milk the wife left in it....

Eddie 70 · July 2, 2011

Been through the Lysol and whatever the stuff they sell at Advance is called. Still have the moldy smell. This morning I drove for 5 hours home with the windows down and the blower on high, AC off hoping to kill the smell. This evening I went out to the truck and it still smells the same. This is terrible.

Does anyone know if the drain tube can be pulled off the AC box? I think I may give that a shot tomorrow and see if I can get some relief.

Eddie 70 · July 5, 2011

I pulled the drain tube off of mine and ran a 2' long tie wrap through point where the drain tube connects. My box is not stopped up at all. However, the truck has been setting for about 2 days and I did get water to come out of the drain by pushing and pulling the tie wrap in and out of the drain. There was no debris coming out of the drain. Not real sure what my next move is going to be just yet.

LeoS41280 · July 6, 2011

Afterblow Enabling

The afterblow mode can be enabled using the scan tool. The afterblow mode allows the blower motor to operate after the engine has been turned off. This operation of the blower motor dries the evaporator core, which reduces the amount of microbial growth which can create undesirable odors.

Use the following procedure in order to enable the afterblow mode:

•Connect the Scan Tool.

•Turn ON the ignition, with the engine OFF.

•Build the vehicle with the scan tool.

•Select HVAC Control Module

•Select Module Setup.

•Select Afterblow Option.

•Upon selecting the afterblow option a asterix will appear next to the word afterblow meaning the function is enabled.

•Select the save option in the lower left of the screen.

When afterblow has been enabled by the scan tool the blower motor will operate at 68 percent blower speed for 2 minutes 30 seconds to 4 minutes after the engine has been in Key OFF for 30 minutes.

The following conditions must be met for the HVAC module to operate the afterblow:

• The outside air temperature must be at least 21°C (70°F).

• The A/C compressor must have operated during the latest key cycle.

• The engine must be turned off for at least 30 minutes.

• The system voltage must be at least 12 volts.

mdauwald · July 6, 2011

Afterblow will work because I do that manually and have for years. I manually turn the AC off but leave the fan on when I turn into my neighborhood. By the time I get home the AC is blowing cool-warm air and the core is dry so there is no smell the next time I start the vehicle. I never had to do this in AZ or CO but the humid climate here in TX requires it.

Eddie 70 · July 8, 2011

Are you guys running in fresh air mode or recirc mode?

I ask because I run mostly in recirc to keep the conditioned inside air moving across the evaporator coil and prevent the humid outside air off the evaporator coil. Any thoughts on this?

Jeff405 · July 8, 2011

I get the same smell in mine. I keep it parked in the garage most of the week and ride my motorcycle, and normally only drive the truck on the weekends. When I get in, it has a funky smell but goes away pretty quick.

jdewolfe · August 15, 2011

Can this after blow feature be enabled on an 06 Sierra?

LeoS41280 · July 26, 2015

Leo- what does the after blow function do? Make the truck take a nap?

It will help cure the musty odor you are talking about. If you have RPO codes CJ2,CJ3,or CJ7 there is an afterblow function that can be turned on to prevent evaporator core odor.

jhm · July 27, 2015

Are you guys running in fresh air mode or recirc mode?

I ask because I run mostly in recirc to keep the conditioned inside air moving across the evaporator coil and prevent the humid outside air off the evaporator coil. Any thoughts on this?

I always run on recirc. you could have mice. set some traps under the hood and on floor see if you catch any. I once had them get behind the firewall, chewed the silver cover and got in the insulation, and I was driving it every day.