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2004 Envoy xl rear blower runs with car off

2004 Envoy xl Rear blower motor continues to run when turned off, runs full blast running or with ignition off, front switch has no effect, rear switch has no effect. pulled rear fuse, please advise on fix. poss rear blower resistor?

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2004 envoy xl When ever I turn on the rear ac it comes in short bursts and most of the time does not even work.

Sounds like it could be a relay failing. Find the relay for the rear blower fan and switch it with a like relay.

May 22, 2014 | 2004 GMC Envoy

1 Answer

GMC 2004 Envoy blows heat even with blower off ... Why ?

The relay in your blower motor is stuck on, there is a TSB for this issue. Replace the blower motor resistor and you'll be back in business.
How does the resistor get power if the fuse is pulled?
Replacing the resistor will cure both problems. TSB is a technical service bullitin seen below
Subject:HVAC Blower Motor May Run Continuously After Vehicle is Turned Off (Replace Blower Resistor Relay)Models:2004 Chevrolet Avalanche, Silverado, Suburban, Tahoe, TrailBlazer, TrailBlazer EXT2004 GMC Envoy, Envoy XL, Sierra, Yukon, Yukon XLwith Manual Control HVAC (RPO CJ3)Built Prior to August, 2003

Jun 04, 2013 | Cars & Trucks

1 Answer

The fan is stuck blowing on high, the knob turns etc... but the fan and condenser run full blast

Check the connection at the heater blower motor resistor.Wiggle or pull connector off and look for a melted pigtail these get very hot and usally are the cause of fan motor problems.Its located on passenger side of heat duct mounted with 2 screws.

Feb 17, 2012 | 2003 Chrysler Town & Country

1 Answer

Heat and aircondition.My heat and air only work on number 5

Sounds like a "fan motor speed controller" or FMSC.
Either that module has gone out...or we're not getting the signal from the control panel sometimes called the EATC.

Lincoln has an EATC (for electronic air temp control)...GMC has something similar.
There is a way to run a diagnostic test of the EATC but am having trouble finding it for GM models.

If EATC test is done and will tell you it failed and would need replacing.
If EATC will tell you it passed and the fan motor speed controller would be at fault.

Usually, when a speed controller fails, the blower motor either doesn't turn OR it runs full blast.
Both parts EATC and the FMSC are expensive.
Since yours is running full least its providing air.
I'd try to run a diagnostic check to be for sure and maybe your parts might be less expensive and available at your local parts store.

Hope this helps...

Aug 13, 2011 | 2004 GMC Envoy

2 Answers

Blower motor continues to run when vehicle is off

Your problem is the Relay which is encased inside the Heater/AC Resistor Module. This is a very common problem with GMC and Chevy Trucks. The Relay's return spring fails and the relay is held closed by gravity. The only fix is to replace the Resistor Module. I have a 2004 Silverado and have replaced the Module 3 times and the Blower Motor twice. The Orange wire feeding the Module is always Hot (12V) and feeds the Relay Contact for Highest Blower Speed. Hence the Blower runs all the time even with the Key off and removed.

Oct 02, 2009 | 2003 GMC Envoy Xl

1 Answer

Rear a/c remaining on when engine is off

999999995.gif Service VME - HVAC Blower Continues To Run with Key Off SERVICE VME Some 2003 Full-Size Pickup / Utility A/C blower motor continues to run even when the key is removed from the ignition. The root cause is an internal failure within Linear Power Module ( LPM ) or also known as the Blower Motor Control Processor. The service fix is to replace the LPM (P/N 52495874).


Aug 25, 2009 | 2003 GMC Yukon

1 Answer

A/C blower motor keeps running when ignition turned off

I had the same thing on my 2004 Envoy and it was the blower motor resistor. Dealership wanted $240 to replace and I did it in 20 minutes for about $50. Bought the part at NAPA. I found out by searching on Google how to replace it. Hope this helps.

May 25, 2009 | 2003 GMC Envoy

1 Answer

Rear heat blows cold air

one of the second heater core lines is clogged.

Jan 05, 2009 | 2004 GMC Envoy

1 Answer

2004 denali rear hvac

I had this same problem, With it running and heat and blower on full blast remove and unplug the rear faceplate for the rear heat.
Unplug for about a min.
Shut off engine.
Cycle the key 5 times.
Start engine.
Plug in the plug to the face plate.
For about a min. nothing will happen no heater no blower.
After the multiplex system refinds its address, the rear heat will then work again.
this worked for my 04 trailblazer.

Dec 21, 2008 | 2004 GMC Sierra Denali

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