I have a 2006 Envoy SLT. I need to replace the power side view mirrors. My current mirrors do not have heat. I was thinking of getting mirrors with heat. I believe they are operated off the rear window defroster switch. Can anyone tell me if the are just plug and play. The cost difference is not large and will keep wife happy, but do not want to go into any big modifications. Thanks in advance
NEED HELP change from nonheated to heater side view mirrors on 2006 envoy SLT
- Thread starter bogart1
- Start date
This is a pretty good "How To" and Bench Top Product Testing prior to the Install. The supplied Simple Switch would need a proper In-line Fuse for both sides and perhaps some way to ensure that when the Ignition is OFF... that the Two Mirrors also Turn Off... regardless of whether the supplied On/Off Switch is in either state:
Let's Toss in THIS Video about "How to Properly Wire In (SOLDER!) the Runs to the Insulated Connectors fitted at the RELAYS" to cover the additional safety needed when doing Add-Ons or Wired-In Appliances that can draw enough HEAT to Quickly Short Out the Fuse ...or Damage the Small Dash Switch by allowing WAY TOO MUCH CURRENT to pass through:
Let's Toss in THIS Video about "How to Properly Wire In (SOLDER!) the Runs to the Insulated Connectors fitted at the RELAYS" to cover the additional safety needed when doing Add-Ons or Wired-In Appliances that can draw enough HEAT to Quickly Short Out the Fuse ...or Damage the Small Dash Switch by allowing WAY TOO MUCH CURRENT to pass through:
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Blckshdw
Moderator
If this "Get-Up IS Set-Up" with the Mirrors Heater Switch running through the Ignition Switch Harness as the intermediary, then the BCM would not need to be involved at all. The important thing is that when the Driver looks at the Iced Up Mirrors, his attention will be drawn to check for the "Red Dot" on the Mirror Switch. But should he forget to TURN IT OFF... It won't make any difference whether it is ON or OFF when the Ignition Key is removed ... and thus... NO DEAD BATTERY.
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I will further add what I have found in my data repository thus far.
I have a 2002 TrailBlazer and a 2005 Yukon. The Yukon has heated mirrors and the TrailBlazer does not.
In the Yukon the HVAC module sends the instruction to turn the heaters on or off in a message to the mirrors subsystem, functional address pair C2 & C3. Each door module responds to the message reporting each has performed the instructed action. The messages are highlighted here. The third byte is the senders address, 98 is the HVAC module, A1 is passenger door, A0 is drivers door.
I did not find the same for my TrailBlazer but this could be because I just haven't caught the whole operation yet in my data repository which currently consists of over a thousand recordings. That plus this TrailBlazer did not come with that option. I DID however find messages from the HVAC module instructing the mirror subsystem to turn off the heaters but NO instructions to turn them ON, and NO door modules respond to these messages. I intend to do a deliberate test for these actions today and will update here.
I have a 2002 TrailBlazer and a 2005 Yukon. The Yukon has heated mirrors and the TrailBlazer does not.
In the Yukon the HVAC module sends the instruction to turn the heaters on or off in a message to the mirrors subsystem, functional address pair C2 & C3. Each door module responds to the message reporting each has performed the instructed action. The messages are highlighted here. The third byte is the senders address, 98 is the HVAC module, A1 is passenger door, A0 is drivers door.
I did not find the same for my TrailBlazer but this could be because I just haven't caught the whole operation yet in my data repository which currently consists of over a thousand recordings. That plus this TrailBlazer did not come with that option. I DID however find messages from the HVAC module instructing the mirror subsystem to turn off the heaters but NO instructions to turn them ON, and NO door modules respond to these messages. I intend to do a deliberate test for these actions today and will update here.
Correction!! Turns out my truck DID have this option, RPO DK2.
I also failed to note that both of my vehicles have the CJ2 automatic (digital) HVAC controls. Maybe doesn't matter??
And I can now add that in fact the message structure in the TrailBlazer is nearly identical to that of the Yukon, just a small difference in message priority. Otherwise the same, the HVAC module commands the mirror heat on or off and the door modules perform the action. The rear defrost button is the trigger, the front defrost does not trigger the mirror heat.
So this does not really prove that all TrailBlazers have the programming I guess since I don't have access to a truck that lacked the DK2 RPO from the factory so I cannot test for that.
Blckshdw
Moderator
Allow me to assist for a change 
I have a plane Jane LS model, that had the basic mirrors. I added power folding mirrors some time ago, and they have the heated option. I crammed a my meter leads in there and tested it. Sure enough, I get voltage when the rear defrost button is pushed.
I have a plane Jane LS model, that had the basic mirrors. I added power folding mirrors some time ago, and they have the heated option. I crammed a my meter leads in there and tested it. Sure enough, I get voltage when the rear defrost button is pushed.
Mooseman
Moderator
Also, if you want to upgrade even further, get a set with turn signals. Plugs right into the DDM and PDM along with the heaters.