Gentex GNTX-221 Mirror Wiring

Mangelhaft

New Member
Joined
Oct 6, 2018
Messages
3
Location
Dearborn, Mi
I posted this as a reply in another thread. I scoured the internet for the information on the GNTX-221 dual display version. I was unable to find anything accurate. I disassembled all four of the GNTX-221 variants and did some detective work tracing PCB paths. I then reassembled the mirrors and electrically tested my data. This is the result.

I have identified four different versions of the GNTX-221 mirror:
Map Lights Only
Map Lights & Compass
Map Lights, Compass, & Temperature - Single line display
Map Lights, Compass, & Temperature - Dual line display

The first three have almost the same connector pin-outs. The ones without the temperature display appear to have the feeds for side mirror dimmers. The ones with temperature display have inputs for the temperature sensor in place of the side mirror dimmer feeds.

The dual display is different.

Here are the pin outs:

I I
I 1 I 2 I 3 I 4 I 5 I 6 I 7 I
I_____________________I

GNTX-221 - Map Lights Only
1 - +12V Switched-RUN/START
2 - Ground
3 - Reverse Feed (+)
4 - Door Mirror Feed (+)
5 - Door Mirror Feed (-)
6 - Door Switch (-)
7 - Fused B(+)

GNTX-221 - Map Lights & Compass
1 - +12V Switched-RUN/START
2 - Ground
3 - Reverse Feed (+)
4 - Door Mirror Feed (+)
5 - Door Mirror Feed (-)
6 - Door Switch (-)
7 - Fused B(+)

GNTX-221 - Map Lights, Compass, & Temperature - Single line display
1 - +12V Switched-RUN/START
2 - Ground
3 - Reverse Feed (+)
4 - Temp Sensor (+)
5 - Temp Sensor (-)
6 - Door Switch (-)
7 - Fused B(+)

GNTX-221 - Map Lights, Compass, & Temperature - Dual line display
1 - FUSED B(+)
2 - Door Switch (-)
3 - Temp Sensor (-)
4 - Temp Sensor (+)
5 - Reverse Feed
6 - GROUND
7 - +12V Switched-RUN/START

IF anyone finds any errors, please let me know.
 
How thoughtful of you to put this together. This will be tremendously helpful for people in the future, I'm sure of it.

I installed the Gentex 221 mirror on mine, but I got the factory wiring harness that plugs in on top of the dash, so it was plug-and-play.

The funny thing is, there's actually several different versions of the Gentex 221 mirror. The only one that will plug-and-play with the factory wiring is the one where it has a double DIN display where the temp and compass display at the same time. There's also a single DIN version as well which I have in my closet where only one piece of info will display at a time. Both the exact same part numbers, which I found very odd!
 
Thanks so much for your efforts!!!! Does any one know in a U-pull it yard, what vehicle has a 221 double din installed and to build a wiring harness between the top of the dash and the mirror, what all is needed? Thanks