Compass mirror
#1
Burning Brakes
Thread Starter
Compass mirror
I was at the wrecking yard today getting some parts for my daughters car. I found a few cars that had the rear view mirrors with On Star, Home Link and compass. I know I can't wire up On Star to a 1978 Corvette but I was wondering if the Compass was internal in the mirror or is that just a display on the mirror and there is another box somewhere in the car. The ones on the mid 2000 Cadillacs look like they mount with the same windshield button. Anyone know?
#2
Le Mans Master
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It's a simple 4 wire hook-up. Power -ground and two wires to the temp sensor. The compass is in the base of the mount.
Do a search for the Gentex 177. I bought mine off eBay for $30 in excellent condition. Make sure it comes w/ the 7 pin harness. New- sensors are like $25...I have the part# on my home/office computer if you need it.
I put mine on a 71- so I had to to a little modding of the mount to work on the windshield header.
Do a search for the Gentex 177. I bought mine off eBay for $30 in excellent condition. Make sure it comes w/ the 7 pin harness. New- sensors are like $25...I have the part# on my home/office computer if you need it.
I put mine on a 71- so I had to to a little modding of the mount to work on the windshield header.
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1970LS5 (04-23-2016)
#7
Le Mans Master
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I wasn't aware of the smaller Donnelly- The Gentex are 10½"- and the Vettes 74-82 are 10". 69-73 are 8½" The vettes are windshield mount from late 76.
My solution for the smaller years is to use the 74-76 sunvisors.
When I researched the mirrors- Gentex and Magna/Donnelly both are GM suppliers. and have the same harness/ wiring
Here's the wiring for the 7 pin-
GM wire harness color function
PIN 1 PINK POWER +12 volts
PIN 2 BK CHASSIS, GND
PIN 3 LT GRN BACKUP LIGHTS
PIN 4 GY TO AUTO DIM OUTSIDE MIRROR
PIN 5 PINK TO AUTO DIM OUTSIDE MIRROR
PIN 6 DR GRN/WT TEMP PROBE
PIN 7 BK/WT TEMP PROBE
Note: Pin 3 is to be connected to the backup lights to turn off the auto dim feature in reverse. If you intend not to use this feature connect the LT GRN wire to chassis ground. If this pin is floating the auto dim will not work properly.
#9
Burning Brakes
Thread Starter
Thanx for all the responses! I'll hit up the wrecking yard again on Monday see if I can find one without the OnStar buttons.
#11
I put one from a gm pickup in my 74. I removed the factory mirror bracket and glued on the piece for the new mirror on the windshield. Compass is built in the mirror. Easy mod and works great.
#12
Burning Brakes
I really like this upgrade idea. I wonder if you could place the temp sensor somewhere under the hood to monitor engine compartment temps? They may get too high for the sensor to handle.