- Joined
- Aug 19, 2010
- Posts
- 28,638
- Reaction score
- 10,050
- Location
- Kansas City, Mo
- First Name
- Jacob
- Truck Year
- 1977/1990/1991
- Truck Model
- C10 longbed/R1500 Burb/R3500 Dually
- Engine Size
- 350/350/454
**Let me start this by saying I used Retro's write up from a different site do complete this mod so ALL of the credit should go to him. With his permission, I've taken his write up and copy/pasted it here for GMSB to enjoy. I could not have posted it any better than he did so I chose not to try 
Obviously, there are some small differences as his write up is actually for an S-Series but it was good enough for me to be able to adapt it to my '77 **
Installing an electrochromic (auto-dimming) rear view mirror in your S-Series (this also works for 73-87).
Difficulty: 2/10 (10 hardest)
This is a how to on installing an auto-dimming rear view mirror (with or without compass,
without map lights) in your first gen S10. Second gen is likely the same for the most part.
Install at your own risk as this involves a little wiring work.
Don't you hate driving at night and when someone comes up behind you with bright lights
and you have to flip the little lever on the mirror? I do too, so I have installed
these mirrors in most every car I have owned. Even with tinted windows, those bright lights
can be a pain in the eye.
What you will need:
1. mirror - most higher end GMs have this mirror, they can be had with compass, with temp, with maplights. I got mine from a 1995 Olds 88 LSS. Don't forget the connector with a little wiring! This write up involves compass and auto-dim. One day I will do a write up with map lights and temp.
2: length of wire. 18 gauge will be fine.
3. phillips screwdriver.
4. largish flat blade screwdriver
5. T20 Torx
6. wire cutters/strippers
7. 7 mm (9/32) socket and ratchet or nut driver
8. spade connector
9. soldering iron and solder
10. Shrinkwrap or electrical tape
11. beer (optional)
12. 45-60 minutes
Getting your new mirror. Look for a Buick, Cadillac, Chevrolet, GMC truck or Olds with the mirror you want.Get a GENTEX model because the Donnelly's tend to leak the fluid. They are held on by a small clip that slides over the button on the windshield. Take the flat blade screwdriver and go up under the base and GENTLY pry between the glass and the mirror base while wiggling the mirror towards the top of the car. SOme are held in by a T20 Torx screw, these are better. Most junkyards charge $5-35 for these. Depends on where you go. Or you can find them on ebay.
Take off the old mirror in your truck. Most are just your standard day/night.
But many first gens had map lights. There is a set screw holding it to the button. Generally it's a phillips or a T20 TORX. Remove the mirror.
If you had the map lights, there's a connector you need to unhook.
Take your phillips screwdriver and remove the three screws holding the driver's sunvisor. Unplug the connector to that if you have the vanity mirror and set aside.
Now, take the two screws holding the A PILLAR trim and gently pull it off and set it aside. Also go ahead and pull off the under dash cover to get to the steering column and fuse box.
Now you're ready to install the new mirror. Oftentimes, when you pull one of these mirrors the clip that holds it on to the windshield button gets all fubar'd and the mirror will be loose. I'll either use the base from the old mirror OR take the compass off and drill a hole in the base for a set screw from the old mirror. The latter is the easiest and once you reinstall the compass, it disappears.
But, first thing is first. You need to run some wiring. You can't use the original harness for the map lights except the ground. The ground on your new mirror will be NO. 2 on the connector. No. 1 - far left in pic, yellow in color, some are different colors - is ignition and will go to the fuse box. No. 3 will be for the reverse light switch - this is optional and will be covered in a few. So, tie into the black wire on the original connector or if you don't have this, run a wire to the a-pillar and drill a hole in the metal and run a screw in to tie down the wire and ground it. Never mind the other wires, these are for DIMMING SIDE VIEW mirrors...Another project for another how to coming later.
Now tuck the map light connector up in to the headliner as it won't be needed and possibly return the truck to stock if you desire some day. Of course, remember to wrap your splice in shrinkwrap or electrical tape. Now run a wire from No. 1 in the connector, tuck it in to the headliner and run it down to the map light or dome light wiring and take it to the fuse box. There's an empty space marked IGN and cut the wire to length, add the spade connector, solder, shrinkwrap, tape and plug it in to the IGN.
(OPTIONAL) Now, run the wire from the No. 3 (green) on the mirror connector with the ignition wire down to the STEERING COLUMN, find the wire on your neutral switch for the BACK UP LAMPS, on my truck, it is LIGHT GREEN. Splice in to this. What this does is disables the auto-dimming when the truck is in reverse. Useless to me though. Leave it unhooked if you desire.
Install your mirror on the windshield and tuck the wiring harness up in the headliner and route it using the cover if you got one with the mirror. Taking care not to damage the harness, reinstall your sunvisor, a-pillar trim and underdash trim.
If you have the COMPASS, you will need to calibrate it. To do this, look up at the bottom of the mirror and find the calibration button, to push it in, you will need a straightened paper clip. Press the button until the display says "C", then drive in a complete circle until a direction is shown in the display.
Now, with the ignition on press the button for 3-4 seconds and it will generally say "8", this is the zone for the compass. press the button until the number 6 is shown. This is the zone for TEXAS.
You're ready to enjoy safer night driving! Also, if you have the compass, it is easier for you to find your way.
This post originated at http://www.catfishgoons.com/index.php?showtopic=455
Obviously, there are some small differences as his write up is actually for an S-Series but it was good enough for me to be able to adapt it to my '77 **Installing an electrochromic (auto-dimming) rear view mirror in your S-Series (this also works for 73-87).
Difficulty: 2/10 (10 hardest)
This is a how to on installing an auto-dimming rear view mirror (with or without compass,
without map lights) in your first gen S10. Second gen is likely the same for the most part.
Install at your own risk as this involves a little wiring work.
Don't you hate driving at night and when someone comes up behind you with bright lights
and you have to flip the little lever on the mirror? I do too, so I have installed
these mirrors in most every car I have owned. Even with tinted windows, those bright lights
can be a pain in the eye.
What you will need:
1. mirror - most higher end GMs have this mirror, they can be had with compass, with temp, with maplights. I got mine from a 1995 Olds 88 LSS. Don't forget the connector with a little wiring! This write up involves compass and auto-dim. One day I will do a write up with map lights and temp.
2: length of wire. 18 gauge will be fine.
3. phillips screwdriver.
4. largish flat blade screwdriver
5. T20 Torx
6. wire cutters/strippers
7. 7 mm (9/32) socket and ratchet or nut driver
8. spade connector
9. soldering iron and solder
10. Shrinkwrap or electrical tape
11. beer (optional)
12. 45-60 minutes
Getting your new mirror. Look for a Buick, Cadillac, Chevrolet, GMC truck or Olds with the mirror you want.Get a GENTEX model because the Donnelly's tend to leak the fluid. They are held on by a small clip that slides over the button on the windshield. Take the flat blade screwdriver and go up under the base and GENTLY pry between the glass and the mirror base while wiggling the mirror towards the top of the car. SOme are held in by a T20 Torx screw, these are better. Most junkyards charge $5-35 for these. Depends on where you go. Or you can find them on ebay.
You must be registered for see images attach
Take off the old mirror in your truck. Most are just your standard day/night.
But many first gens had map lights. There is a set screw holding it to the button. Generally it's a phillips or a T20 TORX. Remove the mirror.
You must be registered for see images attach
If you had the map lights, there's a connector you need to unhook.
You must be registered for see images attach
Take your phillips screwdriver and remove the three screws holding the driver's sunvisor. Unplug the connector to that if you have the vanity mirror and set aside.
You must be registered for see images attach
Now, take the two screws holding the A PILLAR trim and gently pull it off and set it aside. Also go ahead and pull off the under dash cover to get to the steering column and fuse box.
You must be registered for see images attach
You must be registered for see images attach
You must be registered for see images attach
Now you're ready to install the new mirror. Oftentimes, when you pull one of these mirrors the clip that holds it on to the windshield button gets all fubar'd and the mirror will be loose. I'll either use the base from the old mirror OR take the compass off and drill a hole in the base for a set screw from the old mirror. The latter is the easiest and once you reinstall the compass, it disappears.
You must be registered for see images attach
But, first thing is first. You need to run some wiring. You can't use the original harness for the map lights except the ground. The ground on your new mirror will be NO. 2 on the connector. No. 1 - far left in pic, yellow in color, some are different colors - is ignition and will go to the fuse box. No. 3 will be for the reverse light switch - this is optional and will be covered in a few. So, tie into the black wire on the original connector or if you don't have this, run a wire to the a-pillar and drill a hole in the metal and run a screw in to tie down the wire and ground it. Never mind the other wires, these are for DIMMING SIDE VIEW mirrors...Another project for another how to coming later.
You must be registered for see images attach
Now tuck the map light connector up in to the headliner as it won't be needed and possibly return the truck to stock if you desire some day. Of course, remember to wrap your splice in shrinkwrap or electrical tape. Now run a wire from No. 1 in the connector, tuck it in to the headliner and run it down to the map light or dome light wiring and take it to the fuse box. There's an empty space marked IGN and cut the wire to length, add the spade connector, solder, shrinkwrap, tape and plug it in to the IGN.
You must be registered for see images attach
(OPTIONAL) Now, run the wire from the No. 3 (green) on the mirror connector with the ignition wire down to the STEERING COLUMN, find the wire on your neutral switch for the BACK UP LAMPS, on my truck, it is LIGHT GREEN. Splice in to this. What this does is disables the auto-dimming when the truck is in reverse. Useless to me though. Leave it unhooked if you desire.
Install your mirror on the windshield and tuck the wiring harness up in the headliner and route it using the cover if you got one with the mirror. Taking care not to damage the harness, reinstall your sunvisor, a-pillar trim and underdash trim.
If you have the COMPASS, you will need to calibrate it. To do this, look up at the bottom of the mirror and find the calibration button, to push it in, you will need a straightened paper clip. Press the button until the display says "C", then drive in a complete circle until a direction is shown in the display.
Now, with the ignition on press the button for 3-4 seconds and it will generally say "8", this is the zone for the compass. press the button until the number 6 is shown. This is the zone for TEXAS.
You must be registered for see images attach
You must be registered for see images attach
You're ready to enjoy safer night driving! Also, if you have the compass, it is easier for you to find your way.
You must be registered for see images attach
This post originated at http://www.catfishgoons.com/index.php?showtopic=455
Last edited:
) and those wire into the harness at the mirror and you just run your wire. That's the easiest part of the install 
