jimmyjam said:
Can someone say, spoiler alert?
Here's my version of this mod, using a number of relays, diodes, and plenty of wiring.
Disclaimer: I assume anyone attempting this mod has a general understanding of how a relay works, so I'm going to skip over the dirty details involved there.
Starting with the auto-fold logic:
Used a standard 5 pin relay, to connect the timer relays to ground. Used fuse #47 (Ign 0) as the trigger, and a seat bolt as the grounding point.
Ran a pair of wires from there up to the headlight switch area to the pair of Directed Electronics 528T pulse timer relays I grabbed off Ebay. Yellow and Red get connected to constant 12V, black to ground. Brown is the Extend/Retract output signal for the mirrors, and the black & white striped wire is the trigger input from the ignition-ground.
Note: My 528Ts did not work according to the directions, cutting the blue loops didn't cause them to activate properly when the trigger input lost its ground signal. So in the pic, both B&W wires are connected together, but after I took that pic, I separated them and ran them to their own signals from the relay in the rear block after resoldering the blue wires back together
Moving to the OEM switch logic:
Used a DPDT relay hooked up as previously discussed, so when the switch is in the neutral position, Left will extend the mirrors, Right will retract them. When the switch is set to Driver or Passenger, you'll have normal mirror glass activity, and the mirrors themselves will stay put.
Combine the signals through a Polarity Switcher for the mirrors:
Using the same logic from the 194 switchback controller, I used another DPDT relay to accept the inputs from the 528Ts and the switch. Had to put a pair of diodes inline between the switch outputs and the junction with the 528Ts to prevent backfeeding upon startup and shut down. (since the 528Ts use the normally open connection, that aspect is essentially built in) The Retract (+) and Extend (-) are connected to each other, and the Extend (+) and Retract (-) are connected to each other.
As you can see, bullet connectors were my connector of choice, that way I could make it modular and easier for installation and modifications. Of course you know it wouldn't be right if I didn't fit some LEDs in wherever possible. So I Dremeled out part of the turn signal insert, and hacked up a pair of 3157 sockets so they could fit snugly. Already had a parking light wire ran to my doors from a previous LED mirror mod, so just had to connect those up, and now I've got switchbacks in the front, corners and mirrors. Add it all together with some paint and Niteshades, and you get this.
Interesting setup. Mine will be very similar, although the timer relays I have, are activated by grounding them instead of 12V 
ugh: didn't realize that before I bought them), so an additional relay is getting worked into the mix.
If I'm working on a mod that requires the truck to be on, I can just unplug the add-a-fuse during testing, and that should be fine. 
All in all, without the switchbacks, you're probably looking at about $150 depending on where you get your parts, or if you've got stuff laying around already. 
How much is it worth to ya? 
Welcome neighbor! If you click the View & Bid button in the Ebay ad, it should take you to where you need to be if you wanted to buy them. 
. 
). The switch on the Avalanche works left/right.
