2000 silverado and ultrastart 1272

First, make sure the GWR wire is disconnected if you want to stay with D2D.  Personally, with the U1272, being as it has a nice plug with bypass power, ground and GWR all ready to go, I just use that harness & use  W2W mode. 

While the U1272 install manual indicates that it will auto-program to Fortin if D2D is connected when prower is first applied, I think I would still go into programming and manually change it to "Fortin bypass" to be sure.

The INT-SL+ resets itself during Steps 2 & 3 of the programming ( applying power with the button depressed ).

Going with Tach Mode operation is always the best way to remote start a vehicle.  It is worth the extra effort to make the Tach wire connection.  Just remember to warm up the engine, do a Factory reset on the U1272, and then just start the engine.  Watch for the correct Parking Light flash ( and horn beep ).  After the reset, you must go back into programming and make your changes all over ( except Selectable ignition relay ).

Soldering is fun!

Got it. I did change the program to "Fortin Bypass" when I installed it. I will connect the tach wire for him tonight, and reprogram. I'll keep ya posted.

Ok, well, followed everyones advice, I got nothing. I connected the Tach wire, and followed the setup for the 1272 to sense the Tach. That worked no problem. I moved on to programming the Fortin. This is where the problem lies. I hold the button, plug in the black harness. LED comes on. I release the button, and plug in the other harness ( it is NOT upside down). LED stays on. I hit the Lock button on the 1272 remote, doors lock, Fortin LED still on. Turn truck to ignition position. Wait, and wait, and wait... for the LED to flash. it never does. Where am I wrong?

That's the thing, I can't get past step 7. When I press the lock button, the led stays on. I turn the key to ignition, and wait. The led never blinks, so I can never move on to starting the truck. For the sake of argument, I did try rs the truck. It cranks, but won't turn over. So I know its not getting past the Passlock, which means the Fortin is not programming. During the step where I press the RS lock button so the Fortin sees a signal, how do I know it gets a signal. What I'm saying is, once I press the program button in step 1 and plug in the harness, the led does come on, showing power. But no matter what step I move to, it always stays on.

Doesn't look like the LED has to turn off at Step 5.  The LED is supposed to Flash at Step 7.  Perhaps you should use a DMM and verify that the INT-SL+ Pink wire is connected to the trucks Pink Ignition 1 wire and getting +12V when the key rotates to the ON position.  If nothing happens after 2 minutes just continue to Steps 8 - 10 and then see what happens.Soldering is fun!

Well, I'm completely lost. I can't get this thing going. Here is what I have connected- 1272-------------Truck-----------------------------Fortin red 12v red(ign harness) Blue(ign) pink(ign harness)   pink white(sel output) white(ign harness) green(heater output) orange(ign harness) yellow(start)       yellow(ign harness) park lights- brown brake-white(brake switch) horn- black(ign harn) tach- behind guage cluster           purple at OBD portpurple WHITE/ purp  blue D2D connected-but white and blue cut-just red and black connected So, these are the connections I have made and double checked. Do I need to connect the arm-disarm wires on the RS? Truck does NOT have factory alarm. I have manual tach programmed, and 1272 indicates it senses it with confirmation honks. I still have not been able to successfully program Fortin. On step 5, it states to press lock on the 1272 remote so it sees a signal. I get no confirmation that it does. When I move to step 6, I turn the key to ign, and wait for LED flash. I never get one, even after 5 minutes. I move on to step 8, just to see. When I remote start truck, truck cranks, sounds like it wants to turn over, and immediately dies. It tries this 3 times in a row, and gives the feedback of 8 light flashes. Please help, I feel bad, as this is my buddies wife truck, and we are getting 4-6 inches of snow right now!

Just for grins, at Step 5 try briefly  connecting ( 1 sec ) the INT-SL+ Light Blue wire to chassis ground.  See if that allows you to continue with programming and getting the correct responses.Soldering is fun!

I will do that

Unfortunately, nothing happened. Still cranking, no turn over. One other issue that popped up, the truck has tried magically starting on it's own twice now, (according to my friend), and when unlocking the truck with the 1272 remote, the horn goes off like it's in panic mode, and won't shut off until truck is started. I need to get more info from his wife about this, but they swear the remotes were not accidently touched. So very frustrating....