4103 Remote Starter, 2003 GMC Sierra

Back in the 90's and early 2000's I've installed thousands of remote starters.
I am trying to install a 4103 in my friends 2003 Sierra and it's giving me a headache! Won't start, just cranks. SO my first idea was his passlock was the issue. Well after a ton of trouble shooting I determined it is his tach wire. I get signal all the way down to the plug. a nice 800 rpm signal, but when I plug the white plug into the brain the signal goes straight to ground. I unplug it and its back. So I'm THINKING its an internal issue with the 4103 itself, but wanted a second opinion as well. ALSO ;). I can't get the lock/unlock working. I know its the Lt Blue and White wire at the PCM. I have a 2005 Sierra and its identical. But when I hook up the blue and green wire to them they don't do anything at all.

Thanks for ANY help that can come outa this :)

A lot of issues. If you have a relay, wire it up with +12V to Pin 86
and connect the 4103's lock or unlock output wire to Pin 85. See if a
lock or unlock command energizes the relay for a second. That will
check the 4103's lock outputs.

If you are connecting the 4103's Violet/White Tach wire to the trucks
White Tach wire at the instrument cluster connector and the signal
drops to ground when the H2 5 Pin Remote Start harness is plugged into
the brain, that's a problem. You need that connector for the Neutral
Safety, hood pin and the foot Brake signal. You could omit the Tach
for now and run in Virtual Tach to test everything else.

What did you use for the Passlock2 bypass? Without a bypass, the
engine will crank but no gas will get to the injectors.

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Soldering is fun!

Yeah I can hook relays to the door locks. Odd that I never had to with my truck.
For the over ride module we first tried the GMDLBP but out of the box I can't get it to program to Type 4, press the program button and absolutely nothing happens, so I switched to an old PKALL that I had and used that under Type 2 and programmed that.
I use my bitwriter and tried virtual tach, voltage and off and the truck still just does one quick crank and shuts down. Diagnostics has the 3 blinks which is Low or No RPM.
The Passlock light on the dash doesn't flash, in fact after installing the system the light stays on all the time, but the truck starts just fine with the key itself.

The relay was just to test the 4103's outputs. Remember that only the base
models can use (-) door lock signals. All other models need a door lock module
to handle the multiplex lock signal. See note below from Omega :
** The wires listed are for Base Models only. DUE TO MULTIPLEXING in all other
models, you must use an interface module to do door locks.

Something sounds off on the bypass module. Having the Passlock light on all
the time isn't good. As far as I remember, the PKALL is only for transponder
key/chip systems, not Passlock2 resistance systems. If the GMDLBP isn't
working, try getting a Fortin INT-SL+ which will do everything including
supply a Tach signal. You will have to go W2W to the 4103.
Here is a link to the INT_SL+ install guide :

https://cdn02.fortin.ca/download/46281/int-sl+_revj.pdf


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Soldering is fun!