viper 5901 alarm trigger during rs

first of all how many triggers do you have on the blue trigger input on the brain?

my guess would be that the battery voltage is dropping so much while the starter cranks that the 520t that it is triggering the alarm.

unhook the 520t from blue wire and see if the problem goes away. if it does, install a relay to keep that wire disconnected while remote start is being used.

keep us posted.

place a diode inline with the trunk wire, see if its getting any backfeed to trigger the system from the factory alarm unit.

cut the trunk trigger wire, connect it to switch side and see if it faults when you start. if it doesnt then you are getting some feedback, a diode should fix this.

OK, update.

First on the battery issue, No drop in voltage with the battery.  It is also a brand new deep cycle Optima Yellow top.  The backup battery is also at full charge.  When cranking the car, the voltage barely drops.

Second, here is my current setup on the trigger wire.

BEFORE:  I installed (2) N007 diodes, band out from brain, on the trigger wire, one to the ADS trunk output and the other to the blue wire from the 520T.  AFTER doing this, the car would auto start BUT I was getting a chrip and a trunk notification on the remote.  Before the diodes, it would just trigger the alarm.  I then popped out the connector for the blue wire on the 520T (removed it from harness, it is just hanging there for the moment), now, everything works perfectly wth no feedback and all triggers work also.

So, I am guessing it is the actual 520T module (I have ordered a replacement to test)  Once I ge the new one in (today), I will post the outcome, but I am hoping that is it. 

for now i am still sticking with my first diagnosis. if you are useing a DVM to read voltage, it may not show the extreem dip in voltage on the initial hit of the starter on it's numeric scale as well as graphing display might.

i do have another question though. where is the red wire on the 520t getting its feed from?

Ok..   The plot thickens.

First off, red wire is getting it's voltage from the thick black off the main J/B

Now, I went out to change the 520T module.. DEAD.. Alarm was completely dead.  While checking it out, I noticed that the

15 amp fuse on the red wire going to the 520T module was blown.

So, first thing, test started car..  started right up, no issues.  Then I removed the old 520T module and re-connected the blue wire to the harness and plugged in the new module.  Then I replaced the 15amp fuse and tested the alarm.  No issues. arms, dis-arms, triggers, passive arms, car starts right up AND after I shut the door and either arm manually or passively, I DO NOT get that second chrip, just the arming chirp and no "trunk" display on my remote.

Thing that concerns me is that the 15apm fuse was blown.  Any ideas?  remember, I upgraded the 12v .7 Ah battery to a 12v 7.0 Ah battery, but that should not matter, 12v battery is a 12v battery, amp hours only keep it running.  Could the 520T module been screwed up and blew the fuse?

Thoughts?

that blown fuse might be a byproduct of the failed old 520t.

if it all is now working as it should, maybe the fix was the new 520t module. time will tell.