DEI 507X with 515R Battery Siren

Everything working OK, put car in garage without doing anything with alarm and next day, turned off 515R to disconnect battery to change a cable and reconnected battery. Now car will not start and believe 515R is the issue. What can I do to fix this: - Whether 515R is on or off with key, try to crank, get click at starter, voltage across battery stays at 12.6v (doesn't change) and there's no voltage to entire car, no headlights, no horn etc. - Disconnect/reconnect battery and have voltage back in car - Rinse and repeat = no start The reason I believe the 515R is the problem is because one time after it would not start and disconnect/reconnect battery, turning the 515R on, it went off thinking the battery was disconnected. Off and back on several times and same thing. Turned it off, disconnect/reconnect battery and chirps when 515R turned on as if all OK, but car will still not start. Battery tested OK under load, 12.6 volts not under load, starter/solenoid removed and tested OK. Desperately need help please! What can I do to get car started? PS - Don't know if this has anything to do with it, but 515R siren getting weaker and weaker as if batteries are going bad or are not charging.

You haven’t mentioned what you have for a vehicle. I’d start by checking the bigger fuses under the hood in the power distribution panel. Maybe something blew when you changed the battery.Steve G

84 El Camino, TPI, all custom, no power dist'n panel, only the 3 wires from starter solenoid (1=ign switch, 1=lights, 1=fuel pump relay). Old Viper 507x alarm system. Alarm works as is should in every function except remote start which has not been tested because of the current issue. Checked all fuses and fusable links and all OK. The only issue is the apparent alarm starter lock out somehow related to the 515R. Need a bypass technique or how to remove without causing another problem. Is there a procedure to reset this alarm system aside from disconnecting the battery?

I'd check the H3 10 pin Remote Start connector coming from the 50.7x shown on the bottom of page 6. Try to temporarily jumper together the violet and green wire to see if that allows the starter to engage. https://www.directeddealers.com/manuals/IG/Viper/N5702_2009_09%20web.pdfSteve G

iskidoo wrote: I'd check the H3 10 pin Remote Start connector coming from the 50.7x shown on the bottom of page 6. Try to temporarily jumper together the violet and green wire to see if that allows the starter to engage. https://www.directeddealers.com/manuals/IG/Viper/N5702_2009_09%20web.pdf

Will do & thanks for manual. It's slightly different than what I have for the 50.7x.

SOLVED! The issue was a bad ground -- battery to block. But a most unusual one. The test that brought it out was disconnecting battery ground cable, Neg DVM lead to neg batt and pos lead to disconnected cable. Bingo, 0.2v. All grounds good except at the block. It was more than tight and not corroded. But, after disconnecting and inspecting the cable end, it was not truly flat where attached to block. Not bent, just not really flat even though a star washer was used, apparently preventing solid contact. But this cable has been this way for over 6 years and has never been touched. Go figure. Filed flat, reattached and it cranked. Thanks again for all the help!