I have to unplug my battery ground wire to keep all the lights from flashing in my car even while it's off and the key is out of the ignition.

THE CARS BATTERY MUST NOT BE INSTALLED (CONN.) BACKWARDS EVER. OUR JUMP STARTED BACKWARDS.

NOT SCANNING THE OBD2 PCM IS HUGE FAIL. !!!!!
IF THE CAR HAS THE FACTORY IMMO (IMMOBILIZER )
YOU CAN NOT SWAP THOSE PARTS ,DIY, BY DESIGN.
YOU FAILED TO CHECK ALL FUSES
OR SWAPPED PARTS WITH BATTERY NET LUG NOT CONNECTED, IS IT MUST BE. DOING ELECTRIC WORK.
IS THIS A USA CAR, NO COUNTRY TOLD
AND THE PCM;S ARE NOT THE SAME
NO ENGINE TOLD SAME ANSWER
THE IMMO LAMP ON THE DASH IS MARKED "SECURITY"
IT MOST NEVER FLASH WRONG PER USERS GUIDE.
NOW THE WORDS IN THE BOOK

If any of the following indicator conditions
occurs, contact your Toyota dealer.
D
The indicator light stays on except
when the theft deterrent system is set-
ting or activating. (See "Theft deterrent
system" on page 30 in this section.)
D
The indicator light does not start flash-
ing when the key is removed from the
ignition switch.
D
The indicator light flashes unsteady.
THE LAMP IS HERE, AND CAN NEVER BE IGNORED.
SOME CARS KEY OFF KEEP POWER UP FOR 10 MINUTES;.TO SOME THINGS, RADIO ,ETC.
I THINK NOT THIS CAR.
immo LAMP. IF GLOWS WRONG THERE WILL BE NO ENGINE START, (CUTS SPARK /FUEL ) OR MORE.,
THE BATTERY MUST BE FULLY CHARGED
OR COMPUTERS ON BOARD WILL MALF/
AT 10VDC MOST DO. OR LESS.
CRANKING VOLTAGE IS 11V TO 12V.
THE SHOP MANUAL SAYS STEP1 DOING SERVICE
KEEP BATTERY FULLY CHARGED OR HAIR GETS PULL OUT FAST AND BLUE WORDS FLY.

Make sure your Battery is fully charged. A partially charged Battery can make the alarm system malfunction. Also, make sure the
regulator is charging the Battery. Some key alarm systems can
and will drain your battery if the Car is rarely driven especially
if there is a ignition kill switch wired into the system. The key alarm
system on my Mercedes 560SL used to drain my battery whenever
I didn't drive the car enough.

try to do a hard reset. remove battery cable for 2 minutes and reconect. if it does not work try starting with a spare key. if you dont have a spare key then you have to buy a reprogram a new key. this is something only the dealership can do. well it depends where you are

check the alternator and check for a short or ground a wire may be touching the frame you may want to check the engine computer module

use ohm meter to check ground to pos cable to starter If 000 check for ground wire on starter it should go to starter bolt. voltage reg stuck open Unplug ignition module check battery if still sparking not module.

Hello it is not easy to use a computer with a 4 year old constantly trying to get your attention.Anyhow i said disconnect your battery wait 5 minutes to reboot the computer i have gone through your situation a dozen times if it doesn't start it should trip your check engine light and you will be able to scan and retrieve keep me posted.John

For starters, make sure that you don't leave any electrical components on. If that is not the issue then check the cars wiring. Have an electrician check it for you. My hunch is that there is some wiring somewhere that is not properly grounded and/or there is a short circuit somewhere. These two things will lead to battery drain especially since removing the key from the ignition does not turn all the electrical components off. (ex. the headlights, horn, tail lights, brake lights, interior light may be turned on even without the key.)

unplug connector at ignition switch, bridge terminal 30 [battery power] on connector and terminal 50 power to starter solenoid. engine should turn over. plastic ignition switch can wear and not make contact. at times the lug on ignition barrel that turns the switch breaks off.

Hi,

I would interpret your post of "engine won't turn over" as it would not crank. Basically, cranking is accomplished with the starter motor, however, there are other components that could likewise affect the cranking:

• battery, battery terminals, battery connector, battery ground to engine;
• starter motor, bendix, starter relay;
• ignition switch, ignition wiring/harness/connectors.
  

In some instances, failure to crank could also be caused by:

• immobilizer/alarm system;
• automatic transmission not in park or neutral or gear position switch/sensor misaligned/malfunctioning.

Hope this be of initial help/idea. Pls check above itemized parts, post back how things turned up or should you need additional information.

Good luck and kind regards. Thank you for using FixYa.

Try removing the alarm system relay, some car alarm has also a fuse on the alarm that you can remove.
Many car alarms unlock by inserting and turning car key while you connect the battery.