1999 silverado security light no start

Help Please, A week ago I lost my lights on my 99 silverado, traced it to the harness going into the turn signal, cruise , windshield wiper harness. Bought the new part and when I was taking off the old one to put on the newone my alarm started going off? I quickly placed it back on to stop the alarm, then I unhooked positive cable on the battery to disable the alarm so I could replace the lever and harness. after hooking the battery back up the security light now stays on constantly and the truck cranks but shuts right off? Been reading up on the passlock thing and the 3 cycle ten minute on?off with the key, tried it twice to no avail! I do not have an original key and my key fob no longer works, at my wits end here and don't have a lot of money to take it to dealer, any ideas would be helpful thx in advance. ps have checked all fuses, replaced positive battery bolt, also aftermarket radio does not turn on now?

explain "NEW PART" . give part number and where purchased. also anything disturbed/removed/wiring etc.

Sorry, I had to replace turn signal... controls the wipers, cruise, brights, the harness that is or was connected to it had 2 wires pull out of it probably explains the loss of the headlamps and the brights. I first attempted to pull off the molex connector to see if I could place the wires back into the molex, no go on that so I ordered the part online, dealer wanted 458.00 for it. Couldn't afford that so bought a replacement for 150.00. I feel like by unhooking the pos. cable to the battery for about 20 hours put my vehicle into lockdown mode with the factory security. Security light stays on constantly, and it shuts down as soon as it cranks. I guess I am wanting to know if there is a way to reset the codes for the anti theft? As mentioned previously I have tried the cycling the key on and off for 10 min. x 3 and that would not fix it.

Part was purchased online from race pages, I unhooked the battery cable. positive , because when I went to take the part off the truck the alarm started to go off. Part no. is arbt505803, I used the gm part no. given to me by the dealer and they crossed it to this part. I have a 4.8 L with a manual transmission.

Two things:

1. Is this truck the Old Body Style or New Body Style?

2. Whenever doing electrical work the NEG battery cable should be disconnected not the POS.

Part was purchased online from race pages, I unhooked the battery cable. positive , because when I went to take the part off the truck the alarm started to go off. Part no. is arbt505803, I used the gm part no. given to me by the dealer and they crossed it to this part. I have a 4.8 L with a manual transmission.


well the new body style security relearn is like this

ignition on,turn to crank then leave in the ignition on,security light is on solid for about 10 min . when the light goes out,turn key to off wait 5 sec. then turn ignition to on, move to to crank,

leave in ignition on, when security light goes out 10 min turn key to off, wait 5 sec. then turn to ignition on , turn to crank,leave in ignition on, when security light goes out, key to off wait 5sec, turn to ignition on , turn to crank, leave in ignition on

repeat this again.now thats 30min time. then it should have relearned.

if not then you must check that those 3 wires to the security sensor in the steering column are not damaged or the connector messed up.connector c201 c4 orn/blk ground ,c2 red/white 12volts , d3 yellow to the BCM.

as you now know with the key not in the lock cylinder you have power in this steering column .because you messed with this under power your lucky the air bag did not wack you . always when working with electrical devices remove the negative connection at the battery. this is always removed first.never remove the positive first.

it is possible the BCM got damaged or the BCM needs reprograming and or bcm failure codes pulled to further get down to the exact failure .

too late to tell him that now about disconnecting the battery but unplugging the multifunction switch should not have set the alarm off. are you sure you didn`t accidentally pull the wires loose from the RF receiver on the ignition switch. tere is something else you can try turn key on if security light is on or flashing just leave key on until it stops flashing or about 45 minutes to hour then try starting. make sure everything else is off and door closed don`t want to loose battery if need be put a 2 amp charger on during this time.

[quote=matthew24u;6993079]

too late to tell him that now about disconnecting the battery
quote]

Its never too late. thats because a few hundred people will read this and know never to do this .

ya it is new body style, and I am gonna try the relearn tomorrow, the new turn signal/windshield/cruise lever came with all new wiring, but I will inspect the wiring going to the ecm tomorrow, pretty sure I know which this is. Also none of the ignition wires were touched or damaged. Thanks for the advice on the battery disconnect. My son did tell me today he was trying to help get the original harness off by easing it off top ad bottom with a skinny slotted screwdriver and may have hit some of the connectors on the molex? possibly shorting something out?

ya it is new body style, and I am gonna try the relearn tomorrow, the new turn signal/windshield/cruise lever came with all new wiring, but I will inspect the wiring going to the ecm tomorrow, pretty sure I know which this is. Also none of the ignition wires were touched or damaged. Thanks for the advice on the battery disconnect. My son did tell me today he was trying to help get the original harness off by easing it off top ad bottom with a skinny slotted screwdriver and may have hit some of the connectors on the molex? possibly shorting something out?

since it is NBS I have the wiring diagrams OEM if you need further info.

post back how this worked out.