1999 Suburban Electrical & Start Problems

[tumper93]

When you checked for a parasitic load with a test light or meter you have to wait for up to 10 minutes for all the modules to go to sleep! If you have onstar then the light will get bright every 7-minutes I believe it is and then go back out. Trying to determine if you have a draw with a test light on a newer vehicle is a bad way to do it because you don't know what the resistance value of the bulb and wiring to it is. You need to put an ammeter and check to see if it is below 32ma after everything goes to sleep. Test lights can be all different amounts of resistance from one to another and cannot be trusted and can mislead you to a problem because of that low resistance in one as to another. We have had a lot of problems with BCM's around that time period, more in W bodies than trucks but I have had more than a few in trucks also. The clicking is most likely a faulty internal relay of the bcm, the draw may be within limits but could also be caused by the bcm. If you have to replace the bcm you must have it programmed after it is installed, most of the time based on the build your vehicle may not start after it is replaced because of the passkey theft deterent system. I would suggest taking it to the dealership and let a tech diagnose it. Are you near High Point, NC? If you are I can give you the address to the dealership I am at and we can see what is going on.