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.

[bretcopsey]

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.

Good to know! The test light is about all I have at my disposal besides the volt guage on the dash. If I could get the darn thing to start I'd be happy. I just hate the thought of adding a tow to the cost of taking it to a shop! I'd also take you up on your offer, but I'm in SW Ohio.

I did just remeber that the heater switch was acting up recently as well...HMMMM

[bretcopsey]

I've not had much time to look at this lately, but just spent some time tonight and I'm starting to feel like I'm up the creek here!!

The battery was re-tested tonight just to be sure-it's only a few months old. The new starter didn't make any difference. I hit the key and the volt guage on the dash reads about 10.5 volts, you can hear the starter solenoid click and that's it. Same place I was when this all began. What really has me puzzled is that this all started with a radiator repair. I rer-installed the radiator and filed with coolant. Started the engine and bled out the air. There was a brief spark at the positive terminal, but I didn't think anything of it at the time. I shut it off and went to start it again two days later, nothing-where I still am today.

I'm thinking about replacing the battery cables, but would hate to go through the effort with no results. I'm also wondering about the current setup, which I will post some pictures of shortly.

[bretcopsey]

Here are some pictures of the current battery cable situation. It looks to be aftermarket, possibly part of the remote start system I removed?

There are two cables at the positive terminal. Onegoes to the starter, one to the terminal mounted on the fan shroud. Then thee is a cable that runs from that same terminal on the fan shrous to the alt. The other terminal's cable runs over to the rear of the underhood fuse box that's near the brake booster.