Won't Start When Cold
BF Veteran
Joined: Jan 2007
Posts: 4,631
From: Florida
I am trying to help you figure this out with what you have on hand but I may be getting out ahead of my skis. The reason why that test rig is so useful is because when you close the switch the battery circuit is maintained so everything works as it should and you can cycle everything safely. Then you wait for the systems to go to sleep before you change the switch position and put the meter in-line. The battery connection is never interrupted because the switch is make before break so you don’t wake anything back up. The meter was safely out of he system during the highest load cycles and there are inline fuses for protection. If we abandon that set up there is risk of damaging your meter. As you have discovered an ammeter clamp approach is way easier if that equipment is available.
Some believe that you cycle everything, wait for the truck to go to sleep and then break the negative battery connection and start the process. This is probably the more conservative approach and may get you what you need. The problem is that breaking the connection may wake something up upon power up when the meter goes inline and remakes the battery connection and/or the offending item may go to sleep. The 10a setting and meter cable position would also be the most conservative. If you don’t get that test rig working then this is probably where you should start. The actual GM test procedure is cycling everything with their test rig inline but of course factory techs have much better gear.
George
Some believe that you cycle everything, wait for the truck to go to sleep and then break the negative battery connection and start the process. This is probably the more conservative approach and may get you what you need. The problem is that breaking the connection may wake something up upon power up when the meter goes inline and remakes the battery connection and/or the offending item may go to sleep. The 10a setting and meter cable position would also be the most conservative. If you don’t get that test rig working then this is probably where you should start. The actual GM test procedure is cycling everything with their test rig inline but of course factory techs have much better gear.
George
BF Veteran
Joined: Jan 2007
Posts: 4,631
From: Florida
Then you will be able to do the whole program. Open the drivers door, clamp the light switch plunger closed, remove any under hood lamp, start the truck, turn everything on and off, shut the truck off, wait fifteen minutes and then clamp on one of the battery cables and read the current level. Should be 20 - 85 ma or 0.02 to 0.09 amps. If its over that level, pull and replace fuses until the parasitic current drops down when you pull the offending fuse/circuit. Than we go from there.
If you get good results initially, repeat the cycle a couple of times to make sure you don't have an intermittent problem.
George
If you get good results initially, repeat the cycle a couple of times to make sure you don't have an intermittent problem.
George
Starting Member
Joined: May 2016
Posts: 200
Okay, I just started the truck, cycled everything on and then off. moved the windows, radio, blower motor.....etc.
Then I released the hood, turned off the vehicle and shut the door.
At 10 minutes I clamped around the negative battery cable, I saw as much as .40 on the 60a setting, after 15 minutes I reset zero and clamped the same battery cable and saw
a .14 to .18 fluctuation. I,m assuming that's bad.
I've ordered a new ac/delco starter motor because this one is probably original 96' model equipment. I suspect it drags in very cold weather.
Yesterday morning it was about 12 degrees. The battery was fully charged and all it would do is "click" didn't even try to turn over the engine.
That afternoon, it was 29 degrees and it started right up.
Anyway, that's where I'm at for the moment. Daughter is coming in this weekend so probably not much will get done on the Blazer.
I do appreciate the help though. I just don't really operate well in cold *** weather...lol
Later
Then I released the hood, turned off the vehicle and shut the door.
At 10 minutes I clamped around the negative battery cable, I saw as much as .40 on the 60a setting, after 15 minutes I reset zero and clamped the same battery cable and saw
a .14 to .18 fluctuation. I,m assuming that's bad.
I've ordered a new ac/delco starter motor because this one is probably original 96' model equipment. I suspect it drags in very cold weather.
Yesterday morning it was about 12 degrees. The battery was fully charged and all it would do is "click" didn't even try to turn over the engine.
That afternoon, it was 29 degrees and it started right up.
Anyway, that's where I'm at for the moment. Daughter is coming in this weekend so probably not much will get done on the Blazer.
I do appreciate the help though. I just don't really operate well in cold *** weather...lol
Later
BF Veteran
Joined: Jan 2007
Posts: 4,631
From: Florida
It might not be the starter motor. There are relays, switches, wires, connectors. What is the battery voltage at the battery posts when its clicking and not cranking, thats easy enough to check? Let me know if you want to test further and diagnose or if you just want to replace the starter motor and see what you get.
Ya, that parasitic draw is too high 140-180 ma but its not catastrophic and probably not enough to drain the battery in one overnight cycle. When you leave it for the night do you lock it with the remote (activates the security system and more draw) or the door key?
George
Ya, that parasitic draw is too high 140-180 ma but its not catastrophic and probably not enough to drain the battery in one overnight cycle. When you leave it for the night do you lock it with the remote (activates the security system and more draw) or the door key?
George
Starting Member
Joined: May 2016
Posts: 200
Yeah, I'm just gonna go ahead and replace the starter. I'm pretty sure it's the original. As for the truck, I never lock the doors at night. I live in the county and I'm about 600 ft. off the road.
Usually the worst invaders I have are deer and the neighbors horses...lol
Have a nice weekend George, I'll probably not be online much with my Daughter coming home this weekend.
Later
p.s. I had just removed the battery tender before attempting to start, so is was topped off.
Usually the worst invaders I have are deer and the neighbors horses...lol
Have a nice weekend George, I'll probably not be online much with my Daughter coming home this weekend.
Later
p.s. I had just removed the battery tender before attempting to start, so is was topped off.
Last edited by Graveyard; Jan 27, 2022 at 08:16 PM.
Starting Member
Joined: May 2016
Posts: 200
Afternoon George,
I have some good news. Yesterday I replaced the original starter with a new AC/Delco Starter from Rockauto. It was awful but got it done without too much trouble...lol.
Anyway, the engine spins over much better and when I got home today, I cycled everything and opened the hood. I waited 15 minutes and threw the Amp clamp over the negative battery cable. My readings were fluctuating between .04 and .07 . That's good isn't it? I actually suspected and was hoping that a new starter would correct the drain.
I still appreciate all your help!
Later
I have some good news. Yesterday I replaced the original starter with a new AC/Delco Starter from Rockauto. It was awful but got it done without too much trouble...lol.
Anyway, the engine spins over much better and when I got home today, I cycled everything and opened the hood. I waited 15 minutes and threw the Amp clamp over the negative battery cable. My readings were fluctuating between .04 and .07 . That's good isn't it? I actually suspected and was hoping that a new starter would correct the drain.
I still appreciate all your help!
Later