NO CRANK, NO START!!!!

[rj investment s]

For a while I’ve been having problems charging. If I don’t drive my car for about 5 days I will have to jump it off. As long as I crank it every 2 days when I don’t drive it, it’s all good. I remember before I replaced my battery this past winter advance auto was saying my alternator was good when they put it on the scanner. So now I haven’t drove my car since the 1st of March. So now here is the problem after about 6 days of not starting my car I tried to crank it and the battery was weak from the sound of the engine turning over and it went dead and started clicking, then nothing.Took the battery to get it tested and they told me it was good just a little low but should have cranked my car, so I left it with them to charge it up. After fully charged and tried to crank it again, and nothing, then I hear relays clicking in the fuse box under the hood. I didn’t check my fuses in the beginning but went and bought a starter relay from GM. Still no crank, jumped the starter from fuse box and turned over, but still thinking maybe it had a bad solenoid so I bought a new one and put it on. Turned the key and nothing, so I started checking fuses and #5 ecm blown. Replaced fuse and soon as I put the key in the switch it blew. Put in another fuse and turned the switch to acc before starting and blew another one. Left the key in on position and replaced it. The car cranked and ran for a minute then shut off. Checked the fuse and it was blown. Cleaned the cable that’s grounded to the fuse box and runs to the alternator. Took the alternator off and cleaned that end. Also cleaned the thick cable that is in front of the fuse box and connected to the side of the engine block. Still same problem, ordered a fuse box waiting to receive in a couple days. Any ideas would be helpful before I try the fuse box and if not fixed buy a ECM

[Mouse330]

I'm thinking you have an internal short in the alternator. what I would do is disconnect the regulator connector (two wire) at the alternator, put a new ECM fuse in the UFB and turn the key on, Check if the fuse is blown. Also check for 3.5V or greater on the brown wire KOEO. GL

[rj investment s]

Ok thanks I will give that a try this weekend

[rj investment s]

Originally Posted by Mouse330

I'm thinking you have an internal short in the alternator. what I would do is disconnect the regulator connector (two wire) at the alternator, put a new ECM fuse in the UFB and turn the key on, Check if the fuse is blown. Also check for 3.5V or greater on the brown wire KOEO. GL

No it didn’t work as I unplugged it, it still blew. Took the alternator off to get it checked and it passed. But funny thing I bought a used fuse box from Knox Auto parts and it didn’t blow but I checked the fuse with my test light and didn’t get a signal. But I took the top of the used one off and put my test light to the harness where the fuse goes and my light lit up. Put my old UFB back on and same problem as before. The guy at the part store told me I should take off the hard wire that goes to back of the alternator and see if it blows. Don’t know if the UFBs are just plug and play or maybe I bought a bad one?