LC Intermittent starting and no power problem. (1 Viewer)

[mikeyd]

I need some help guys.

I installed @medtro's EFI bypass kit in my '00 LC a couple of years ago after I had intermittent starting issues, which was solved with a 30 amp fuse (so I bought @medtro 's kit).

This week my LC failed to start 2x in the AM for my daughter before school. The first time I suspected this kit was to blame, I removed the fuse cover and made sure the wires were all seated properly, then the LC started.

The second time it happened, I noticed there was no power to anything - no power seats, no power locks and so on. But, I checked the kit wires and it started. We just moved and are still unpacking, so I accepted this as a solution and put further investigation on hold.

Today no start. No power. I checked the battery and it read 12.6 volts. I have a 6 mos old Interstate AMG that is recommended for the Slee battery tray.

After my charger showed the battery was fully charged, I tried again. I heard the starter clicking, but it did not turn over the engine. After several attempts, I put the charger back on and went inside to do some work for my job.

I just went back out and the battery read 13.1 volts. Key in the ignition and nothing. No power to anything.

What electrical problem would cause me to have power sometimes, but other times the LC is dead in the water - despite having a battery with 12.6 to 13.1 volts?

I am open to suggestions.

Thanks.

 

[Trunk Monkey]

Trying jumping it from another vehicle. Sometimes "good" batteries aren't.

 

[mikeyd]

Trying jumping it from another vehicle. Sometimes "good" batteries aren't.

Roger that.

Jumper cables are in a box somewhere at my new place or in the storage unit. But yes, that is something I have not tried yet and will.

 

[medtro]

I installed @medtro's EFI bypass kit in my '00 LC a couple of years ago after I had intermittent starting issues, which was solved with a 30 amp fuse (so I bought @medtro 's kit).

This week my LC failed to start 2x in the AM for my daughter before school. The first time I suspected this kit was to blame, I removed the fuse cover and made sure the wires were all seated properly, then the LC started.

Checking to see if the kit is failing. Did the engine crank when the LC failed to start 2x? If the engine cranked, did you have flashing security light while engine cranked? How is the connection to the fuse slot? You may want to connect it to the battery if the connection is loose.

 

[mikeyd]

Checking to see if the kit is failing. Did the engine crank when the LC failed to start 2x? If the engine cranked, did you have flashing security light while engine cranked? How is the connection to the fuse slot? You may want to connect it to the battery if the connection is loose.

I had a mixture of nothing, clicking, and cranking.

 

[mikeyd]

After further investigation, I am chalking this up to a bad battery. Started right up with jumper cables. Voltage at the battery while running was 14.61.

For the record - I installed a new Interestate 31P-AGM7 in October 2021.