1snake

I guess what threw me and everyone else there was:

1. Brand new everything including the battery.
2. Battery was fully charged and working perfectly when I disconnected it.
3. Battery indicated to be fully charged when I hooked it back up. Why wouldn't it be?
4. Power at the engine side of the firewall plug but none inside the car, not even enough to light a dome light, even an almost dead battery would still light one up.

Logically, everything points to the firewall plug.

It obviously was in the back of my mind somewhere that the battery might be the issue or I wouldn't have brought a know good battery back with me even though the one in the car was "known good".

Thanks for playing.

Jim

steveale

Jim,

Don't let the battery company know about your secret or the warranty is void....

wmf62

Jim
that just doesn't make sense to have power on one side of the 'plug' and not the other///
Bill

Ironcross

check and clean the ground connection from the battery to the frame....many owners don't even know where the connection is...{short cable from battery to frame under or near the drivers seat}

1snake

The reason it was like that was I checked for power on the engine side with the door closed so it read 12.9 volts but when I opened the door, the dome light put a load on the battery causing it to read zero so there was no power at the fuse box. Had I left the door open and gone back to check the engine side again or even directly at the battery, it would have read zero.

Jim

1snake

Not on a C-2. The neg. cable goes directly to the outboard starter bolt. The answer is in post #34.

Jim

wmf62

, just dumb luck/stuff happens...
Bill

1snake

Now you understand why it was so hard to figure out. Something as small as a dome light caused the battery to temporarily read zero, otherwise it read fully charged even though it wasn't. A lead acid battery would never do that, but then again, the manufacturer says an AGM battery won't do that either, but it did, to me, on a hot day at a car show. Lucky me.

Jim

wmf62

i'd have tried to check it with a 12volt test light, so maybe it would have acted like your dome light and i wouldn't have shown a circuit; therefore by dumb luck, i'd have said 'battery'...

or not...
Bill

1snake

In hindsight, that would have shown the problem IF combined with the use of a volt meter because the test light wouldn't have lit up making you think it was broken especially when the volt meter shows 12.9 volts. You would then have had to check the test light for proper operation on another car. Then you would start to see the problem. Confusing as he11. I prefer to use a volt meter because that will tell you the exact state of charge of an AGM battery. 12.8+ volts fully charged, 12.6 -12.7 80 %charged down to 12.3 which would be almost discharged but would still brightly light up a test light.


Jim

goodwood67

Buy a new set of battery cables.

1snake

They are new. The issue was with the brand new battery. Read post #34 where I explained it all.

Jim

Westlotorn

Thanks for sharing, I am not a fan of AGM batteries, although I have read many advantages, My wifes X5 now 4 years old has an AGM, she told me her air conditioning would not work, I went at it trying to find the source. I could find nothing wrong, I tested the battery voltage and had 12.5 and thought all was good. Did some reading on the INTERNET and found out the Smart Vehicles today see a voltage drop and start shutting off systems to keep the car on the road, one of the first to be shut down was the A/C system to protect the battery power available. After wasting several hours I ended up buying a new battery and all works well again. The X5 starts thinking you are in failure mode when you get down to 12.5 volts. I really don't need a car that thinks for me, it really pisses me off when I try to diagnose using old school skills. I feel your pain and I am glad you figured it out. This will be a memorable car show for you, a reason to laugh over a beer in future.

1snake

That was the point of my post. For us old school guys, nothing made sense so think outside the box. Absolutely no test or history of the vehicle/parts pointed towards the battery. As far as the beer in the future, I've been drinking heavily since.

Jim

EDinPA

This is why I have a battery load tester. The voltage reading at the battery is nice to know but is a not a guarantee of a batteries health.

Matt Gruber

had a similar failure. battery has rivets connecting each cell to the next. rivet broke. current flows thru acid only, so tiny bulb dims. Took off caps. i stuck in a screwdriver (dangerous) while i tried to crank. wiggled it and it fired right up.