2012 Edge Strange electrical problem, how do I diagnose it?

[Mike Scir]

My neighbor has a 2012 Edge that kills the battery pretty quickly, I think it goes from fully charged to unable to crank the engine in one or two days. (there is a bit of a language barrier but we usually manage). He replaced the battery 3 weeks ago but no change. He took it to a shop that tested the alternator and they said it was good. 

 

Electrical problem history: 
First he said the interior light would not always go off when the driver side door was closed. 

Then he said an engine compartment fuse blew, I looked it up and it appears to be the #18 40A HVAC blower motor, it looks melted and fused. 

Then he mentioned that he heard a buzzing or clicking sound from the engine compartment fuse box and indicated where he thought the noise was coming from but I didn't find any bad fuses in the immediate area, also pulled several, including a black box that might be a relay, that didn't prevent the next symptom from happening. 

 

This is the interesting part: 

I got a voltmeter and without the + cable attached the battery measures 11.4V. With the + cable attached it oscillates between roughly 5.3V and 4.1V about once per second. 

Does these symptoms make any sense to anyone? While to me, on the surface they appear unrelated (door interior light, HVAC fuse, oscillating battery drain) maybe this all makes sense to someone. 

He said there were zero problems that he was aware of when he purchased the vehicle. 

 

Note: The owners are low income and said if I can simply disconnect problematic circuits but the car will still run normally ans safely and pass smog, they'd be happy with that, if the repair would be costly (more than say $200). 

 

Thanks in Advance,
MIke

Edited yesterday at 04:40 AM by Mike Scir

[1004ron]

9 hours ago, Mike Scir said:

This is the interesting part: 

I got a voltmeter and without the + cable attached the battery measures 11.4V. With the + cable attached it oscillates between roughly 5.3V and 4.1V about once per second. 

Battery appears to be past its useful life.

 

Charge it and then take it to a place like Autozone for them to do a health check on it, free of charge.

 

.

Edited yesterday at 11:07 AM by 1004ron

[Mike Scir]

Thanks, I'll do that. The battery is only 3 weeks old. Is it possible the short was so bad it killed the battery? 

[Mike Scir]

We replaced the battery, my mistake, it was 3 months old (not 3 wks). The new battery measures 12.6V with nothing connected, and 12.2V with the terminals connected. Is that a normal voltage drop for a vehicle where everything is turned off? 

When started the alternator charged at I think over 14V. We're headed to Auto Zone to see if their ODBC sensor says anything interesting. 

...

ODBC said it's not smog ready but there's no check engine light so it may be unrelated, they said run some cleaning fluid through it. That's a problem for another day. 
The keyfob remote stopped working, replacing its battery made no difference, so either the remote sender or the radio in the car is bad. 

...

How's this for a diagnostic procedure:

 - monitor the battery voltage while pulling one fuse or relay at a time to see where the current is going, battery voltage should rise when a current drain is removed. 

 - are there any fuses or relays I should avoid when doing this test, either under the hood or inside the vehicle? 
 

Any suggestions will be appreciated. 

Edited 17 hours ago by Mike Scir

[1004ron]

Not too sure of what's written but it sounds like I was right, a dead battery.

 

While at Autozone have them put their battery tester on it which will display state of charge, CCA, Cranking Voltage and charging Voltage.

[1004ron]

Do a Google search for "how to find parasitic draw on car".

[Mike Scir]

The battery that went bad was purchased from Costco 3 months ago. It died pretty quickly. 
The new battery we installed today is the warranty replacement from Costco. 

I'll do the google search you recommended. Thanks. 

[1004ron]

It takes just one deep discharge to destroy a lead-acid battery, which a parasitic draw will do - thank goodness for Costco's good warranty cover, but they might not be so willing if the replacement is returned in a few days, so best disconnect the battery when the car is not in use until the parasitic draw is resolved.

[Mike Scir]

Thanks, I didn't know that. I have a clamp meter and will start pulling fuses tomorrow, we'll keep the battery disconnected from the vehicle (except for testing) until we find the problem. thank you. 

[1004ron]

Its only recent years that DC clamp meters became available - is yours one of the later models that's DC capable?