Electrical gremlins

[myksomerville]

Electrical wizards, a bit of help?

2011 VE SS Series 2 Sedan.

Last weekend my cruise control stopped working while I was driving and would not restart. When this happened, I noticed that my airbag control also restarted - this is wired to the accessories circuit, as far as I know (I will check with the installer). All accessories still working, and the car starts and drives fine.

Then last night, I found my headlight halos would not work. These are on the park light circuit.

Any ideas what I should be looking for? Checking the Haynes manual, these are all independent circuits - ECM, accessories, and park lights - yet all seem to have faulted at the same time.

I've had a suggestion it could be the clock spring, but I can't see how that would affect the park lights. Maybe ignition barrel?

 

[Fu Manchu]

Check charge circuit voltages.
Check battery voltage
Load test battery
Have battery health checked

Disconnect the halos and see if fault persists.

Low voltage conditions can see the ECM ration available voltage to keep more critical systems working, like the engine.

 

[myksomerville]

Check charge circuit voltages.
Check battery voltage
Load test battery
Have battery health checked

Disconnect the halos and see if fault persists.

Low voltage conditions can see the ECM ration available voltage to keep more critical systems working, like the engine.

Long post warning...

So I checked the battery (Century Ultra High Performance Din65lhx-Mf, New 11/23), was at 12.5v. Tested battery, and it reports condition bad - replace (health below 10%).

Starts and runs fine, no problems at all but I obviously need to replace the battery. I haven't run a charging system test as I need a 2nd person (one in tester, one on the throttle). I suspect a bad alternator, however I have a couple of questions. I'm not an electrician, so these may be dumb questions - apologies in advance - but I m learning as I go.

* I have an airbag system that is wired directly to the battery via a fuse, but is operated on by the accessories circuit. The control unit is constantly illuminated so is drawing *some* power at all times, however little (I'll be measuring this tomorrow). Would this, over time, damage the battery? The car is a weekender at best so only gets run every week or so.

* Would the 25% underdrive have any role to play in either alternator or battery failure?

I fully charged the battery, it failed the battery test again, and halos still don't work.

I disconnected the battery for 10 minutes and tried again, still no halos on a fully charged battery so I don't know whether the ECM is managing the power (would a VE even ration power to the park lights?

I tested the battery again, it had dropped to 12.5v/50%. I'm charging it again before further testing with the airbag power disconnected tomorrow.

I should point out that there are no warning lights and no codes found in the OBD2 scanner.

 

[Fu Manchu]

Yes the under drive will play a part in poor battery voltage.

If you suspect the alternator as the problem, you should be of the mindset to prove the fault.

I’m going to suggest a further hypothesis that the under drive is causing the alternator to under perform.

What is the alternator output like?

 

[myksomerville]

Yes the under drive will play a part in poor battery voltage.

If you suspect the alternator as the problem, you should be of the mindset to prove the fault.

I’m going to suggest a further hypothesis that the under drive is causing the alternator to under perform.

What is the alternator output like

Tested the charge system with the airbag system disconnected:

Loaded 14.42v
Unloaded 14.27v
Ripple 18mV

Result: Pass

No difference in the results with the airbags connected.

The airbag controller runs a Bluetooth connection that is always on, so obviously draws some current but negligible.

I'm off to replace the battery, not sure what to do with the alternator - upgrade to 140A? Keep it as is?

 

[myksomerville]

Took the battery to Supercheap to return as it is under warranty.

Their tester says that the battery is fine. Mine says it needs to be replaced. The indicator on the battery says "recharge" although the battery is at 12.7v 93%

Im confused. Maybe my tester (brand new, SP Tools) is faulty?

Taking it to Century Batteries tomorrow...