Possible voltage regulation issue?

[HEXEM]

Hi all,

After getting my car back from the Holden dealer (3 weeks and 2 new motors!!) All seems to be running nicely.

One thing I have noticed is the voltage meter on the dash (the 3 window red LED type) seems to be a bit erratic. By erratic, I mean the voltage will climb to 15.3volts after starting the car then climb down contantly to about 13.2volts and level off somewhere around 13.9, this will occur any time of the day and after any lenght of driving (5 to 30min trips). This has only be noticable since they installed the new motor.

The other thing I've noticed is when its sitting around 13 volts and I then drive off the voltage will increase to back up to 15 (based on engine revs etc) and eventually settle back. Thinking that I had a possible loose connection on the battery I reseated them and made sure they were tight. I also ckecked the connections on the alternator. While this was occuring when parked in the basement at work and the engine idling my headlight would periodically flicker (bright then dim etc).

I went out to see my dealer and spoke with the tech and he said that its normal for the voltage to change. I understand this as the BCM controls the voltage charge rate etc, however I have never had issue with flickering headlights or such erratic voltage variances.

I had them SPS the BCM to change the charge rate from standard to Police mode. This had no immediate effect. Last night I was making sure earth connections for the engine harness were tight and also the large black plastic junctions for the main wiring harness (one at the firewall and the other near the engine bay fuse box).

This morning things seemed a little more settled. No headlight flickering or erratic voltage readings. When I took the car out tonight and the headlight were on the voltage crept up to 15.4 volts and after a few minutes of driving it dropped back to 14.2.

I am hoping that the BCM or alternator is not on its way out. There are no other electrical issues I can tell (such as dash light dimming, indicators not turning off etc).

Other that have a MY9.5 or MY10 with the same display could you tell me if your voltage readings are up and down like a yo-yo in quick succession? Or others that might be able to give me some options to look further into?

Cheers
Phil

P.S. First up I had thought it might have been a low voltage on the battery after sitting for some time. So I gave it 48hours charge on the C-TEK 7000 calcium charger.

[nikvyss]

Could be the reg on your alternator causing the problem mayb take it passed a auto elec for a second opinion

[steve_t]

Dunno about the flickering headlights but the voltage changing sounds normal

[HEXEM]

Could be the reg on your alternator causing the problem mayb take it passed a auto elec for a second opinion

No reg on these alternators. Charge and behaviour is controlled by the BCM.

[nikvyss]

Oh ok my bad have u had any luck with finding the problem yet? Best of luck with it

[tekneak]

GDay Hexem,

I had the same issue with an earlier model (07 VE SSV), and I remember putting up a post on it too (here somewhere).

Before my issue started, the voltage reading was pretty good, showing around 13 Volts during normal driving, and rarely moved.

I started to notice it started to move anywhere from 12 through 15V during driving. I also noticed my headlights were flickering if voltage dipped under the 13V level. They would still flicker over 13Volts too. These readings were on the old LED displays. It was only when the car was reading 13V that everything seemed to appear normal.

Took it to Holden, got the usual "oh its operating as per normal", then 2 weeks later my alternator warning message came up on the dash. Replaced the alternator under warranty, and all good.

I would just check out the behavious of your headlights and even the speed of your windscreen wipers. As the voltage changes (up and down) you should see some difference in the headlights and wipers, and could mean you may be in for a new alternator.

Best of luck!

[HEXEM]

Thanks tekneak for the info. I'll keep it in mind.

As an update the dealer could not recreate the fault (as usual) however they did check the headlight globes and noticed one had bubbled. Apparently they have seen this issue once before which caused all sorts of electrical gremlins.

They replaced both globes in the projector headlights and the voltage variation ready appears to be operating normally for the last 3 days. They were trying to tell me that is could be the BCM, however there are no other strange things happening with the electric.

The instrument lighting is perfect and was not flickering which if it was could indicate a BCM issue.

Thanks all.....

Cheers
Phil