Lights Flicker

GTE

Hello!

My car was broken into a couple of years ago and since then, when cold, the dash lights flicker. I never noticed it before, but I was looking for issues after the break in and I think the wiring loom was damaged when the radio was forcibly taken out.

Recently, I have noticed the front headlights switch off when the car jolts, such as a gear change under heavy load - anything enough to jerk the car forward and back. It is just a flash, as in the same time as if you were flashing your main beams for whatever reason. During idle, I can notice a much less pronounced flicker of the headlights with no obvious pattern off the car or wall in front. Thankfully, at this point in time it does not take away from a constant beam. What I mean is that there is no danger of me losing the lights for any extended period of time.

Finally, I can not remember when this started but when the key is in the ignition and the various lights are on, I see the battery flicker off for an instant every few seconds.

Could all of these be related? I find it unusual that the headlights would be flashing as result of the possible wiring loom damage from the break in unless some kind of short is messing the whole car up? I can not see any obvious link between the dash flickering and

I could put up with the flickering dash but the headlight issue is getting a bit more pronounced as the cold sets in (could also tie in with more night time driving so I notice it more).

EDIT: Now that I think of it, when I switch the indicator the headlights can sometimes flash off but that seems more like a fault in the stalk rather than for anything else I mentioned.

No other faults reported.

Thanks!

GTE

It is hard to say if it is getting worse but it is no better. Would anyone recommend a good automotive electrician that could help find the problem? That is, if there aren't any things that I should check myself beforehand.

Thanks!

visual

Sounds very much like a bad connection

You could check the battery connections and negitive strap to body

But it could very easily be damaged wiring from radio theft Unless you have wiring diagram, volt / multi meter and prepaired to pull the dash apart then your checks will be limited.

GTE

The battery connections are fine. Though, there is a white powder on the top side of the battery. Around the middle of the battery, mid way between the two connections.

GTE

Battery measures 12.7 volts when the engine is off and 12.5 when on.

The fast flickering of the headlights goes away when revs are raised. This does not explain the brief switching off of the headlights when driving and a jolt of the engine occurs.
The tension of the belt at the alternator is good and stiff.
I don't know where else to look in the engine bay, not too sure where the neg strap is/goes.

I think the interior dash light flicker is down to a dodgy dimmer switch, which could have been yanked by the loom when the car was broken into. Moving the switch causes a lot of flicking from low to high brightness. I don't mind bodging the switch so full brightness is used at all times. I guess that would be a good test to rule that in or out.

visual

Clean the battery terminals and battery poles so they are both spotless. Use a fine sand paper or battery brush also clean top of battery with a cloth.

Voltage with engine running should be close to 13.8 volts

The dimmer switch should only affect dash lights and not cars low and highbeam lights.

GTE

visual wrote: »

The dimmer switch should only affect dash lights and not cars low and highbeam lights.

Aye, this is why I am thinking I have two separate problems which have a similar symptom. But again, I will have to bodge the dimmer switch to be sure.

I will give it a clean tomorrow, though I can not explain the voltage differential that I seem to have.

rex-x

Sounds like your alternator might have seen better days

GTE

I am hoping I just need to tighten something though. Time shall tell.
As per my other thread here, the car is due a service soon and I want to give it a good seeing to in all aspects.

GTE

Hmm,

I wasn't very happy with my technique for using the multimeter the other night.

Just now, I used the crocodile clips on the battery.

Engine off: 12.5 volts
Engine on: Idle 12.7
Engine on rev at 1800: 13.8
Engine at idle after revving: 13.5ish

Across the whole connection, never under 12 and never over 13.

I suppose I am still on the low side of normal with those figures.

This reinforces what I notice where the headlight flicker goes away when revved. Does not explain the lights switching off when jolted.

The dimmer dash lights, which flicker regardless of revs, is more complicated than I anticipated and a bodge is not possible. I could get another dimmer module but to be honest, there is no flickering when the engine is off so I am not convinced.

With the battery terminals clean and all looking well there, where are all the other things that I should check for tightness in the engine bay? Once I rule out those, I can be sure that something is up with the loom under the dash.

GTE

So I tried to bridge the connections to bypass the headlight dimmer switch, and couldn't figure out which ones I needed.

I posted this on the UKMKIV forum and got info on what connections and sure enough, the dimmer switch caused all my dash related problems. The vibration of the engine was enough to cause the switch to go mad.

Though, my headlight issue remains.

I have LEDs in the interior roof lights and as I was just working in the dark, they were on when I started the engine and they are flickering like a b***h. I guess the LED reaction to low voltage is more obvious.

Anyway, one down, one to go.

GTE

I have been sloppy with thread starting between here and the main forum as the longer things went on the less DIY seemed appropriate but just to close up this thread, I had a chance to take the battery out and check the grounds which looked very healthy. Just a clean with a brush was needed.

In the link below is another thread I made but has pictures of an electrical connection that is looking worse for wear. I taped it up for now and the headlights have stopped messing around.

http://www.boards.ie/vbulletin/showthread.php?p=87813112

Fingers crossed