Lights dim and then brighten on start up.

[STI65]

My Polo has a couple of issues recently. The latest is happening upon starting it after it has been sitting for a while.
The headlights and dash lights dim and brighten and then repeat for a while until the idle seems to settle. It also has an effect on the A/C fan speed. has anyone else had this or a similar issue and what is it? Could it be that the alternator is on its way out?
Thanks for the help and advice.

[Guest001]

Either that or the battery

[brad]

I'd be cleaning all your battery terminals & earth connections & the connections to the big fuses / relays near the battery. Check the resistance of the cables. There are known issues if you search this sub-forum.

[STI65]

Thanks for the advice guys. I replaced the battery less than 2 years ago. If I clean it should I just use a cloth or are there particular methods and tools to use?

[Guest001]

You can use Baking soda dissolved in water or buy a terminal cleaner from Supercrap for $5 or so

The terminal cleaner is a double ended wire brush that has internal and external brushes that fit over the terminal and inside the clamps

[brad]

they should be shiny. wire brush & fine wet/dry sandpaper is often helpful. terminal cleaner is good but doesn't get heavy corrosion off.

2yr old battery could still be the issue

[STI65]

Had a look and the terminals look pretty clean.

[Guest001]

clean and tighten the earths then

[Paazuzu]

Lights dim and then brighten on start up.

I'd be cleaning all your battery terminals & earth connections & the connections to the big fuses / relays near the battery. Check the resistance of the cables. There are known issues if you search this sub-forum.

+1

I would clean your earth connections as mine used to do this when it had some electrical gremlins.

[AALocksmiths]

+1 for a battery. Even though its only a couple of years old it could still be playing up, especially if there are other electrical issues like the battery being drained constantly or the alternator not charging it properly.

I think it would be worth getting the battery tested and check that the alternator is putting out enough volts. Start with that ( as you can generally get them tested for free) and then work back from there.

[Stuwey]

Dead cell? Got a multimeter?

[brad]

Dead cell? Got a multimeter?

+1 for a battery. Even though its only a couple of years old it could still be playing up, especially if there are other electrical issues like the battery being drained constantly or the alternator not charging it properly.

I think it would be worth getting the battery tested and check that the alternator is putting out enough volts. Start with that ( as you can generally get them tested for free) and then work back from there.

Both these +++

There's no point just doing a visual. You need to get out the multimeter & check the resistance or volt drop between 2 points as the corrosion can be within a cable (esp an earth or main power feed cable). Also clean the connector to the electric power steer