[vishnuvijay]

yesterday i noticed that my ohc's headlights dim slightly when power windows are operated.

is it normal or
is it the alternator or
is it the battery or
is it something else?

i don't have this problem while playing music.

[suman]

How old is your battery? Do the lights dim slightly when you press the horn button?

[Sprucegoose]

I have a '98 OHC, my headlights don't dim when i roll up the power windows.
the lights do dimm when i blast music though, dims in sync with the beats. [that means i need a capacitor right?]

I think it would be the alternator

[kannan666]

Originally Posted by suman

How old is your battery? Do the lights dim slightly when you press the horn button?

In addition, do they dim when you are only operating them off the battery or do they dim when you operate them even when the car is running and the battery is getting charged ?

[esteem_lover]

The PW motor draws quite a bit of current. Like Suman said it could be the battery if it is old. Or check the HL relay & change it if you must.

[deepaktpatil]

Originally Posted by suman

How old is your battery? Do the lights dim slightly when you press the horn button?

This is the first question that came to my mind too. It could one sign of battery on its last legs.

I had a similar problem with my Accent but I knew it was because of my OEM battery which was serving me for 6 years. Problem went away after I replaced my battery.

[Psycho]

Get the window channels cleaned properly, drops the load on the window motors drastically.

[anupamsinha]

The same thing happens in our Palio. The battery is around 3 yeards old and make is Amaron.

[esteem_lover]

My idling drops when I operate the PWs.

[akshay4587]

Originally Posted by esteem_lover

My idling drops when I operate the PWs.

same here but only when i operate 2 windows simultaneously.
my battery is 4.5yrs old and is weak now.
may be thats the reason

[aaggoswami]

There is a thread on this IIRC where even I had posted similar thing for Baleno. But this was when the car was idling.
If all this happens during idling, then there is no issue with your car. What I have understood here is this.

As we know, powerwindow motor or brake light and headlights take a good amount energy. When the car is idling, it just produces enough torque that is necessary. Next, when you use powerwindows or such equipment, then more amount of energy is drawn, so the engine adjusts air and fuel such that it produces just enough amount of torque that keeps the equipment ON and runs the engine. Here the idling will rise a bit and after the fuel and air ratio is adjusted the idling will again drop a bit.

I will search for the original thread.

EDIT :
The thread is here : http://www.team-bhp.com/forum/techni...eadlights.html

Read the post here :
http://www.team-bhp.com/forum/1370261-post8.html

hey there is no ac ideling control,or ecu sensing that more current is being drawn by headlights,its just that,both AC generator as well as ac comperssor are in direct couple with engine,when they are switched on,engine is loaded,sensing engine load more fuel is injected to copeup,hence rpm rise,however ecu constantly updates itself and keeps trying to reduce rmp upto the idle threshhold because of no throttle input,in some cases(cars) the engine produces enough torque at idle with just a slightly richer mixture,in this senerio the rpm falls back with slightly richer mixture,others the rpm rises slightly to produce just enough torque to keep revving.

even in crab modles below certain rpm,the solonoid valve in the crab operates to uncover another jet to add fuel,so when ac is switched on,rpm tends to fall,taking it below the set limit and hence additional fuel goes in,so rpm rise again! however in crab models ,it usually means that crab butterfly is not in good state and is leaking air into engine even with no throttle,because solonoid is suppose to be open at idle anyway!.but when buterfly is already leaking air,or crab is in bad state of tune,enough charge is already fed to engine not requiring the solonoid valve to operate(consumes more fuel in this condition)
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[ghpk]

Its due to Weak Battery, as in most cases.

if you also experience a little delay in cranking
then its for sure your battery is getting retired soon.

[vishnuvijay]

the battery is 3 years old and it's exide.

i noticed dimming when i switch on the ac too. i checked with engine on. i'll get my battery checked although there is no delay in cranking.

esteem_lover, i had upgraded the headlight bulbs to philips rally 100/90 with relay. i'll get them checked too.

psycho, i'll get the window channels cleaned properly, car's service is due now.

[.anshuman]

Ive seen this phenomenon happen in a lot of cars, this happens when the glass is fully up and still the motor tries pushing.

Does it happen with auto-up feature?

[esteem_lover]

Originally Posted by akshay4587

same here but only when i operate 2 windows simultaneously.
my battery is 4.5yrs old and is weak now.
may be thats the reason

Noticed yesterday that the idling drops when I switch on the blower too. Weak battery I guess, mine is 4 plus years as well.