Brake lights cutting power to ICE???

tmanish76 · 28th March 2008, 09:32

Guys, am facing a strange problem. Since the last two days whenever I use the high beam in the morning or hit the brakes, my ICE powers off and on again.

This happens only in the mornings and not at night when I drive with the lights on. Also, the symptoms surface only after I drive some distance on the highway. In normal stop and go traffic, things are fine. If I try the high beam while stationary the rpm indicator does a small jump while the ICE goes off and if I do it while the car is running, there is a slight jerk in motion.

Doubt that the battery is the problem as the lights, horn and other electricals work fine. Could someone please throw some light on this issue?

clevermax · 28th March 2008, 11:09

Check your battery, and the dynamo.
All cells in the battery, The charging voltage etc. Seems like the battery is not getting properly charged.

And if you have to change the battery, take good care of the new one, do not allow any local mechanic to top-up the battery with water every now and then. This is a bad practice and it surely reduces the life of the battery. The battery in my car was working fine for 6 years, until a mechanic opened it up for top-up. Within 2 weeks, one of its cells died.

tmanish76 · 28th March 2008, 14:00

Thanks Max...but I had the batter checked recently and it was fine. Additionally, the car runs ICE and headlights without the engine on quite well. Would this not indicate that the battery was fully juiced?

Quote:

Originally Posted by clevermax

Check your battery, and the dynamo.
All cells in the battery, The charging voltage etc. Seems like the battery is not getting properly charged.

And if you have to change the battery, take good care of the new one, do not allow any local mechanic to top-up the battery with water every now and then. This is a bad practice and it surely reduces the life of the battery. The battery in my car was working fine for 6 years, until a mechanic opened it up for top-up. Within 2 weeks, one of its cells died.

harsha.cs1 · 28th March 2008, 14:58

hi manish,
i think you might have to check the battery and the alternator. the battery is not getting charged properly due to some reason. how old is your battery?
- Harsha

tmanish76 · 28th March 2008, 17:25

Hey Harsha....how's you man.....?

The battery is about 2 years old. But if the battery was the problem how is it functioning all right at night is what is puzzling me.

Quote:

Originally Posted by harsha.cs1

hi manish,
i think you might have to check the battery and the alternator. the battery is not getting charged properly due to some reason. how old is your battery?
- Harsha

clevermax · 28th March 2008, 19:33

Now I'm getting it.. It might probably be a relay problem, and because of which, the Head unit is not getting power for a split second or so. So it turns off and turns on again. the relays of the high beam or the break lights might be momentarily hindering the power supply to your head unit.

From your description, the battery and the alternator seem to be okay...

tmanish76 · 31st March 2008, 10:30

Finally...we seem to be getting somewhere. Now, would you have any idea where this relay is located. Am scared to give the car for repairs to Hyundai lest they give some other analysis and fleece me for a simple relay problem.

And just for the record, drove the car today morning after leaving it parked over the weekend and there was no problem even on the highway.

I feel that when I speed up something is getting overcharged and tripping the relay you mentioned.

Quote:

Originally Posted by clevermax

Now I'm getting it.. It might probably be a relay problem, and because of which, the Head unit is not getting power for a split second or so. So it turns off and turns on again. the relays of the high beam or the break lights might be momentarily hindering the power supply to your head unit.

From your description, the battery and the alternator seem to be okay...

harsha.cs1 · 31st March 2008, 11:28

Quote:

Originally Posted by tmanish76

Hey Harsha....how's you man.....?

The battery is about 2 years old. But if the battery was the problem how is it functioning all right at night is what is puzzling me.

Hi Manish,
I am fine, thanks. Your problem is unique, as are most auto electrical problems! Do check out my defogger issue! http://www.team-bhp.com/forum/newrep...reply&p=775442

Anyway, i too guess your problem might have something to do with the relay. Not sure where it lies, but i guess it would either be in the fuse box under the hood or the one in the passenger cabin just to the right of the accelerator. I once had a burnt relay and it did give a burnt smell in the passenger cabin. so i guess this would be in the fuse box near the driver's right foot. Yes, it is important to go to some good auto electrician. Many big garages don't know their auto electricals well. As regards A.S.S., i have been told that they fleece because they prefer to replace than repair. If some wiring has gone wrong, they just order replacement of the whole loom!
Do keep us posted!

28th March 2008, 09:32	#1
tmanish76 BHPian Join Date: Aug 2007 Location: Mumbai Posts: 50 Thanked: 0 Times	Brake lights cutting power to ICE??? Guys, am facing a strange problem. Since the last two days whenever I use the high beam in the morning or hit the brakes, my ICE powers off and on again. This happens only in the mornings and not at night when I drive with the lights on. Also, the symptoms surface only after I drive some distance on the highway. In normal stop and go traffic, things are fine. If I try the high beam while stationary the rpm indicator does a small jump while the ICE goes off and if I do it while the car is running, there is a slight jerk in motion. Doubt that the battery is the problem as the lights, horn and other electricals work fine. Could someone please throw some light on this issue?
	() Thanks

28th March 2008, 11:09	#2
clevermax Senior - BHPian Join Date: Jun 2006 Location: Tvm/Amsterdam Posts: 2,086 Thanked: 2,640 Times View My Garage	Check your battery, and the dynamo. All cells in the battery, The charging voltage etc. Seems like the battery is not getting properly charged. And if you have to change the battery, take good care of the new one, do not allow any local mechanic to top-up the battery with water every now and then. This is a bad practice and it surely reduces the life of the battery. The battery in my car was working fine for 6 years, until a mechanic opened it up for top-up. Within 2 weeks, one of its cells died.
	() Thanks

28th March 2008, 14:58	#4
harsha.cs1 BHPian Join Date: Feb 2008 Location: Bangalore Posts: 224 Thanked: 2 Times	hi manish, i think you might have to check the battery and the alternator. the battery is not getting charged properly due to some reason. how old is your battery? - Harsha
	() Thanks

28th March 2008, 19:33	#6
clevermax Senior - BHPian Join Date: Jun 2006 Location: Tvm/Amsterdam Posts: 2,086 Thanked: 2,640 Times View My Garage	Now I'm getting it.. It might probably be a relay problem, and because of which, the Head unit is not getting power for a split second or so. So it turns off and turns on again. the relays of the high beam or the break lights might be momentarily hindering the power supply to your head unit. From your description, the battery and the alternator seem to be okay...
	() Thanks