Team-BHP - Intermittent electrical issues in my Grand i10

Hi fellas! Wishing you all a very Happy New Year! :)

We have a ’14 Grand i10 Sportz which happens to be driven by me these days. There is one issue which has been prevailing for couple of years now. I had upgraded to a Dual Trumpet Horn (Skoda type) and 55W Philips White Light bulbs (I can’t recall the exact name).

The problem that existed soon after the upgrade was that when I used to honk on Full Beam, the headlights used to stop working only till I pressed the horn.
Somehow, the car stopped doing that after a few weeks or maybe after a battery change, it became fine.

-Now, I’m using the car on a regular basis for over 2 months. Every morning when I go to my work, the Full Beam and Dipper DO NOT WORK and out of the two horns, only ONE HORN seems to be working.

-But when I return at 2 PM, the headlights and the horn seem to work JUST FINE. I really fail at understanding as to why this is happening!

I have gotten the Indicator Stalk changed, bulb holders cleaned, fuses and wiring checked, but nothing helped.
The OBD showed no error code.

Thank you in advance. :)
-AVIANSH.

Have you installed relays for the headlights? And relay for the horns?

In my view, the total current drawn by the headlight and horns is loading heavily and hence one of them is not working. If you have installed both relays with right input current ratings, this problem should not occur. The horn relay is drawing more current so as to cause the headlight relay to switch off and hence, bulb does NOT glow or goes off.

I am not sure about the logic with time. This may be just a coincidence or wrong interpretation of the fact.

Edit: I went through the problem description once again to realize that most probably, horn relay is culprit. Please check and replace with a good relay (the mechanics call it cut-out)

Quote:

Originally Posted by gkveda (Post 4974283)

Have you installed relays for the headlights? And relay for the horns?

Why would you need a relay if the OP has not really "upgraded" the bulbs in terms of wattage. As I can notice, the upgrade for the bulbs are only in terms of a better brand and keeping wattage and other specs same. There should be no reason for a need for a relay here which is ideally the case only when you upgrade to higher wattage bulbs.

I too feel the issue is the horn wiring and the absence of a relay. In general, if the OE horn is a dual tone pair, one need not install a relay as the OE wiring comes with one. However, if the car has come with a single horn, a relay is a must when you upgrade to a dual tone horn pair.

I also suggest to check the ground points for the Horn thoroughly because a weak ground is always and often the cause for such issues mentioned. Find a proper ground point on the body/chassis, scrape the paint fully and use a good quality ring terminal and bolt the ground cable for the horn and secure it properly.

Quote:

Originally Posted by dr.aviansh (Post 4974258)

But when I return at 2 PM, the headlights and the horn seem to work JUST FINE. I really fail at understanding as to why this is happening!

I have gotten the Indicator Stalk changed, bulb holders cleaned, fuses and wiring checked, but nothing helped. The OBD showed no error code.

You know, your problem reminded me of the GM Pontiac conundrum. It goes something like this :

Quote:

There is an interesting story that is related to the Pontiac, as reported by Daily Social.

One day, the Pontiac car division of General Motors received a complaint, saying, “My Pontiac car doesn’t like vanilla ice-cream.” General Motors, first ignored his complaint. The customer also knew, his complaint is silly. So the owner of the car decided to write again clearly.

He told them about how his family ate ice-cream every day after dinner. And each day, they would decide on a different flavour, but after he bought a new Pontiac car, he was facing a strange problem.

The car refused to start whenever he bought vanilla ice-cream. If it was any other flavor, there wasn’t a problem. While most people would have called him crazy, General Motors decided to send an engineer to his house anyway.

To the engineer’s surprise, the complaint turned out to be true. When the engineer got vanilla ice-cream, the car actually didn’t start. There was nothing left unchecked – the gas used, the car model, the time it took to drive back and forth.

Finally, the engineer realized, it took the man a lot longer to buy other flavors of ice-cream. But because vanilla was stored in a different case in the front of the store, it took little time. And this was just the clue he needed.

The answer was vapor lock!

Because of the car stopping and starting constantly, fuel would turn to vapor and couldn’t move through the system, and causing the engine to die.
Because vanilla ice-cream took little time to buy, the engine didn’t have time to cool down. And so the mystery was solved.

Sometimes the answers are lurking in places where you would least expect it.

The headlights have a relay. Your problem appears to be connected to the relay. When you head out in the morning, your batteries are not charged enough to activate the relay properly but on your return trip, the car's battery is probably charged enough. The relay needs 12 V or higher to operate effectively. Sometimes before they fail, they need more voltage to work. So substitute the relays and see if it changes the behavior.
But you still need to check your battery and alternator. Or something is using current in the night.

Quote:

Originally Posted by Prowler (Post 4975168)

Sorry for the noob question, issue related to relay is understandable but what you mentioned about the battery charge is something that I couldn't corelate. If the battery has enough juice to crank the vehicle, why can't it trigger the relay?

Quote:

Originally Posted by Mr.Boss (Post 4975211)

Cranking depends on the CCA rating of the battery while relay coil on/off depends on the terminal voltage. CCA is usually specified at 9V while Coils need at least 12V to operate. Probably @prowler can add to this observation.

Quote:

Originally Posted by Mr.Boss (Post 4975211)

As Srini Sir mentioned , the relays need 12.xx V to operate in a predictable manner. A fuel injected petrol engine may not require much effort to turn over. Relays OTH can crib about insufficient Voltage.
It is common to see horns fail to work when the battery is not fully charged during the night when the AC and headlights are on.