05/09/2026
It's been a busy but rewarding week this week at Motolec.
We've had a run of Korean cars in this week, which is unusual
Two were for battery drains, which again is unusual.
The first one was a Hyundai i10 with a 300mA drain.
The customer didn't report any obvious faults or recent work when asked, but we spotted something straight away.
The "lights on" symbol was lit on the instruments.
But the lights weren't on.
They switched on and off properly.
We had 2.7V at the "lights on" input to the instrument cluster.
The circuit connected to 14 items.
Luckily there was a splice pack which allowed things to be split down easily.
Investigation led us towards the hazard switch.
We tried it, it didn't work.
Had there been liquid spillage?
But then we noticed a scuff on the dash.
We rang the customer to ask again if anybody had taken that panel off.
Ah yes, I had my heater control repaired in June.
Ok. So now we had good reason to remove the panel again.
As soon as the panel was removed, the issue was obvious.
The plugs for the hazard switch and passenger airbag indicator had been transposed.
We told the customer what had been found and commented that we were surprised they didn't have an airbag light on.
"Oh yeah, it WAS on"
**PLEASE don't withhold information.
Just like forensic detective work, the more evidence and clues we have, the less time the investigation takes and therefore the less it costs.**
The second Korean car was a Kia Rio.
This had a massive 1.46 Amp battery drain.
That's EXTREMELY UNUSUAL.
Surely something must be getting pretty warm taking that much current.
The thermal camera revealed nothing in the cabin or boot.
The engine bay was still pretty warm, so that muddied the waters a bit.
Voltage drop testing was carried out on the fuses in the cabin and engine bay.
One fuse had a significant 4.3mV drop.
Service info revealed that related to high beam.
But the high beam relay was cold.
The lights weren't on.
Digging deeper into the diagrams showed this car had single lamps, with a shutter to change the beam pattern.
We pulled the fuse and heard a clunk from each headlamp.
The current drain was now 2mA.
But how were the shutters being powered if the relay wasn't energised?
Again, we found some witness marks on the relay case.
Removing the relay, we found a hole in the casing.
Someone had levered the relay, broken the casing and bent the contacts inside so they were always made.
The customer later informed us he had changed the headlight bulbs in an attempt to get the high beam working, but the reality was the headlights were on high beam whenever they were on because of that damaged relay.
The third had been diagnosed last week, it had a faulty door latch which was stuck deadlocked, and faulty passenger window switch.
Last week after repeated attempts, we managed to release the deadlock, then temporarily disconnected the deadlock motor so the door could be locked and opened and made this week's job easier.
The deadlock wire was reconnected once the new latch was fitted.
The final Hyundai, an ix20, had multiple faults.
We started with the airbag light, faults were set for both front impact sensors.
Diagrams led us to a connector in the passenger footwell, we found every single wire was chewed through, a 5 inch section of wiring harness was missing!
We reinstated that, which also addressed the concern of the washer pump not working.
We then found that another connector had multiple broken and bare wires.
All except 3 of them needed new sections spliced in.
Another couple of hours later, final tests revealed the weird radio fault was still present.
We found further damage at the passenger door connector, where one of the speaker wires was shorted to a central locking wire.
Four wires were repaired there and that finally checked off every item on the shopping list.
