[Amc2022]

When driving a short distance the ESP off light comes in, the car dies then when started again, drives but still with ESP off light on &  rev counter stops working.. car also feels sluggish when driving. Car garage says no faults coming up on computer so can't help.... HELP!!

[Basshead]

I’ve got a 2010 i30cw where the “ESP off” light has illuminated on the dash at random intervals over the past couple of weeks. When illuminated, it also disables the cruise control.  There are a couple of older threads with similar symptoms which I can’t reply to.

From research so far, it seems to be related to a faulty brake pedal switch but what I was confused about was the top high-mount brake light still works, but the side brake lights don’t work (despite the globes testing ok). I expected if the brake pedal switch was faulty then all brake lights wouldn’t work.

I have a obd2 reader and scanned for codes and it found P0703 “brake switch ’b’ circuit”confirming faulty switch.

I’ve also checked some older recalls and my VIN# seems to be outside of the recall range. Not sure if Hyundai are going to honour this or if I’ll be paying for the replacement switch and labour….

[Aye30]

The brake light switch has two separate circuits in one unit. It can operate the high mount brake light , and the lower pair of lights separately. And if both circuits dont register in the BCM or another computer somewhere, it will set the "esp off" light. A multimeter under the dash set to continuity , for both sides of the switch would have saved me from buying the switch, (I had two blown globes)

[Basshead]

Thanks for your reply. I only checked one globe, so I will check the other globes before ordering the switch/relay

Rich.

[Aye30]

I believe if one globe is blown the other side should still light up. Wired in parallel.  I was just unlucky as both had blown, and I assumed it was the switch, as I had only recently  replaced one with a narva brand.  If they blow again soon I may have to examine all the ground straps and check the alternator.

[Basshead]

I checked all 4 globes (2 per cluster) are working this afternoon, so it looks like it’s going to be the switch replacement for me

[Basshead]

After getting a hold of my local Hyundai service dept (they didn’t return my call from yesterday), I was told they still need to charge $180 to scan for codes even though I just told them I had already done that and the code number. They wouldn’t budge on the code scanner fee (claiming theirs was better). They just reinforced my hatred for dealerships. At least they agreed to check the VIN number to see if it was covered by a recall (but I didn’t have it on me at the time).

I’ll try another dealer (but hoping I can just buy the part and replace it myself - if I can find out where the switch/relay is located - my guess is it’s behind the brake pedal)…

[Aye30]

A message for Basshead. You checked the bulbs? The brake bulbs in the hatchback is a bay15d, It is a bit special, in that it has offset pins and two contacts at the base. Does the wagon have and or need the same bulb type? If it does then the brighter of the two filaments in the bulb is the one that is needed for the signal to get through. A broken bulb may still light up on the other filament, but still be unlit when the brake is pressed.

[Basshead]

I visually checked and used ohmmeter to test continuity of both elements in all 4 globes and they were all ok.

[Basshead]

I’ve called another Hyundai dealer and they want >$200 to do a scan.  I looked under the dash and found this switch behind the brake pedal.

Brake light switch for Hyundai FD i30 1.6L 2.0L 4 pin 10/7-4/12 2 Yr Wty | eBay

Worth a try to see if it fixes the problem.

[Basshead]

I’ve tested the switch and both circuits don’t work (one set of contacts should be normally-open and other set of contacts should be normally-closed). I ordered a replacement switch from eBay which works (tested with ohmmeter) but replacing the switch didn’t fix the brake lights issue. I checked the stop light fuse (driver’s side end of dash where door closes) and it is ok (and top brake light still works).

I wonder if it’s related to the auto trans…  googling indicates the torque converter gets a signal from the brake cct to know to disengage 1:1 ratio when brake pedal is pressed. Maybe there’s an issue with the auto trans (I know the stall-converter/valve isn’t in a good condition; see my other post regarding rough gear changes especially when coming to a stop).

[Basshead]

Ok so I’m an idiot… the globes I tested were just the parking globes. As none of the lower brake lights were working (and I didn’t check which ones were the indicators), I assumed the parking globes were dual-element. The very bottom globes are the brake lights and it turned out they were both blown. The switch was faulty as well anyway, which I had already replaced. Now just waiting to see if the “ESP off” light on the dash returns…