I have a Hyundai Accent X3 and want to change its instrument panel/dashboard light bulbs. It has 14V 1.4W bulbs (type 74 I guess), they are equal to T5 size but my T5 bulbs are 12V 1.2W (incandescent, not LED). Would it be any problem to replace with these?

Also there are T10 sized ones (type 194 or 168 I believe, 12V 3.4W), can I replace them to W5W, 12V 5W bulbs (incandescent, not LED) (datasheet is here) If it's 12V and 3.4W, new bulbs require 35% more amperage as I understand.

Would it be any problem with heat and amperage or anything else? Or should I use LED ones? Because they will be on instrument panel, I didn't want them to be so bright.

And also there are 3 bulbs with different type (ones with gray socket cap on photo), size is between T5 and T10, so I believe they are T3.25 (14V 3W marking on it). I could not find any replacement for them and can I replace them with T5s (incandescent, not LED) above using another T5 socket cap? Would that be any problem for electrical and heat means?

hyundai x3 instrument panel

Thank you very much for your help.


1 Answer 1


I'm not an electronics guy and I didn't sleep at a Holiday Inn Express last night (it's a joke ... no affiliation :o), but I do have some thoughts on what you're asking.

First, your vehicle runs on 12vdc. If the main bulbs you're talking about are 14vdc incandescent at 1.4w and running on that 12vdc power, they'll put out just a little bit less light than they would if they were being fed the entire 14vdc power they are rated at (I believe this is called being under driven, but not sure). Considering the new bulbs are 12vdc at 1.2w, I'll venture to assume the light output is going to be about the same as the original ones. IOW, I think these bulbs, as long as they are a direct fit, will give you no issues at all.

As far as the other bulbs you are talking about (T10), it sounds like they'll fit and work, but they'll be a little dimmer than the originals. Lower wattage = lower light output (at same voltage level). If you can put up with this and they fit, then they'll work.


I talked to a friend of mine who is an electrical engineer. Ohm's law applies here. He stated the 14v 1.4w light bulb is exactly the same as the 12v 1.2w bulb. Heat output should be exactly the same between the two of them.

With going from 3.4w to 5w, the amount of heat produced is negligible. We are talking such small amounts of energy, it most likely will not matter at all. If you are worried about it, light each bulb independently and see, by touch (gingerly) how much heat is produced by either one. Alternately, you could also use a no touch thermometer if you have one to get the exact temps.


Have you considered ordering the specific bulbs you need from Hyundai? They'll have direct replacement and you won't have to worry about heating at all.

  • Thank you for your answer, actually my main concern is about the heat and higher current. Lower light output is not a problem but higher current due to lowered voltage and heat may lead to fire and I wouldn't want that :)) Mar 1 at 8:58
  • Thank you very much for your edit and answers. unfortunately these bulbs are so old (from 90s) and Hyundai doesn't provide any direct replacement. Mar 1 at 22:36
  • And another weird thing is, while most cars operating with 13-14 volts, Osram's T5 and T10 bulbs are tested with 13.5V, so that's another concern for me to use 12V bulbs with 13-14V constantly. Mar 1 at 22:38
  • @shehatesme - EVERY "12v" car runs at 13-14v ... there are no issues there. Mar 1 at 23:00

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