Hyundai Elantra heating/air turning on and off

My car has been having issues lately, I’ll have the heat or air on (doesn’t matter which), and I’ll hear a click (like a pen click) and it will go off, then it will click again and go back on. Last year it only did this a couple of times and I solved the problem by hitting the dashboard, obviously. But now it’s doing it every time I drive, and since it’s winter I kind of need the heat to stay on. What is the problem?

I have to assume that what is turning on and off is actually the blower fan? So you hear a click and the fan stops blowing air out? Or are you saying that the fan keeps blowing air but it stops blowing warm/cold (whichever) air?

Assuming that the fan just stops blowing but the actual temp of the air doesn’t change then you have an issue with the blower motor circuit. It starts at the switch on the dash, goes to a resistor, and then to the fan. Somewhere the circuit will involve a fuse and maybe a relay. Hyundai’s design might also involve other things I don’t know about.

So someone has to check out your blower motor circuit. You can at least stick your head up under the glove box and find the main power connector for the blower and inspect it. Pull it off, clean it with some electronics cleaner, look for obvious damage and make sure it connects tightly. But your issue may be elsewhere.

The air or heat stops all together(blowing and temperature) after the click then i hear another click and it goes right back on.

Depending on the year of the Elantra, the main fuse panel (for a 2004-2006) is behind the small drawer above your left knee.

The main relays (and some fuses) are under the hood driver’s side.

My Elantra’s A/C (which is also the defrost) has also started acting up, much the same as your description.

It started after I swapped out relays in the main relay panel while troubleshooting a headlight problem.

The relays for the most part are interchangeable - ensure the stamped part numbers are the same, and the relays are relatively cheap, somewhere between $11-$15.

The underside of the relay panel describes which relays relate to specific circuits.

I am 85% sure my A/C and defroster problem is being caused by a weak relay that was causing my headlights to blow out after using my light switch to turn off my headlights when approaching a guard gate in early morning hours.

Just remember, if you do swap one relay for another and it fixes your problem, you will end up with a new problem in another circuit. Meaning, if swapping the relay works, go out and buy a new replacement and actually replace the troublesome relay.

Good luck!