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Hello. I have a 2017 Elantra and my rear defroster is not working. When I press the button to turn it on, the light in the button does not turn on. I am assuming it is a blown fuse. The problem is, when I review the fuse information in the manual, there is not a fuse that is clearly marked to control the rear defroster. Can someone point me in the right direction? I would love to be able to figure this out without having to take it to the shop.

Thank you
 

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Try pulling the heated mirror fuse and seeing if it is blown. The switch controls the rear defroster and heated mirrors so only makes sense the fuse would be the same one.
 

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Two different rear defogger systems for the Elantra, mine has the auto system, switched on with the window defogger, assume since yours has a manual switch, will be the circuit marked just defogger.

Lets hope it not a blown fuse, something is shorted out, these can be a problem to find. Could be a loose fuse in the fuse box, that 7.5 amp fuse is identified, by looking at the rear of the fuse covers, either the dash or under the hood.

Hope these circuits help, can see, they are not just a simple switch with all this computer stuff.
 

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On the other hand if the defrost switch is defective in the HVAC control panel, may want to take it to your dealer. Can't replace just the switch, whole panel needs to be replaced for around 500 bucks.

Been this way for a long time, most common switch to fail was for the blower motor, most only held in by two screws, could not just buy a new switch, had to purchased the entire panel. Guess they figured mechanics were not smart enough to remove two screws.
 

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Been this way for a long time, most common switch to fail was for the blower motor, most only held in by two screws, could not just buy a new switch, had to purchased the entire panel. Guess they figured mechanics were not smart enough to remove two screws.
This makes it sound like you assume they are :wink::laughing:
 

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This makes it sound like you assume they are :wink::laughing:
Had no reason to remove the climate control panel, but if its like that gear shift panel with five switches on it, had reason to remove this.

That little door to lift to get access to manually knock the gear shift lever out of park. was next to impossible to open. With this panel removed, could release it from the bottom, has a square edge on it, filed that to a bevel so it could be lifted from the top.

While looking at those five switches, no screws, were all glued in place, those would not be easy to replace.
 

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Discussion Starter #7
Thanks folks for the input. I did take the car into the dealer. Sure enough... not a fuse, it’s the switch. And - also like you said - they must need to replace the whole panel because they want $500 to fix it. Is there any way this could be a DYI job?
 

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Thanks folks for the input. I did take the car into the dealer. Sure enough... not a fuse, it’s the switch. And - also like you said - they must need to replace the whole panel because they want $500 to fix it. Is there any way this could be a DYI job?
What is your level of electronic repair skills?
And what kind of tools do you have to do this kind of repair?

Use to be, all you needed was a screw driver and a soldering iron.

Note: If you try to repair it and fail
Then will it cost anymore to fix it?
 

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Discussion Starter #10
;5664442 said:
On the other hand if the defrost switch is defective in the HVAC control panel, may want to take it to your dealer. Can't replace just the switch, whole panel needs to be replaced for around 500 bucks.

Been this way for a long time, most common switch to fail was for the blower motor, most only held in by two screws, could not just buy a new switch, had to purchased the entire panel. Guess they figured mechanics were not smart enough to remove two screws.
NicholasD - I purchased a new panel to replace what I Hope now is just a defective switch. Any suggestions you can share in the replacement? I found a video on YouTube for replacing the radio and they started by taking off a dashboard length trim panel (accessed by a screw on the passenger-side of the dash) to access the screws needed to hold the radio. Do I need to start there to access the 2 screens you referenced in your post? Thanks.
 

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There is a work around for a nonfactory switch. You will have to get another switch, preferably one that lights up. There's a black wire on front of cabin fuse box in the black plug (plug I/P-D, pin 7). This is the ground signal to the defrost relay.

You can tap into this wire with a switch and ground on other side of switch. The only problem is that you will have to remember to manually turn switch off and on since it bypasses the computer.

Looks like you already got factory switch, but info maybe useful to someone else.
 

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Rear window defrosters pull 25 amperes, and more than just a switch, a 15 minute timer.


These came out in the early 60's, just carried a snow brush on one side of a stick and an ice scrapper on the other end and never used them.


During that phony energy crisis people were going nuts buying sub compacts dealers were adding a stupid aftermarket rear window defroster with wires taped to the headliner so they could charge an extra thousand bucks. Just stuck with my well tuned 70 Riviera that got 22 mpg, these cheap pieces of crap were lucky to get 18!


Do have concerns about our 2017 Limited MVAC system, outside of the AC, should be covered by that six year warranty. Hyundai went nuts and copied Ford's evaporator box, stupid, any problems with that box. AC system has to be recovered that darn near had to be completely replaced using Al Gores stupid PAG women's makeup oil, what an AH and all lies.


Getting old and tired, if still around, will pitch the car and buy a new one.
 

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Try pulling the heated mirror fuse and seeing if it is blown. The switch controls the rear defroster and heated mirrors so only makes sense the fuse would be the same one.
Yes! Replacing the "heated mirror" fuse solved the problem with the rear defroster light button not working. Thanks!!!
 

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Would be a lot more concerned as to why that fuse blew in the first place, the defogger fuse is a 50 ampere fuse, and the defogger only draws half that of 25 amperes.

Lots of precautions on cleaning the inside of the rear window or putting objects back there that can scratch it.

In electronics, last thing you want to find is a blown fuse, long ride between defogger switch and the rear window defogger, could be an intermittent short to ground someplace.
 

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The owner's manual also provides more information about what each fuse covers. Some of the fuse names on the panel don't tell you much (e.g., "MODULE 1" or "MODULE 7" ), and some just give you some of the info (Like "HEATED MIRROR.") Though in this case, the rear defroster is not explicitly called out, looking at the fuse listing in the owner's manual shows that the "Heated Mirror" is one of two fuses that are for the A/C Control module, which contains that switch.
 

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The owner's manual also provides more information about what each fuse covers. Some of the fuse names on the panel don't tell you much (e.g., "MODULE 1" or "MODULE 7" ), and some just give you some of the info (Like "HEATED MIRROR.") Though in this case, the rear defroster is not explicitly called out, looking at the fuse listing in the owner's manual shows that the "Heated Mirror" is one of two fuses that are for the A/C Control module, which contains that switch.
Maybe Hyundai should hire an English Speaking engineer. I see my circuit diagram was reduced, can barely read the fuse information. Ha, like to keep us guessing.
 

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Rear window defrosters pull 25 amperes, and more than just a switch, a 15 minute timer.


These came out in the early 60's, just carried a snow brush on one side of a stick and an ice scrapper on the other end and never used them.


During that phony energy crisis people were going nuts buying sub compacts dealers were adding a stupid aftermarket rear window defroster with wires taped to the headliner so they could charge an extra thousand bucks. Just stuck with my well tuned 70 Riviera that got 22 mpg, these cheap pieces of crap were lucky to get 18!


Do have concerns about our 2017 Limited MVAC system, outside of the AC, should be covered by that six year warranty. Hyundai went nuts and copied Ford's evaporator box, stupid, any problems with that box. AC system has to be recovered that darn near had to be completely replaced using Al Gores stupid PAG women's makeup oil, what an AH and all lies.


Getting old and tired, if still around, will pitch the car and buy a new one.
25 amps and It takes 109 years for the window to clear up.
 

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Electrical engine cooling fans can also put on an additional 25-40 ampere load on the alternator, but rare to run these fan or fans at the same time as the rear window defroster, Elantra calls this a defogger.

The conflict here is the alternator needs the greatest output when engine heat loads are the greatest when driving in slow city traffic, but should have no reason to switch on the "defogger".

This was really a challenge when the industry switched to FWD eliminating the engine driven fan. And marketing demanded a high output alternator a idle speeds.

The next crazy thing was the single drive belt, ha, stupid salesman say you only have one belt to replace, but with the AC on, driving in hot weather with very little air flow through the condenser generating a lot of extra heat, that alternator and compressor is putting a heck of a load on that belt. Removing the hydraulic power steering pump did not help much, electric power steering also can add up to 80 amp surgers for that alternator.

What that same signal belt also drives is the water pump, low melting aluminum engine, if that belt breaks so will your engine.

Engineers think about stuff like this, so when forced to drive in slow city traffic, switch off the AC and roll down the windows to save on all this stress. Practically all vehicles are using single belt drives. Even worse is that the alternator, water pump, and AC compressor use what I call limited lubricated ball bearing, hardly a finger tip full of grease in there and grease does dry up. Even worse is when some manufacturers started buying bearings form China. No made with USA grade A steel, but from junk you tossed in the trashcan where it should have stayed.

Well retired now, no more battles with marketing or bean counters. At 50K miles been pulling the bearings out, replacing with difficult to find USA, Canada, Japan, or even Polish bearings, but never made in China.

This should be covered under the ten year PT warranty, one darn good reason to purchased a Hyundai after doing a lot of looking. Most new vehicles are only carrying up to a five year warranty or 50K. So if you drive over 10K miles a year and finance these things for five years, not only huge monthly payments, but the troubles are yours.
 

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25 amps and It takes 109 years for the window to clear up.
I haven't noticed that it takes too long for the window to clear up. I do find that on a trip, if there's a need for the defogger, it is needed not just for a few minutes on startup, but for most of the trip. I wish there was an override to make it stay on. A minor inconvenience.
 
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