Question regarding the Windsheld defrost

[DKAwildcat]

I ordered 24 plugs today to diffuse the air.

Just curious... Several people in another thread stated their windshields cracked when the defroster was turned on. The air coming out the center of my diffuser gets pretty hot (to the point where I have to remove my hand). I would think that the high concentration of heat at the center of the windshield (with the sides being much colder) would cause the center glass to expand more than that on the sides; thus, causing excessive stresses that lead these windshields to crack. Thoughts?

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[18BlackJLRU]

Be careful, these holes are bigger... I almost lost two plugs in them, they have been a pain to remove.

 

[Rhinebeck01]

@18BlackJLRU

Good you mentioned this... also, with any of the other vent holes, if you push to hard on the plastic plugs when you are installing them, you can push the plug right though to never seen again land. I almost sent one that way.

 

[BigJimSlade]

I got the tinkering bug this afternoon so I decided to see what I could come up with to address this issue. My first attempt is 3/4" 12 gauge flat bar zinc with a notch cut out of the middle. In its current configuration I get a good jet of air in the middle of the windshield and a lot of flow on both sides. Once I determine that it's good to go I'll hit it with some satin black and attach it either with zip ties or wire, which will be basically impossible to see.

*Edit* I should mention, the 4 foot bar was $4.71+tax at Home Depot.

 

[Rhinebeck01]

@BigJimSlade

Can tell you that zinc is gonna get hot hot hot. Even the plastic plugs I am using, get so hot, you can hardly touch them.

To bad you could not do that with some plastic stock.

 

[BigJimSlade]

@BigJimSlade

Can tell you that zinc is gonna get hot hot hot. Even the plastic plugs I am using, get so hot, you can hardly touch them.

To bad you could not do that with some plastic stock.

That's why I went with metal. I'm afraid some plastics would melt. I ran it at full blast for several minutes and hit it with a laser thermometer. The metal was running between 114-118 while the vents to the left and right of it were 128. So, I think I'm good there. But, I need to test it again in the summer sun. If it's a problem I'll just use it in the winter.

 

[DKAwildcat]

That's why I went with metal. I'm afraid some plastics would melt. I ran it at full blast for several minutes and hit it with a laser thermometer. The metal was running between 114-118 while the vents to the left and right of it were 128. So, I think I'm good there. But, I need to test it again in the summer sun. If it's a problem I'll just use it in the winter.

Thanks for measuring the temperature coming out of the vent! The square plastic plugs are made from polyethylene. For my own comfort of mind, I looked up its melting point and here is what I found: “For common commercial grades of medium- and high-density polyethylene the melting point is typically in the range 120 to 180 °C (248 to 356 °F). The melting point for average, commercial, low-density polyethylene is typically 105 to 115 °C (221 to 239 °F).” Therefore, these shouldn’t melt.

 

[Yeeper]

My first post! I’ve been browsing the forum for months now, collecting all the info I can before I order in March (when my current lease is up) and this is by far one of the best fixes I’ve seen! Thanks for the info!

Can’t wait to order mine!

 

[Capt-Zoom]

Best fix would be new vents from FCA as part of a recall.

 

[DKAwildcat]

For now I’ve installed all 24 caps as can be seen in the photo. Although the center 12 vent openings are plugged, there’s still enough air getting through to defog that part of the windshield.

 

[Rhinebeck01]

@DKAwildcat

Since you only have the 24 plugs, I would start at center and do 12 plugs on each side of center. Leave no open holes. You will find plenty enough air sneaks through so the the center will stay defrosted even though you have all holes plugged.

I have been testing with 16 plugs on each side of center, with no open holes in the center, and I have obtained very good results.

Guess the point of my post is to let you/guys know you, do not need to leave open / unplugged holes in the center.

 

[TRZ]

I had this same issue when I first started using the defroster with the cooler weather. The air would only come out of the center defroster vent as the OP shows. I had a sneaking suspicion that this was not supposed to happen as the driver side was fogging over badly. I took it to the dealer immediately. They quickly fixed it by removing the dash and removing what they called "factory debris" from the driver side vent. They had several JL owners come in for the same issue. They popped the dash back on and I tested the vents, it all worked beautifully from there. Now I've got good air flow coming out of all the defroster vents.

Aaron, which Denver dealer did you go to for this?

 

[paffemt]

I have 2 Pro Clips mounts installed on my dash and they seem to divert the air nicely. Didn't have any problems with the snow and ice yesterday melting on the outer edges of the windshield

 

[MacombRoger]

I found this thread by a search...Glad its not just me. Read through all 17 pages. And promptly ordered 2 packs of 10 from Ebay (ordered before I saw he offered a 24 pack). If $20 solves this problem I will be happy. Sure Jeep should issue a TSB and offer a more factory fix, but I need something now. Past Monday when Detroit got all the snow, the Edges of the windshield would just not release the snow and ice. I couldn't figure out why it didn't get warm enough to just at least fall off at speed. The wipers do seem to ice up a lot too. But I don't know if that is related to the vent issue, or cheaper factory wiper blades.

Any way thank you everyone for identifying the problem and working a way to an acceptable and affordable fix.

 

[DKAwildcat]

@DKAwildcat

Since you only have the 24 plugs, I would start at center and do 12 plugs on each side of center. Leave no open holes. You will find plenty enough air sneaks through so the the center will stay defrosted even though you have all holes plugged.

I have been testing with 16 plugs on each side of center, with no open holes in the center, and I have obtained very good results.

Guess the point of my post is to let you/guys know you, do not need to leave open / unplugged holes in the center.

Reinbeck01: I did as you said and it definitely provides a much better distribution of air across the windshield. I may order another package in order to force more air to the sides.

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