Hello everyone, happy new year and all that good holiday stuff. Anyway i'm new to the forums here so believe me, i'm trying my best to navigate and post in the correct areas! ( i also looked for similar issues and didn't find any)

Anyway I recently as of a month ago purchased a 03 g35 coupe 6mt, am in love with the car and am in the stage of correcting all of the previous owners issues, "Clunking control arms, Door lock actuator, Window regulator etc etc" I finally resolved all of the issues and then the Canadian weather decides to come in and dump rain, snow and ice all over the roads.

On my way home from work a big puddle was situated in the middle of the road and with no way of avoiding it I drove through, belts squealing for a second only seemed to be the immediate repercussion. A couple hours pass and I drive the car again with all of my defrosters on. While driving the horn all of the sudden starts blaring, not knowing why i decide to pull over and shut the car off. Turned it back on nothing, turn my front windshield defroster on and still nothing, Turn the rear defrost on and the horn once again starts blaring. If i honk the horn on the wheel the rear defrost light also turns on. (like their somehow connected)

oh and also after the rain finished it dropped below freezing so now there is a sheet of ice on my car, do you think parking it in the garage and letting it dry out for a night could resolve it?

Does anyone have any sort of idea whats going on here or what I need to do to fix this issue, any help would be appreciated, Thanks

 

You got something wet that shouldn't be. I'd park it a garage, open the hood, take out the battery and make sure the fuse box in there is completely dry. Hopefully it'll dry out and be OK.

 

Did exactly this, removed battery and let it dry out, noticed some water by the fuse box so I grabbed an air gun and blew everything out, then my horn started making weird chirping noises then stopped. Put everything back together and hit the lock button on the fob, beeeeeeeeep the horn was stuck, popped the hood removed the fuse, put it back in, turned off the key fob horn beep by holding lock unlock simultaneously locked the car and everything was fine.

While driving decided to hit the rear defrost button and the horn this time was stuck with no way of turning it off, so i pulled over got the fuse out and left it out, tried the defrost button now and it seemed to work.
But now when i turn on the rear defrost it turns on my rad fans, doesn't matter if the cars hot or cold, if the rear defrost is on the radiator fans are buzzing away.

This is absolutely blowing my mind I have no idea whats going on here.

 

Can you tell me specifically what fuse you pulled? The fuse # and Amp rating, it would help with troubleshooting. I see a fuse for the horn in the wiring diagram #35 (15A) is this the one you pulled?

 

After reviewing wiring diagrams in the Service Manual, Pages WW-38, GW-69 and GW-72. I can see that the common link to the Horn and the Rear Window Defogger is the IPDM E/R (Intellegent Power Distribution Module Engine Room). Ground connections 14 and 45 at the CPU are common to both. Water is definitely your problem and the IPDM is where I would go.

Good Luck

 

yes fuse #35 (15A) is the one that I pulled, for now with this Canadian weather I would certainly take the rear defroster working over my horn. Taking from what you guys said i'm guessing theirs just water somewhere in the harness or I've unfortunately shorted out my ipdm-er, do you think its completely broken and I should just order up a new one?? (I suck with this electrics garbage), hopefully I can pull it all apart and see if drying it out solves the problem.

Thanks for the input.

 

Removing the IPDM ER and cleaning the contacts with electrical contact cleaner would be my first route, this is all you might need to do. I have never removed the IPDM and don't know if it even comes apart, but if it has a removable cover then I would remove it and clean it internally. It is possible that a good cleaning and drying off is all you need to do, don't forget to clean and dry off all the other electrical components in that area well. Obviously you figured it it out, all these components sit over the wheel well, do you have all your wheel well covers and under engine engine covers installed?

 

yes I have all my covers installed, ill have it into the garage to try and pull everything apart tomorrow and clean it, ill keep you updated, hopefully all goes well.
Thanks for the input
-clayton

 

I gotta revive this thread, I've got the exact same issue, didn't drive the car since Christmas, left it out in the cold, flat flat dead battery, boosted it, and now my defroster turns on the horn. I've taken all the fuses and relays out and wiped them down with IPA. No dice. Did some googling, apparently there's an improved ipdm for cold weather no start issues, 05+ coupes part number is 284B7-AQ01B. Has anyone fixed this before, or do I need to go to the junk yard and hunt for a newer ipdm?